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APRIL 19BO 



HEWLETT-PACKARD JOURNAL 



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Br. 1949-1998 Hewlett-Packard Co. 



HEWLETT-PACKARD JOURNAL 

Tflchmcal information from Ihe Laboratories of Hewlett-Packard Company 

APRIL 1980 Volume 31 • Number 4 



Contents: 

Microwave CW and Pulse Frequency Measurements to 40 GHz, by Richard F. Schneider, 
Ron aid E. Fetsenstein, and Robert W. Offermann As radar and communications systems 
reach for higher frequencies, test equipment becomes more sophisticated. 

A 400-to- 1600- MHz -^8 Prescaler, by Hans J. Jekat State-of-the-art technology went into 
its tiny ampiifier l attenuator, and binary circuits. 

An Automatic Microwave Frequency Counter Test System to 40 GHz, by Larry L 

Koepke Testing high-performance microwave counters isn't a trivial task ( but this system 
does it automatically. 

40-GHz Frequency Converter Heads, by Mohamed M. Sayed The heads down-convert 
microwave input signals to frequencies that are more easiiy transmitted over coaxial cables. 

A 26.5-GHz Automatic Frequency Counter with Enhanced Dynamic Range, by Alt 

Bologiu Heres a cost-effective counter with sensitivity in the microwatt range. 

Microwave Counter Applications, by Richard F, Schneider Radar, oscillator, and general 
high-frequency measurements are described. 

Laboratory Notebook — A Flexible Software Development Technique, Ronald E. 

Fetsenstein if you have read-only memory to spare, you can use it to make changes in 
long-lead-time masked ROMs that you've already ordered. 

In this Issue: 

40 GHz stands for 40 gigahertz, which is the scientific way to say 40,000,000,000 cycles 
per second. That s a high frequency, 500 times higher than VHF television broadcast 
i frequencies, but still 10.000 times lower than visible light. Equipment that operates in the 
4-to-40~GHz range includes police speed detection radars, military and commercial air- 
craft radars, line-of-sight communications systems, and satellite up and down links. Even 
higher frequencies are in use. too. There's equipment in current production that operates 
up to 60 GHz, developmental systems that go up to 1 10 GHz or so, and experimental de- 
vices in the 2-300 GHz range. Two atmospheric windows at 34 and 94 GHz are of particular 
interest — these are frequencies at which the earths atmosphere appears much more transparent than it does at 
other frequencies. 

This month s issue and cover photo are devoted to some new high-performance microwave counter products 
that help test this high-frequency equipment. The system described in the articles on pages 3 and 14 measures 
frequencies as high as 40 GHz. whether the microwave energy is continuous or in the form of short bursts or 
pulses, The counter described in the article on page 20 measures the frequencies of continuous microwave 
signals up to 26.5 GHz. 

Here's a question for designers of microprocessor-based equipment. What do you do when you find you have 
more read-only memory than you need to microprogram all the functions your equipment is supposed to have? 
Why, you add more functions, of course. Many a product has been upgraded in capability for very little added 
cost by using extra ROM space. But on page 25 you II find another suggestion for using that spare ROM, If you 
save it for corrections to the basic ROM, you'll be able to order masked chips much earlier for all of your ROM 
except the chip that contains the corrections. That one can be an erasable ROM until all of the microcode is final. 
It's a simple way to get into production faster, 

-R. P. Do! an 

Editor, Richard P Dolan * Contributing Editor. Howard L Roberts * Art Director, Photographer, Arvid A. DanieSson 
Illustrator, Nancy S. VanderWoom t Administrative Services, Typography. Anne S. LoPresti * European Production Manager, Dick Leeksma 

2 HEWLETT-PACKARD JOURNAL APRIL 1 980 © K • i Company 198C Pnnted in U 5 A 

©Copr. 1949-1998 Hewlett-Packard Co. 




Microwave CW and Pulse Frequency 
Measurements to 40 GHz 

A new harmonic heterodyne frequency converter plug -in 
adds automatic 40-GHz frequency measurements to the 
universal capabilities of HP's top counter. 

by Richard F. Schneider, Ronald E. Felsenstein, and 
Robert W. Offermann 



TO BE USEFUL in the widest possible range of appli- 
cations, a microwave counter should be capable of 
measuring the carrier frequencies of pulsed or CW 
signals, and for pulsed signals, should also provide for 
time interval or frequency measurement of the pulse modu- 
lation The design should be optimized with wide IF bund- 
widths for narrow pulses and wide KM deviations, and 
should have high sensitivity. Cost-effective frequency 
range selection and automatic operation are essential. 

A new system that operates as a plug-in to the HP 5345A 
500-MHz Universal Counter 1 is designed to meet these re- 
quirements over a carrier frequency range of 0.4 to 40 GHz. 
The system, which consists of the 5355A Automatic Fre- 
quency Converter and the 5356A/B/C Frequency Converter 
Heads, is shown in Fig. l. It provides an effective a Iter native 
to the complex specially assembled systems that formerly 
were the only way to measure up to 40 GHz, 

The S356A/B/C Frequency Converter Heads eliminate I he 



need for microwave transmission lines to connect the mea- 
sured source to the counter. Coaxial cables, while conve- 
nient, cannot always be used r since two- metre coaxial lines 
typically have about 10 dB loss at 18 GHz and get worse at 
higher frequencies. To circumvent this, hybrid microwave 
circuits in the heads down-convert incoming frequencies to 
intermediate frequencies (IF) that are easily transmitted 
over a 1, 7-metre miniature coaxial cable to the 5 3 55 A Au- 
tomatic Frequency Converter Plug-in. This eliminates the 
transmission line loss and effectively improves system sen- 
sitivity by that amount. Heads with various coaxial or 
waveguide connectors can be selected to meet the mea- 
surement requirement (see article* page 14). 

Microprocessor control in the plug-in makes operation 
automatic in either pulse or CW mode. The new system uses 
the single-sampler harmonic heterodyne technique. 2 The 
microprocessor computes the input frequency according to 
the desired resolution set nn the 5345A Counter front panel 







Fig. 1. Model 5355,4 Automatic 
Frequency Converter plug-m for 
Model 534 5 A Counter measures 
the frequencies of CW of j 
signals up to 40 GHz. Down- 
conversion of the tnput frequency 
takes place in the interchangeable 
5356AlB>C Frequency Cottvm&i 
Heads, eliminating the need for 
high - he quen cy tra nsmis s 1 1 
between the source s/l 
counter External gating makes it 
possible to measure the frequency 
profile wtthin a pulse. 



APRIL 19BOHEWLEF I I ftC* &RD JOURNAL 3 



)Copr. 1949-1998 Hewlett-Packard Co. 



5355A Automatic 
Frequency Converter 



Externa* Gate 



Input 



5356A.B C Head 



Sampler 
and Driver 



IF Amplifier 
Pulse AGC 
CW AAD' 



Filter 
Deieclor 



■ 


HI 


■i 


2- Modulus 
Frequency 
Synthesizer 


H 






Synthesizer 
Control 



*AAD- Aulomalic Amplitude Discrimination 

and displays the frequency on the counter's eleven-digit 
display. 

The 5355 A plug-in has a simplified keyboard that allows 
the user to select automatic or manual CW or pulse opera- 
tion, to specify frequency offsets or multiplication of the 
measured frequency by a constant, to display freqttein . 
deviation, and to select the prescaler built into the plug-in. 
The prescaler divides the input frequency by eight. It is 
used to measure frequencies from 0.4 to 1.6 GHz; no fre- 
quency converter head is needed in this range. The pre- 
scaler has its own fused front-panel connector. 

Pulse repetition frequency measurements and time inter- 
val measurements such as pulse width, pulse repetition 
interval, pulse repetition period, and puise-to-pulse spac- 
ing are made by the reciprocal-taking 5345A Counter, using 
the detected IF from the 5355A Converter plug-in. The 
counter mainframe also measures frequencies from 50 jxHz 
to 500 MHz. The counter has a maximum time interval 
resolution of two nanoseconds for single-shot intervals and 
two picoseconds for time interval average measurements. 

The complete microwave counter syslem consisting of 
the 5345A Counler with the 5355A Frequency Converter 
and the 5356A/B/C Heads measures any frequency from 50 
MHz to 40 GHz. Its sensitivity with the 5356A/B Heads is 
-20 dBm from 1.5 to 12.4 GHz and -15 dBm from 12,4 to 
26.5 GHz, With the 5356C Head . sensitivity is 5 d B better up 
to 26\5 GHz and decreases to - 10 dBm at 40 GHz. Prescaler 
sensitivity is -15 dBm from 400 MHz to 1,6 GHz. 

In the automatic mode, the system measures the frequen- 
cies of KF pulses from 100 ns to 20 ms wide a I pulse repeti- 
tion frequencies of 50 Hz to 2 MHz. In manual mode, pulses 
as narrow as 60 ns can be measured, and external gates as 
narrow as 20 ns may be applied to the counter for applica- 
tions such as measuring the frequency profile within a pulse. 

For pulsed RF-signals T the FM tolerance is 50 MHz peak- 
to-peak for a 100- ns pulse in the automatic mode, and BO 
MHz p-p for a 60-ns pulse in the manual mode. Automatic 
calibration of the 5345A mainframe assures accuracy to 3 
kHz in pulsed carrier frequency measurements. Resolution 
is selectable to as fine as 100 Hz by frequency averaging. For 
example, a 28,5-CHz pulse radar with a 1-fts wide pulse 
could be measured with a 10-ms gate time to a resolution of 
10,3 kHz and an accuracy of 43 kHz or about 2 parts in 10* 1 
(assuming no time-base error). 

For CW (continuous} signals, the maximum resolution is 
0.1 Hz up to 10 GHz and I Hz from 10 to 40 GHz. The FM 
tolerance is 1 5 MHz p-p in the normal mode and 60 MHz p-p 
in the special FM mode. 



Delay 
Line 






Fig, 2, Simplified block diagram 
of the harmonic heterodyne fre- 
quency conversion technique for 
CW and pulsed signals 

Harmonic Heterodyne System 

The harmonic heterodyne technique has been described 
in previous articles- Basically, a microwave sampler is 
driven at programmed synthesized frequencies, as shown 
In Fig. 2 r until a signal occurs in the passband of the IF 
amplifier, indicating that some harmonic of the sampling 
frequency is mixing with the incoming microwave signal to 
produce a countable IF. The microprocessor then executes 
an algorithm to identify the harmonic number N and the 
sign of the IF (sum or difference), and solves for the input 
frequency, according to the equation: 



L = NL ± IF 



(1) 



where f x is the input frequency, N is the harmonic number, 
and f s is the programmed synthesized frequency. 

The harmonic number is determined by changing the 
synthesized frequency slightly and measuring the change 
in the IF Frequency. 



\ 



I]F1 

ft - h 



m 



where fjy^ = IF when f s = fj 
f m = IF when f s = % 



The sign of the IF in equation 1 is determined by whether 
fjpj is larger or smaller than iu } . 

Pulse Mode 

The basic design parameters of the system were derived 
from the pulse requirements and the mainframe counter's 
capabilities, Linear programming* was used to optimize the 
system. Seven equations in five variables were salved sub- 
ject to various boundary conditions, including the 
minimum input frequency, the IF bandwidth, the IF guard 
band, the maximum harmonic number, and the minimum 
synthesizer frequency. The linear programming equations 
were entered into the computer and families of solutions 
were obtained for the five variables. Tradeoffs were then 
made to minimize the tuning range of the synthesizer oscil- 
lator and optimize the IF bandwidth. Finally, a separate 
computer program was derived to determine the minimum 
number of frequencies required to obtain complete fre- 
quency coverage. The result is a set of frequency tables, one 
for each frequency converter head, For example, with the 
18-GHz Model 5356A head, only 13 synthesizer frequencies 
are required. 



4 HEWLETT-PACKARD JOURNAL. APBfL 1980 



)Copr. 1949-1998 Hewlett-Packard Co. 



In the search routine the synthesizer is stepped instead of 
swept. The synthesizer frequency tables are stored in a 
ROM. and the synthesizer is stepped to the next frequency 
in the table after waiting the longest specified pulse repeti- 
tion interval of 20 ms. This is repeated until a signal appears 
in the IF passband of 157 to 330 MHz. Next the synthesizer 
frequency is digitally incremented 4 MHz and the IF 
passband is tested. If the incremented-synthesizer IF falls 
outside the passband, the search routine proceeds to the 
next frequency in the table. If the IFs for both synthesizer 
settings are within the passband, the calculation of N and 



the sign of the IF can proceed. 

After ihe initial acquisition in the IF passband of 157 to 
330 MHz, the IF can shift into the IF guard band without 
affecting the measurement. The guard band extends down 
to 78 MHz and up to 375 MHz. as shown in Fig. 3, If the 
IF moves out of the guard band, the 5355 A reacquires 
the input and discards the results of any measurement 
in progress. 

Automatic gain control of the IF amplifier in the pulse 
mode minimizes the required input signal onoff ratio and 
maintains the signal-to-noise ratio. An IF detector and a 



A 400-to-l 600-MHz -8 Prescaler 



by Hans J. Jekat 



Behind the 0,4-to-1.6-GHz input on the front panel of the 5355A 
Automatic Frequency Converter is a prescaler that divides the input 

frequency Dy eight to bring it within the range of the 5345 A Counter 
mainframe The prescaler operates m both the CW and pulsed RF 
modes. An arming circuit senses marginal signals to keep the 
counter from miscounting The prescaler input is protected by a fuse 
[hat is accessible from the front panel 

Ftg 1 is a block diagram of the prescaJer The latest state-of-the-art 
technology has been applied in the design of the attenuator, 
amplifier, and binary circuits. 



AGC Attenuator 

The attenuator and the AGC (automatic gain control) circuit (see 
Fpg 1) are used in both CW and pulsed RF modes AGC is very 
important m the pulsed RF mode, since unwanted signal during the 
off condition of the pulse sjgna* could cause the pulse detector to 
delay its gate closing Therefore the AGC is set to a level where the 
RF pulse can be counted, and the off portion of the pulse is then 



a m 




Fig. 2. Attenuate 

70-72 packages 



npltder, and binary (r ) are housed m 



Yellow 



Armed 



Input 400 MHje to T600 MHz 



►B Hi 



High Pass 
Filtejr 

400 MHz 



PIN 
Attenuator 




Bias 

Out + 8 






PRS Gate 



11.5V = On 



LV AGC 
J Donl Count 



Count 



Green 



Fig, 1 . Block diagram of the 400- 

1800 MHz ^-8 presenter tn the 
5355 A Automatic Frequency 
Converter 



APRIL 19BG HEWLETT-PACKARD JOURNAL 5 



)Copr. 1949-1998 Hewlett-Packard Co. 



Bias 




compressed to a point below the input sensitivity, thereby preventing 
noise counting and gate jitter. The attenuator contains four PIN 
diodes connected in a tt configuration There are two PIN diodes in 
'he transmission line compared to the one that is commonly used in a 
tt attenuator, The advantage is that ihe off capacitance is only half as 
great and therefore, The attenuation in The off condition is higher. The 
tradeoff is a slightly higher input VSWR. To get good high-frequency 
attenuation, the bypass capacitors are parallel-plaJed capacitors 
with an extremely low profile of 0.13 mm Parallel resonances and 
inductive reactances are not discernible, The attenuator is packaged 
in a TO- 12 four-lead package (see Fig, 2). 

2-to-1 600-MHz Amplifier 

The amplifier used m the prescaler is constructed on a sapphire 
substrate measuring 2 5 by 6.4 mm Only two transistors and one 
chip capacitor have to be mounted on the sapphire substrate The 
rest at the circuitry conststs of thin-film resistors and thin-film induc- 
tors The low parts count in the amplifier yields a very high reliability 
The amplifier has ±1 dB flatness and 24 dB gain, and is housed in a 
TO- 12 package (Fig. 2), which uses little space on the prescaler 
printed circuit board 

1.6-GHz Binary 

The 1.6-OH2 binary (>2 circuit) is a monolithic high-frequency 
divider circuit (see Fig. 3j. Two current-mode flip-flops are cross- 
coupied in a master-slave configuration. Second-level current 
switches control updating and latching of the flip-flops Two input 
bias lines to the master flip-flop second-level current switch control 
serf-oscillation and bandwidth by preb?as?ng the data transistors 
This makes Shehi switch taster, since they do not have to wait tor the 
Total output swing of the slave flip-flop. This technique requires a 
larger voltage swing for lower frequencies, and since the voltage 
swing is limited, the low-freQuency response is degraded In other 



Fig. 3. 1 6GHz binary (^2 cir- 
cuit) consists of two cross- 
coupled current-mode Nip- flops in 
a master-slave configuration, 

words, we are trading off low- frequency toggle speed for high- 
frequency toggle speed. 

By controlling the clock input bias, the binary can be pushed into 
self-oscillation around 1200 MHz. At this point, the binary is m its most 
sensitive region over the entire bandwidth, The binary stops oscillat- 
ing and begins dividing when an RF pulse appears at the prescaler 
input. In CW mode, the 1,6-GHz binary is biased to a point of no 
self-oscillation. This sacrifices some sensitivity but assures that the 
counter will not respond to noise. In pulsed RF mode, the binary can 
be biased in the more sensitive oscillating mode since the gate signal 
dictates which signal is counted. 

The binary is packaged rn a four-lead TO-12 package (see Fig. 2} 
and the casting of the prescaler acts as a heat sink for it. 



Californ 

soccer 



Hans J, Jekat 

Hans Jekat is an electrical engineering 
graduate of the Techmsche 
Hochschute in Munich. He moved to the 
U.S.A. in 1958. and since 1964 has 
been with HP's Santa Clara Division, He 
served as project leader for the 530O 
Measuring System and designed the 
5300A mainframe, the 5305aJb Count- 
ers, several of the MOS/LSI circuits 
used m the 5300 system and other in- 
struments, and the prescaler and IF 
amplifier for the 5355A Frequency Con- 
verter His counter work has resulted in 
several patents Hans is married, has 
two sons, and lives in Redwood City 

ia. For many years a trainer of show horses, he also enjoys 

and skiing 




6 HEWLETT-PACKARD JOURNAL APRIL 1380 



)Copr. 1949-1998 Hewlett-Packard Co. 



I 5^ 5 



78 






375 



\ 



/ 



f(MHz) 



" Guard Band ■ 



Fig. 3. 5355A IF passband extends from J 57. 5 to 330 MHz 
for the down-converted carrier frequency The guard band 
allows for worst-case FM on the earner of 45 MHz peak The 
specification is 80 MHz peak-to-peak for pulsed signals 

gate generator provide the 534 5 A Counter with an external 
gate signal about 3Q ns shorter than the pulse burst and 
centered on the burst to eliminate measurement of the rise 
and fall frequency transients. 

Calibration 

The main gate circuits in the 5345A Counter have an 
asymmetry that causes a small difference between the lime 
it takes for the gate to open and the time it takes for the gate 
to close. This difference, typically about 300 picoseconds, 
becomes significant when the gate is opened and closed 
many limes for a single measurement on narrow pulses. The 
error is proportional to the intermediate frequency and in- 
versely proportional to the input pulse width. 

To minimize the effect of this error, an automatic calibra- 
tion routine in ihe 5355 A is used whenever pulse bursts 
narrower than 100 jts are measured. The calibration routine 
uses the synthesizer signal for a reference frequently hy 
Switching ihi.s signal Into the IF after dividing by four. 
r iiiM the gate derived from the input signal, this reference 
signal is measured, and the ratio of the actual synthesizer 
frequency to that measured is computed and used as a 
calibration factor. To improve the accuracy of the calibra- 
tion factor, it is averaged lor I he first leu measurements after 
the signal is acquired, The letter C is displayed in the left- 
most position of the 534 5 A display during these ten mea- 
surements to indicate lhat calibration is taking plm > 

A change in the input pulse width of more than 12%, Of 
loss and reacquisition of the input, will cause a new calibra- 
tion cycle to take place & special operating mode disables 
the calibration scheme for relative frequent :\ measurements 
where absolute accuracy Is nol required. 

Pulse Algorithm 

The flow diagram shown m Pig. 4 outlines the search, 
acquis! I inn, calibration, computation, and measurement 
cycles of the pulse algorithm. The harmonic number de- 
termination is made with a MN)~/lls minimum gate time. A 
normal pulsed frequency measurement is made offip] and 
h M tor synthesizer fretjiaoncies U ai1 ^ fa« rosp^Gtivety 
The harmonic number N is then computed as follows 



fa.- 



N = — — x Calibration Fat toi 

4 MM* 



Pulse 



1 



Compute f,, N per t n 



^^r 


Prescai** 








ves 


Yes 


< 




► 






Search f., Table 
are witbrn IF- 






— *U — 


. 



First Ten 
Measurements 



Measu 



ration Factor = 



f t Actual 



I, Measured 




Measure ijQ 



f p =S(VB)'C*l FiCtOf 



Measure f„ I ■ Measure f IF ( 



Measure 1 t ej 



f s = N-f, ± fo-Cal Factor 



H = Cal Factor 



l g = N'f) ± f,Fi Cal Factor 



HP-IS Output 



Display Result 



Definition ot Symbols: See Fig, 6, page 9 

Fig. 4. Search, acquisition, calibration, computation, and 
measurement algorithm for pulse measurements. 



APRIL 1M0 HEWLETT-PACKARD JOURNAL 7 



)Copr. 1949-1998 Hewlett-Packard Co. 



Microprocessor 
Control 



ROM 

Frequency 

Table 




10 MHz From 
Counter Time Base 



Pseudorandom 
Sequence 
Generator 













i_TT~ 


o 1 


i 


Detector 

and 

Gale Generator 















A Channel 
B Channel 



External Gate 



Fig. 5. in CW mode, a pseudo- 
random sequence generator 
modulates the VCO frequency A 
and B counters measure the two 
VCO frequencies and the corres- 
ponding intermediate frequen- 
cies. This information makes tt 
possible to identify which har- 
monic of the VCO ts mixing with the 
input to produce the IF The length 
of the pseudorandom sequence 
determines the allowable FM in the 
CW mode 



N is continually measured during an automatic measure- 
ment. 

For a 100-ju.s gate time, the time required for a pulse 
frequency measurement is 2x100 /xs divided by the duty 
[actor of the pulse signal. Since lire duty factor is the gate 
width multiplied hy the pulse repetition frequency, a t-^ts 
wide pulse with a 1-kHz repetition rate requires 200 ms to 
measure. 

CW Mode 

] hirmnnic number determination in the CW mode uses a 
pseudorandom sequence technique described previously* 1 
to improve tolerance to l-M The counter's FM tolerance of 
15 MHz p-p is related to the length of the sequence, which is 
normally set for 22 ms, A special mode lengthens the se- 
quence to HBO ms lor fiU MHz p-p FM tolerance. 

The pseudorandom sequence is applied to the frequency 
synthesizer at the VCO (voltage-controlled oscillator | in- 
put, as shown in Fig. 5, at a rate outside the phase-locked- 
Joup bandwidth. The loop remains locked, but (he 
pseudorandom sequence modulates die VCO frequency 
about 4 MHz peaJt-to-peak. The harmonic number and the 
sign of the IF are determined by switching the counter 
between the A and B channel inputs synchronously with 
the 4 MHz modulation step. The pseudorandom sequence is 
activated twice, once to measure the synthesizer frequency 
change and once to measure the corresponding IF change. 
In each case the frequency change is the difference between 
the A and B counts. To determine M the IF change is divided 
by I he synthesizer change and the result is rounded to the 
nearest integer (see next section]. With this technique, only 
one synthesizer is needed (many systems switch between 
two synthesizers to determine \ T ). The CW frequency reso- 
lution, a measure of the synthesizer noise spectral density, 
1$ typically less than ±2 Hz at 18 GHz with a one-second 
gate time. 



Automatic amplitude diseriminalion is provided in the 
CW mode by using a limiting II amplifier and providing an 
IF bandwidth that is greater than half the sampling rate. 
This tends to make the average zero-crossing rate equal to 
the frequency of the highest-level signal present. The 
counter will measure this frequency, provided that this 
signal is more than i\ dB greater than signals williin 500 
MHz and 2d dH greater than other signals within [he fre- 
quency range of the 5356A and 535GB Heads 

CW Algorithm 

The CW algorithm is shown in Fig, 6. Note that the syn- 
thesizer deviation is measured as well as ihe IF deviation. 
Phis is required to determine the synthesizer deviation 
accurately, since the modulation sensitivity of the VCO is 
not perfectly linear. The harmonic number N is then com- 
puted as follows: 



N 



#2 



The harmonic number is checked every ten gale tiuies to 
make sure it is correct. 

Synthesizer 

The divide-by-M frequency synthesizer is phase- locked 
to the 10-MHz time base of the 5345A mainframe. It oper- 
ates from 885.2 to 1056 MHz. A two-modulus divider, con- 
trolled by the microprocessor according to the frequency 
table stored in the ROM, sets the frequency as shown in Fig. 
7. Each converter head is coded so that when it is plugged 
into the 5355A N the proper frequency table is accessed. The 
VCO steps through the frequencies in a nonlinear manner. 
The minimum change is 400 kHz. 

The VCO output is amplified and sent to the 5356A/B/C 



8 HEWLETT -PACKARD JOUHMAL APRIL 1980 



)Copr. 1949-1998 Hewlett-Packard Co. 




Compule f v . N per f 



Yes 






Set r, 



1 



Measure i 
and Al,f during 
Pseudorandom Sequence 




Measure !# 



r, = n - 



HP-IB Output 



, Display Result 



CW Auto 



Fig. 6. CW measurement algorithm 



Definition of Symbols for Figs. 4 and 6 
Unknown prescaler frequency Input 
Synthesizer frequency 
Unknown RF heed frequency Input 
Dow reconverted tF (inler mediate frequency) 
Harmonic of f, that, mixed with f .,> produces f kF 
Keyboard- entered! manual frequency 
F c IF center passbend 157.5 to 330 MHz 
Value (or f« from a synthesizer table 
f i + 2 MHz 
U + 4 MHz 

Down-converted IF when f m = fi 
Down-converted IF when f , = h 




Head and to the phase-locked loop buffer amplifier. This 
signal is then divided by four and applied to the micro- 
processor-controlled -^M two-modulus divider. The two- 
modulus divider permits the setting of frequencies other 
than the normal integer values by switching between +40 
and -=-4 1 division factors. The phase detector has a reference 
frequency input of 100 kHz derived from the 10-MHz 
counter time base. 

In the CW mode, the harmonic number is determined by 
applying the pseudorandom sequence to the VCO input. 
The pseudorandom rate is outside the loop bandwidth so 
that the center frequency of the synthesizer is not perturbed, 
A high-and-iow-gain amplifier is used to optimize the sys- 
tem performance for both frequency measurement and M 
determination. Low gain is used during harmonic number 
determination so the maximum peak-to- peak deviation is 
obtained, while high gain is used during the frequency 
measurement to obtain the best spectral purity. 

Elliptical filtering is used to minimize the 100-kHz 
sidebands that are caused by noise on the 100-kHz reference 
signal feeding through and modulating the VCO. Another 
operational amplifier is used to condition a tuning signal 
that goes to a filter in the IF amplifier, This filter tracks the 
synthesizer tuning and maintains the IF amplifier cutoff 
frequency at about one-half the sampling frequency [syn- 
thesizer frequency) to minimize spurious responses. 

Special precautions were taken to reduce the power-line 
sidebands in the synthesizer spectrum. It was necessary to 
wrap the elliptical filter inductor with a mu-metal shield 
and place a sheet of transformer steel alongside the printed 
circuit board casting to obtain the specified resolution. 

IF Filter/Detector/Gate Generator 

The various IF bands are determined by three analog 
filters followed by level detectors as shown in Fig, 8. The 
edges of the acquisition band have Individual filters and 
detectors* while the guard band is determined by cascaded 
high-pass and low-pass filters followed by a single detector, 
All filters axe five-pole Chebyshev type and all detectors 
consist of a low-barrier Schottky diode and a capacitor. 

The IF input is limited and has constant amplitude. The 
detected level on each capacitor is compared to a reference 
voltage by a high-speed voltage comparator, the output of 
which gives a digital indication of the presence of a signal 
in the passband of the associated filter. By designing the 
filter so that the band edge frequency is several dB into the 
filter's stopband, the exact cutoff frequency can be set by a 
simple adjustment of the reference voltage, This allows 
precise determination of the band edges without precision 
trimming of the filters themselves, The outputs of the three 
comparators are combined by logic that produces four data 
lines from which the microprocessor can determine when a 
CW or pulse signal is present in the acquisition or guard 
bands. 

The detection scheme is fast enough to detect the pres- 
ence of a valid IF signal from a single 60-ns wide burst. This 
not only minimizes acquisition time in the pulse mode, but 
also allows these same circuits to be used for generation of a 
signal to gate the 5345A for pulse measurements. When a 
pulsed-RF signal is present in the passband of one of ihe 
filters, the output of the associated comparator approxi- 



APRIL t9fl0 HEWLETT- PACKARD JOURNAL 9 



)Copr. 1949-1998 Hewlett-Packard Co. 



High Low 
Gain Control 




100 kHz 



Reference 
Frequency 




Phase/ 

Frequency 
Detector 



Elliptical 
Filtering 



To IF 
Tuning 



Pseudorandom 
Sequence Modulation 



->E » B1 



Microprocessor 
Control 



To 5356 A B C 
RF Head 



Buffer 
Amplifier 



Fig, 7. The 5355 As frequency 
synthesizer generates the local 
oscillator signal to down-convert 
the input signal in the 5356A;B-'C 
Frequency Converter Head. 



mates the modulation envelope of the input RF signal. By 
using the comparator following the 78-to-375-MHz 
bandpass filter t a gate will be obtained whenever there is a 
countable signal present. However, it is not desirable to use 
this detected envelope directly as a gate. This is because 
pulse modulators commonly introduce a significant 
amount of phase distortion in the process of turning the RF 
signal on and off. Also, if the gate signal is the same width as 
the burst to be counted, the timing of the gate relative to the 
burst becomes extremely critical* For these reasons it is 
desirable to make the gate signal narrower than the burst to 
be counted, thus avoiding miscounts due to both I urn- on 
and turn-off distortion and to incorrect alignment between 
the gate and the RF burst* This is done by using a com- 
parator in the detector that has two outputs, each with an 
independent enable. One output is delayed and then used 
to enahle the other output, thus causing the leading edge of 
the second output to be delayed, However, when the RF 
burst ends, both outputs return to the no-signal state simul- 
taneously* The result is a pulse on the second output that is 
narrower than the input pulse by the amount of the delay, 
which in this case is 30 ns. This output is translated to I lie 



proper levels and routed to the ,H gate out" connector on the 
5355A*s rear panel. From there, it is connected to the gate 
control input on the 5345 A using the cable supplied with 
each 53 55 A. The IF signal is internally routed to the 5345A 
via a delay line of the proper length so that the gate pulse is 
centered in the IF burst at the 5345 A's main gate flip-flop, 
This timing relationship is shown in Fig. 9. 

Front Panel 

The 5355A has two inputs, one with a range of 400 to 
1600 MHz. and the other for the removable high-frequency 
RF head. A simple seven-pushbutton keyboard handles all 
the measurement and diagnostic functions, Must of the user 
applications are handled by three of the keys. The two 
right-hand keys determine a PULSE or GW measurement, 
and the bottom key selects the appropriate input. 

The four remaining keys are used for more sophisticated 
measurements, such as manual or offset measurements. 
These measurements require keyboard-entered frequen- 
cies. To enter a manual frequency, the gold MAN FREQ key is 
pushed to place the 53BSA in gold data entry mode. In this 
mode, the gold legends on the front panel apply. By using 



HPR/IF {Input Select) 



FOut 




LFDP0 (Reset) 



LFDRS (Read Enable) 



Fig. 8. IF frlter, detector, and gate 
generation circuits 



10 HEWLETT-PACKARD JOORNAL APRIL 1980 



)Copr. 1949-1998 Hewlett-Packard Co. 



RF Burst 



Comparator Output 



prove the resolution to 10 kHz. By frequency averaging, 
resolution maybe increased to 100 Hz. depending upon the 
total measurement time, as shown in Fig. 10* 

Gating errors in the 534 5A. described previously in the 
calibration section, cause frequency errors inversely pro- 



Enable input 
Gate Output 

Delayed RF Burst 




Fig. 9. 5-355A gate timing The gate sigrmt is shorter than the 

detected RF pulse and centered on ft. This eliminates mis- 
counts due to turn-on and turn-off distortion 

the two keys labeled UP and DOWN, the desired manual 
frequency can be entered. For a manual measurement the 
frequency entered must be within 50 MHz of the input 
frequency Pushing the gold key again restores the 5355A to 
its previous measurement mode. 

To enter an offset frequency, the blue OFFSET FREQ key is 
pushed to place the 5355A in blue data entry mode. In this 
mode, the blue legends apply. Using these keys, the sign, 
mantissa, decimal point, and units of the offset frequency 
can be entered. Pushing the blue key again restores the 
5355 A to its previous measurement mode. 

Diagnostics and special functions are engaged by push- 
ing two keys simultaneously. Pushing CW and PULSE acti- 
vates one of two specialized measurement modes, When the 
5355A is in CW mode, a long pseudorandom sequence is 
activated so that more FM can be tolerated at the input. 
When the 5355A is in pulse mode, the calibration factor is 
computed continuously [normally it is computed iin only 
the first ten measurements). 

Pushing the blue and gold keys simultaneously engages 
\ ,n iuus diagnostics and specialized modes. Each time these 
two keys are pushed, two digits centered between equals 
signs are displayed in the 5 34 5 A mainframe for one second. 
The digits identify which mode is being activated. A total ol 
21 modes are available. Presently. 17 have been assigned. 

All of the front-panel functions are remotely programma- 
ble via the HP- IB . * The programming resembles pushbut- 
ton operation for all measurements, diagnostics, and 
specialized modes, For data entry of manual and offset 
frequencies, a floating-point input format is used. 

Resolution and Accuracy 

The resolution of a frequency measurement is directly 
proportional to the gate time, For example, a l-/ts gate time 
provides a resolution of 1 MHz> To improve the resolution 
on CW or repetitive pulsed RF signals, frequenc_vayKraging 
is used. Averaging improves the resolution by \ n. where n 
is the number ol samples averaged. s For a 1-fts external gate 
signal and a 5 34 5 A ^ate time setting of lUms, 1(J 4 external 
gates are required to complete one measurement and im- 

^Compatible with 1£S 



An Automatic Microwave Frequency 
Counter Test System to 40 GHz 

by Larry L. Koepke 

Testing the 5343A Microwave Frequency Counter, the 5355A Au- 
tomatic Frequency Converter, and Ihe 5356A^B/C Frequency Con- 
verter Heads for con form rty to all of their specifications over the it 

entire frequency ranges is not a trivial task. To handle thus formidable 

job, a special automatic lest system had to be devised Some of its 

features are 

1 The software programs are structured to allow the operator to run 
a full set of tests automatic ally (without operator assistance), to 
select a single test to run, or to select frequencies and power 
levels manually (see Fig 1 1 

Special Function Keys 



«L 



Set and 

Read Status 

of 5355A 




Test 1 






Pro scaler 
CW Sensilitivy 
ami Accuracy 






Pre scaler 

Pulse 
Sensitivity 



Presealer 

Pulse 
Accuracy 



Te Sl 2 

Test 3 
Test A 



RF Head 
CW Sensitivity 
and Accuracy 



RF Head 

Pulse 
Sensitivity 






RF Head 

Putse 
Accuracy 



Test 5 



Test 6 



Test 7 



J^ 




Fig, 1. Test program structure and special function key as- 
signments in the Microwave Counter Test Sysft 



APRIL 1 960 HEWLETT-PACKAflO JOUFif I 1 1 



)Copr. 1949-1998 Hewlett-Packard Co. 



2. The system can make numerous repetitive frequency measure- 
ments at different power levels automatically, freeing the test 
technician to align and/or repair instruments thai have failed the 
automatic tests 

3 The system provides failure reports to help the test technician 
locate instrument failures. 

4, In the data log mode the system provides a printout of the com- 
piete test, 

5. The operator is made aware of a failure or the end of a test by an 
audible signal 

The Microwave Counter Test System is controlled by an HP 9825A 
Desktop Computer using HP-IB" signal sources {HP 3330B, 
HP8660C. HP 8672A) to derive the frequencies of 10 Hz to 40 GHz. 
Frequencies of 18.5 GHz to 26 5 GHz are derived by doubling the 
S672A frequencies of 9.25 GHz to 13 25 GHz Frequencies of 26 5 
GHz to 40 GHz are derived by quadrupling the 8672A frequencies of 
6.625 GHz to 10 GHz. 

The system is capable of supplying CW or puJsed RF to the instru- 
ments under test. A 5359A Time Synthesizer is used to generate 
pulses to modulate the CW signal generator outputs HP 3331 1 B/C 
Coaxial Switches used for signal switching and an HP 8495K 10-dB 
Step Attenuator are controlled via the HP-IB by ih/ee HP 59306A 
Helay Actuators. Two HP 436A Power Meters controlled via the HP-IB 
and one HP 432C Power Meter controlled via an HP 98032 A 1 6- bit I/O 
Interface mane the required power measurements. Frequency mea- 
surements on the combined 5355A Converter (listen only) and 
5356A/B/C Heads are made by the 5345A Counter and output via the 
HP- 1 B to the 9825A Desktop Compute r . 5343 A M ic rowa ve F req uency 
Counter frequency mea.su rements are out put directly via the HP- 1 B to 
the 9825 A A separate HP 98034 A HP- IB I/O interface was used for 

'Compaiible with IEEE 4B8-T978. 



the instruments under test (5343A or 5355A), so that an HP-IB failure 
in one of these instruments would not affect the system instruments 
under HP-IB control, which are on another 98034A HP-iB I/O Inter- 
face Fig. 2 is the system block diagram 

The instrument test programs, associated data files, and special 
function keys are stored on the HP 9885M Flexrble Disc When the 
system is first powered up the 9825A Computer automatically loads 
track 0, file 0; the Start program loads the special function keys from 
the flexible disc and displays press s.f rev for deSiRED unit The 
operator presses she special function key on the 9825A correspond- 
ing to the instrument being tested, and the instrument test program 
selected by the operator is loaded from the 9885M Flexible Disc »nto 
the 9825A memory and executed from line The operator now 
answers queslions asked by the 9825A do you wish to data log 9 yes 
or no; if yes enter the date, enter the instrument serial number The 
complete test is then executed 



Larry L Koepke 

Larry Koepke nas been a test and elec- 
tronic tooling technician with HP since 
1959, Born in Rockford, Iowa he 
learned his electronics in the U.S. Army. 
| He assembled the test system and 
" wrote the test programs for the 5355A 
6 Frequency Converter, the 5356A/B/C 
Heads, and the 5343 A Microwave 
Counter A resident of San Jose. 
California. Larry is married, has two 
daughters and one grandson, and likes 
id r ide horses and bicycles. 




Frequency 

Synthesizer 

2-18 GHz 







Pulse 
Modulator 




Pulse 
Generator 



w 



To Ext 
Counter Gate w 



Pulse 
Modulator 



Frequency 

Synthesizer 

12 MHz - 2 GHz 



Frequency 

Synlhesteer 

1G Hz- 12 MHz 



m m* 



Desktop 
Computer 



A'::.- 





Thermistor 

and Power 

Meter 



A 



Fig. 2. Block diagram of the Microwave Counter Test System, 



Unit Under 
Test 



A 



12 HEWLETT-PACKARD JOURNAL APRIL 19BD 



)Copr. 1949-1998 Hewlett-Packard Co. 



10 MHz -r 



1 MHz-r 



100 kHz — 



LU 

u 10 kHz — 



1 kHz -- 



100 Hz 



Gate Error 



10 Hz 




+ 



- 



- 



20 ns 100 ns 



1 fts 10 ^s 100 fi$ 
External Gate Width 



1 ms 



10 ms 



Fi g . 1 . Gate error an d res olution of frequ en cy a vera ge mea - 

surements as a function of gate width 

portions! to external gate width. The calibration routine 
improves the accuracy about one order of magnitude. The 
residual gate error, shown in Fig. 10, is independent of gate 
time and may be decreased to 3 kHz for external gate widths 
from about 4/^s to 100/is. Since the resolution of the calibra- 
tion factor is not zero and secondary 5345A main gate errors 
are present A kHz is the accuracy limit. However, calibra- 
tion is not used for external gate widths greater than IQOps, 
so the accuracy is the same as the 5M5A Counter in this 
region. 

Since no pulse burst standard exists, pulse accuracy mea- 
surements are made with a CVV source with the mainframe 
counter externally gated. Actual pulse measurements usint^ 
the test equipment described on page 1 1 typically are more 
accurate than the specification, Fig, It shows the results of 
typical pulse measurements on an lfl-CiHz synthesizer as a 
function of pulse width. 

Pulse modulation of a source causes phase modulation of 
the carrier, especially during the rise and fall times of the 
pulse. This can be a result of direct I 1 M or *t J M, AM-tn-FM 
conversion , or frequency pulling of the source. A video 
signal (feed through of the pulse modulation) may also be 
present along with the modulated carrier, further distorting 
l hi* waveshape. Although the 5355A T s adaptive gate 
generator removes about 1 5 ns from the leading and trailing 
edges of the pulse, some phase modulation may remain, 
especially for short pulses. Therefore, frequency accuracy 
for burst measurements depends on input signal purity; any 
phase perturbations that cannot he removed by the 5355 A 
will cause errors. 

A typical GVV statistical measurement of a synthesized 
18-GHz source with the source and counter time bases tied 
together using a 1-8 gate time had a standard deviation (one 
sigma) of 0.57 Hz and a mean difference of -Q.0H Hz for 
1000 measurements. 



Self Check 

The 5355 A can perform six measurements, two using the 
prescaler input and four using tiie RF head input. With the 
prescaler, either pulse or CVV mode can be selected. With 
the RF head, pulse auto, CVV auto, pulse manual, or CVV 
manual can be selected. 

The 6800 microprocessor executes these complex al- 
gorithms using I2K bytes of ROM and IK bytes of RAM. 
With the flexibility the microprocessor allows, it was easy 
to implement special self-check routines that execute 
whenever the instrument is turned on. In the 5355A, the 
two RAM integrated circuits are verified for data-pattern 
read 'write and addressability, Then the tw r o ROM inte- 
grated circuits are tested via a checksum- Following RAM 
and ROM tests, the synthesizer is programmed to three 
known frequencies and performs three lOihfis measur- 
ments to verify each setting. Should any of these power-on 
tests fail, the operator gets a unique ten-second warning 
display per failure. Thereafter, the 5 3 55 A will attempt to 
follow the measurement algorithm specified by the user, 

Ac k n o w I e d g m ents 

The team that developed the 5355 A and the 5356A/B/C 
was as follows: Luiz Peregrino did most of the initial inves- 
tigation, systems analysis, and synthesizer design. The 
MPU/HP-IB hardware was developed by John Shing. 
Mnhamed Saved was responsible for the 53 5b A H ( ! heads 
He developed the 40-GHz sampler, VCO, sampler driver, 
high- pass filter, and power amplifier hybrids, and provided 
the integration and testing of the heads. The prescaler 
channel was the responsibility of Hans Jekat t who also 
designed the IF amplifiers and provided many solutions to 
systems problems. The mechanical designer of the 5355A 
was Hick Goo, and of the 5356A/B/C was Keith Leslie- Tool 
design was by Jerry Curran. Martin Neil provided the initial 



10 MHz -r 



1 MHz — 



tOO kHz — 



£ 10 kHz- 



1 kHz- 



100 Hz f 



10 Hz 






Specified Accuracy 



Typical Measurements 



*- 10 fis PRP-p--» 0.10 Duty Factor - 
^ — 10 ms Gate Time — *-*-1D0 ms- 



Gaie Time 



*-— 1 s** 

Gate Time 

■ 



• 



20 ns 100 ns 1 pes 10 j/S 100 f is 1 ms 10 ms 

External Gate Widlh 

Fig. 1 1 . Typical measurements on an 1 8-GHz pulsed source 
Peak pulse power is - 10 dBm. Each potnt is the average of 
100 measurements. 



' m HEWLETT -PACKARD JOURNAL 13 



)Copr. 1949-1998 Hewlett-Packard Co. 



marketing introduction, and Larry Johnson completed that 
assignment. Randy Goodlier was the service engineer, and 
Larry Koepke built the microwave counter test system and 
wrote the software, Quality assurance was under the sur- 
veillance of Joe Bourdet. Alex Campista and Ron Hartter 
were the pilot run technicians, fan Band was the lab en- 
gineering manager and Roger Smith the microwave counter 
section head. Many thanks to all of the people above and to 
all of the others that contributed to the production of these 
instruments. 

References 

1. J.L. Sorden, "A New Generation in Frequency and Time Mea- 
surement," Hewlett-Packard Journal, June 1974, 

2. A. Bologlu and V,A> Barber, "Microprocessor- Control led Har- 
monic Heterodyne Microwave Counter also Measures 
Amplitudes,"" Hewlett-Packard Journal, May 197B. 

3. S.L Gass, "Linear Programming, Methods and Ap plications, " T 
McGraw-Hill, 1964. 

4. L. Peregrino. "A Technique that Is Insensitive to FM for Deter- 
mining Harmonic Number and Sideband,'' Hewlett-Packard Jour- 
nal. May 197B, 

5. D.C, Chu T "Time Interval Averaging; Theory ( Problems, and 
Solutions," Hewlett-Packard Journal, June 1974, 



Richard F. Schneider 

Dick Schneider is project manager for 
the 5355A Frequency Converter and 
the 5356A/B Frequency Converter 
Heads. With HP since 1964, he's con- 
tributed to i he design of the 5240 A, 
5260 A, and 525 7 A counter products, 
| developed several microwave counter 
and phase-lock systems, and served as 
p rojec! manager for the 5340A Co unter. 
A native of Cleveland. Ohio, he 
graduated from Case Institute of 
Technology with a BSEE degree in 1952 
and spent several years designing rrus- 
sile and satellite test equipment, mi- 
crowave amplifiers, and telemetering, 
radar, and receiving systems before joining HP He also served in the 
U.S Coast Guard as a Loran specialist. Dick is a member of IEEE and 
holds an MSEE degree from California State University at San Jose, 
received in 1968. He's married, has two sons r and relaxes with tennis 
and woodworking. 







Robert W. Offermann 

Bob Offermann received his SS degree 
m electrical engineering from California 
Institute of Technology \r\ 1 971 , and for 
the next two years combined circuit de- 
sign work at the U S Naval Undersea 
R&D Center with graduate studies at 
Caltech He received his MS degree rn 
1973 and joined HP shortly thereafter. 
Bob has contributed to the design of the 
5363A Time Interval Probes, done in- 
vestigations on time interval measure- 
ments, designed the IF and gating 
circuits for the 5355A Frequency Con- 
verter, and served as the first 5355A 
production engineer. A native of Stock- 
ton, California, he now lives in Saratoga, California. He's married and 
enjoys swimming, sailing, ballroom dancing; and theater 




Ronald E. Felsenstein 

| With HP since 1969, Ron Felsenstein 
| designed the processor for the 5345A 
I Counter, served for a year as a laser 
and logic production engineer, and was 

responsible for the 6800 firmware and 
the digital interface design for the 
5355A Frequency Converter. Born m 
Montevideo, Uruguay, he received his 
SB degree in electrical engineering 
from Massachusetts Institute of 
r Technology in 1 969. Now a resident of 
Santa Clara, California, Ron and his . 
family (he's married and has two chil- 
dren) enjoy winter camping in their re- 
cently acquired motorhome. Ron col- 
lects U.S. stamps and coins and is a dedicated do-it-yourselfer when 
it comes to car and home repairs. 




jtr 



40-GHz Frequency Converter Heads 

by Mohamed M. Sayed 



THERE IS AN UPPER LIMIT to the frequencies at 
which automatic microwave frequency measure- 
ments may be made simply by connecting a coaxial 
cable between the source and the counter. This is because 



the cable's losses are generally greater for higher frequen- 
cies, thus demanding more sensitivity from the counter, 
while microwave counters become less and less sensitive at 
higher frequencies. Thus a frequency is reached where not 



14 HEWLETT-PACKARD JOURNAL APRIL 19 



)Copr. 1949-1998 Hewlett-Packard Co. 





Fig. I. Model 5356 A, B'C Fre- 
quency Converter Heads offer a 
choice of input connectors and fre- 
quency ranges tor microwave fre- 
quency counting up to 40 GHz 



enough signal reaches the counter la trigger it properly, 
These conditions dictate using a waveguide instead of a 
coaxial cable, However, waveguides are suitable only tor 
certain frequency bands, e.g.. K-band [1&-2&5 GHz) or 
R-band (26,5-40 GHz), Moreover, they are expensive and 
lack the mechanical flexibility of the coaxial cable, 

'■wt:\ Converter Heads Models 5356A/B/C, l v ig. 1. 
combine the convenience of coaxial cables with the broad 
frequency band oi a microwave counter I I 1-40 GHat), and 
can be us I u oj pulse measurements, These 

heads convert microwave frequencies to intermediate fre- 
quencies (IK) using the sampling tet hniqtte Fha sampling 
frequency input to the head and the IF output from t1 are 
connected by a 1.68-metre cable to the 53-S5A Automatic 
Fraquenc) Gbnvertiar (see article page 3), The microwave 
ifi I nit frequency to the head is calculated from measure- 
ments of the I!- and the answer is displayed on tin- 53 4 5 A 
atfif | the 5355A js a plug-in lor the 5345A)« The down- 



Table 1 

Frequency Ranges and Connectors of 
Model 53S6A/B/C Frequency Converter Heads 



FREQUENCY 


HEAD 


CONNECTOR 


HEAD CODE 


1/5-18 GHz 


5356A 


N 


'i 


1.5-26,5 GHz 


53S6B 


SMA 


1 


lfl-26.5 GHz 


S.WiB Dpi 001 


Waveguide 
[WK-42] 


l 


1.5 40GKz 


5.J5&G 


APC-3^ 


\ 


>GHz 


5356C Opt, 001 


Waveguide 

lWK-28) 


S 



conversion is performed completely in the head and nnh 
the [F is connected to I tie 5355 A. 

To cover the frequently baud Up tb 4(1 ( \\ \z. four different 
connectors are available: N, SMA, r\FC-3.5and waveguide. 
Three models and two options are available to su|1 various 
applications, Table 1 shows the frequency ranges of the five 
heads. 

rhe heads have male connectors because sources gener- 
ally have female connectors. The 5356A h;m an N-type 
connector and is useful up to 15 GHz, The 5356B has an 
SMA connector and Gan be used tip to 26,5 GHz. To 
strengthen the SMA rnale i onne< tor, a spei ial collar was 
designed i r n prut eel it. The collar also makes it easier for the 
merto connect it to the source. Some customers prefer 
using a K-band waveguide from 18 to 26 5 I r] I/.: the 5356B 
Option 001 has s Wfr42 connector to meet this need. The 



Input f, 
1.5-40 GHz - 




Coaxial 
Assembly 



IF 
Amplifier 



IF Output 



V528 MHz 

to 5355A Automatic 

Frequency Converter 



Sampler 
Driver 



Power 
Amplifier 



-^ VCO Input 



BBS. 2-1056 MHz 
from 5355 A 

Fig. 2. Simplified block diagram of the 5356AtB?C Frequency 
Convener Heads. 



APRIL 1BB.0 HEWLETT-PACKARD JOURNAL 15 



)Copr. 1949-1998 Hewlett-Packard Co. 



40-GHz Synthesizer Tests Frequency 
Converter Heads 

by Mohamed M. Sayed 



APC-3.5 connector, which is mode-free to 34 GHz, 1 is used 
up to 40 GHz in the 535fiC. The effect of this connectors 
moding between 34 and 40 GHz is taken into account by 
reducing the specified sensitivity by 5 dH in this region, A 
special collar whs designed for the A PC- 3, 5 connector to 
strengthen it and to protect it from damage. Waveguide 
nonnector WR-^I is alsu ultttrnd. for customers using only 
R-band (20,5 tn 40 GHz). 



To test the accuracy of the 5356/5355 system in CW and pulse 
modes, a synthesized source is needed, especially so check for 
*1 -count accuracy with a one-second gate time. Both synthesizers 
and puise modulators are commencany available up to 1 8 GHz, and 
these are used in the 5356/5355 test system To cover the 18-to- 
26 5-GHz band, an amplifier and a K-band doublet are used, The 
input frequencies to the doubler are 9 to 13 25 GHz and the output 
frequencies are 18 to 26 5 GHz as shown in Fig 1 

To 5356B/C 
18-26,5 GHz 




Synthesizer 
2-18 GHz 



Q«>fl § *fc 



9-13,25 GHz 



Pulse 
Modulator 



Time 
Synthesizer 



Frequency Converter Head Design 

Fig. 2 shows the block diagram of the S356A/B/C, The 
input voltage-con trolled oscillator (VCOj frequency la the 
535BA/B/C varies from 885,2 MHz to 1056 MHz and the 
output IF to the 5355A varies from 1 MHz to 528 MHz. The 
11' output is proportional to the RF input within the 
535EjA.'B'Cs dynamic range. All of the components in the 
head are built in thin-film mk:rocircuit configurations. 

The coaxial assembly shown in Fig. 2 is replaced by a 
high-pass filter for the 5356A Option 001. Since \lu- 5356/ 
5355 is a pulse counter, the input pulse may contain a video 
signal, This signal may be so large that it overloads the 
counter, especially since the IF gain is about 80 dB< To 
attenuate stieh video signals, Viodet 535GA option 001 has a 
high-pass filter between the input connector and the sam- 
pler. The filter's maximum insertion loss from 1.5 to 18 GHz 



Fig, 1. Generation of an 18-to-26.5-GHz Signal to test the 
5356B;C Heads. 

In the 26,5-to-40-GHz range an R-band doubler can be used, with 
the primary synthesizer operating from 13.25 to 20 GHz. This means 
that the synthesizer, the pulse modulator, and the amplifier must also 
operate up to 20 GHz. Since most of the instruments operate only up 
to 18 GHz, major modifications would have been needed 

The Simpler method that is actually used to generate a synthesized 
signal to 40 GHz is to use an amplifier and two doublers in cascade. 
The first stage is an amplifier-doubler, and the second stage <s 
another doubler. The primary synthesizer, the puise modulator, and 
the amplifier operate in the frequency range 6.625 to 10 GHz. Fig 2 
shows a block diagram of the 26.5-to-40-GHz synthesizer 






To 5356C 
26,5-40 GHz 




Synthesizer 
6-625-10 GHz 




Amplifier 



Amplifier 
Doubter 



Pulse 
Modulator 



6.625-10 GHz 13,25-20 GHz 



Time 
Synthesizer 



Fig. 2. Generation of a 26.>to-40-GHz signai to test the 
5356C. 



Acknowledgments 

Special thanks are due Roger Stancliff of the HP Santa Rosa 
Divisran for his help in designing the amplifier doubler 




a 






Input 
SS52 to 

1056 MHz 



Step 

Recovery 

pi ode 



Output 
1 to 40 GHz 



Fig. 3. Photo and schematic of the 5356 AS -'C sampler driver 
L j is dnve inductance and C : is tuning capacitance i 
L3, stnd C- f form a matching network to match the impedance 
seen at C t to 50tl 



16 HEWLETT-PACKARD JOURNAL APRIL T3&0 



)Copr. 1949-1998 Hewlett-Packard Co. 






I 



-to — 

-15 
-20 
-25 — 
-30 
-35 4 



12 4 6 B 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 

Frequency (GHz} 



Fig, 4. Spectrum of the sampler 

driver output shows comb Imes to 
40 GHz The input frequency is 
1 GHz 



is 1 dB, and its minimum insertion loss below 100 MHz is 
more than 35 dB. 

The power amplifier is housed in a TQ-8 package using a 
thin-film alumina substrate. It consists oi two Stages, a gain 
stage and a power stage. The amplifier is driven to satura- 
tion so that its output is insensitive to input variations. The 
IF amplifier is housed in a TO-12 package using a thin-film 
sapphire substrate. It also consists of two stages. 

The head casting consists of an upper half and a lower 
half. The sampler and the two printed circuit boards are 
mounted on the lower half. Heat sink materials are attached 
to the upper half to dissipate ths heat from the power 
amplifier and the IF amplifier. There is also a heat sink on 
the lower half for I lie power amplifier. As a result, the 
temperature rise is less than 9 C. The heat sink materials 
also serve as shock absorbers for mechanical vibrations. The 
casting is designed toaccepl the different input connectorsi 
N. SMA, APC-3.5. waveguide IYR-42. and waveguide 
WR~2& The casting is also designed for improved KMI 
[electromagnetic interference} performance. All of the parts 
inside the head can be disassembled easily, using a screw- 
driver and an SMA wrench* As a result, I he 5356A/ffiC is 
easy to troubles hoot. 



Sampler Driver 

The heart of the frequency converter head is the sampler 
driver. Fig. 3 show r s a schematic diagram. The driver is built 
in a coaxial package. The step-recovery diode has a very fast 
rise time that generates a comb of harmonics of the VCO 
frequency. One of the comb frequencies is heterodyned 
with the input microwave frequency to produce an IF out- 
put in the proper range. 

When time domain measurements were used to test the 
sampler driver, the test parameters were very sensitive to 
operator error and test equipment limitations, Therefore, 
frequency domain measurements are used. Since a 1-to- 
40-GHz spectrum analyzer (without external mixer) wasn't 
commercially available, an m-house 40-GHz spectrum 
analyzer was designed. Fig. 4 shows typical comb lines up 
to 40 CM* for a 1-GHz VCO. A 40-GHz test fixture was also 
designed to test the driver and to adjusl the tuning element 
before sealing it. The input VCO frequency is varied from 
865 MHz to 10.5G MHz and the 38 comb lines are adjusted 
to meet the required counter sensitivity. The input to the 




*f Out - 






^A\ 

RF Input 

Y 



f N " H f 



-vw 



Ci 



Mrcrostrip 
Balun 



R 3 Ra 




Pulse 
Input 
from 
Sampler 
Driver 



Hybrid 
Circuit 



Fig. S. 40-GHz sampler used in me 5356C Heart is a thm-titm 
nybnd ctrcutt. fl, and R? are chosen to optimize bandwidth 
and dynamic range 



APHIL 13B0 HEWLETT-PACKARD JO UK V 17 



)Copr. 1949-1998 Hewlett-Packard Co. 



sampler driver is almost constant since the power amplifier 
is working in the saturation region. Therefore, the eomb 
lines are insensitive to power amplifier variations and 
temperature. 

Sampler 

Fig, 5 shows a schematic diagram of the sampler. It con- 
sists of a thin-film hybrid mounted in an aluminum pack- 
age. Two versions of the sampler are used. The 5356 A/B 
sampler is the same as the one in the 534 3A Counter wiuV 
nut the thin-film buffer amplifier. 2:j A The 53 56C 40-GHz 
sampler is the same basic design with si ightly different 
component values. For the 535GC, R : and R 2 are chosen to 
maximize the sampler 1 s dynamic range up to 40 GHz, 

In both versions of the sampler, two beam-lead 
Schottky-barrier diodes are placed on the hybrid across the 
slotted line. This type of diode provides a low. easily con- 
trolled inductance and is easy to mount on the thin-film 
substrate by the thermocompression bonding technique, 

To work up to 40 GHz. the diodes are chosen for 
minimum series resistance, junction capacitance, and stray 
capacitance. The diode capacitance is incorporated in a 
low-pass filter that has a cutoff frequency of 41 GHz. The 
circuit is optimized for low SWR up to 40 GHz using an 
in-house OFSNAP computer program, Fig. 6 shows the 
relative sampler conversion efficiency up to 40 GHz. and 
Fig. 7 shows the return loss up to 40 GHz. Four experimen- 
tal setups w r ere used for these measurements: 1.5-2,4 GHz. 
2-18 GHz, 18-26.5 GHz and 26.5-40 GHz. 

The sampler's IF output is designed to be insensitive to 
sampler driver variations. The mint inn in output from the 
sampler driver is enough to drive I he sampler into satura- 
tion. Therefore the IF output is also insensitive to tempera- 
ture variations. 

5355A Compatibility 

The design goal was to make any 5356A/B/C work with 
any 5355A, The interface between these two instruments is 
analog, since the VCO signal comes from the 5;J55A to drive 
the power amplifier in the 535SA/B/C, and the IF comes 
from the 5356A/B C tp drive the IF amplifier En the 5355A. 
To guarantee complete compatibility the following condi- 
tions were established. 

■ The IF output from the 5356A/B/C is insensitive to the 
level of the VCO input from the 5355 A. The lowest VCO 
input power level at any frequency is sufficient to drive 




Frequency (GHz) 

Fig. 7. Return loss of the 4Q GHz sampler. 

the power amplifier to saturation. Thus the output of the 
sampler driver is insensitive lo the 53 55 A VCQ level 
The IF output from the 5356A/B/G to the 5355A is mfR- 
cient to guarantee the minimum sensitivity of the com- 
bined system. The counter sensitivity is defined as the 
53 5BA.B/G conversion efficiency {RF to IF] plus the 
53 55A IF sensitivity- The 535SA IF sensitivity is adjusted 
to meet the required specifications and the 5356A/B/C 
conversion efficiency is tested from 1.5 to 40 GHz to 
assure that it meets the necessary levels 
The input of the 5355A is unconditionally stable so that it 
will not oscillate with any 5358A'H'G. Also, the out | ml t>J 
tin 53 56 A/ 13/C i s u n cond i tiona 11 y s I ab 1 e wi t h any 5 3 5 5 A . 
This is especially important since the IF gain ol I he G< un- 
billed system can exceed HO dB. 



Sensitivity, Flatness, and Distortion 

Since the 535GC is so broadband, there were trade- 
offs to be made among sensitivity, frequency response flat- 
ness, and distortion caused by sampler overload. The bias 
resistor R 2 between the sampler IF output terminals (Fit. 1 . 5 I 
w r as chosen to maximize the dynamic range of the com- 
bined 5356G and 5355A up to 40 GHz, 

Dynamic range is a function of frequency. For the 535tiC 
it ranges from -25 dBm to +5 dBm below 12.4 GHz and 
from -20 dBm to +15 dBm above 12,4 GHz for full accuracy 
(±1 count). However, the harmonic number is correctlv 




20 
Frequency (GHz) 

Fig. 6. Relative conversion efficiency of the 40 GHz sampler 
The IF is 300 MHz and the VCO frequency from the 5355A ts 
7 GHz 



o 
U 




I I I 1 I 1 I I i I 1 I I I I I 1 I 
10 20 30 4Q 

Frequency |GHz) 

Fig. 8. Relative conversion efficiency of the 5356A/B^C up lo 
40 GHz. The IF ss 100 MHz and the VCO frequency is 1055 
MHz. Note the higher sensitivity of the 5356C 



18 BE v. -ARC JOURNAL APRIL T9B0 



)Copr. 1949-1998 Hewlett-Packard Co. 



34 GHz 






=: 


u 

s 

§ 




-20 20 <*0 

Temperature f C) 



BC 



80 



Rg. 9. Relative change of 5356 A BIC confers/on efficiency 
with temperature The IFts 100 MHz and the VCO freque- 

1055 MHz. 

determined for a uider range of input signal levels: -30 to 
+8 dBm below 12.4 GHz and -25 to +18 dBm above 
12 4 GHz, 

The dynamic range of the 5356A can be shifted by using 
one of the HP 8493B-5eries Attenuators to replace the coax- 
ial assembly (see Fig, 2). For example, the 6493 B Option 010 
will make the dynamic range —10 to +15 dBin instead of 
-20 to +5 dBm. The damage level will change from +25 
dBm to +33 dBm CW .mil 4*35 dBm pulse, 

Fig, 8 shows the relative conversion efficiency of the 
5356A up to 18 GHz. the 53.50B up to 2fi5 GHz, and the 
5356C up to 40 GHz. These curves are For25 c C Fig. 9 shows 




(a) 



20 
Frequency (GHz) 



i:> 



-12- 




535GA B 
Specification 




^16^ 






? -20- 
? -24- 

2 - 2fl - 




53568 
356 AjBI 




^ 


Measured 


-32- 


* V*^ 






-36 - 








-40 -I 


I I I I I I I 


I I I I I I I 


—\ — i — \ — \ — i — l — i 



10 



(*» 



20 
Frequency (GHz) 



M 



Fig. 10, (a) Sensitivity of the 5356C>5355A system (b.t Sen- 
sfl/vfly of the 5356A;5355A and 5356B5355A systems In a(( 
cases the 5355A is a worst-case unit 



the variation of the conversion efficiency with temperature, 
A 5 3 55 A that has the lowest IF sensitivity within the 
system specifications is used to test each 5356A B C. Fig. 10 
shows the combined sensitivity for CW and pulses. 

Acknowledgments 

The author would like to thank all members of the hybrid 
department of the HP Santa Clara Division, espe: 
Kathy Luiz, who assembled the original thin-film circuits 
The 5356 product design was accomplished very effec- 
tively by Keith Leslie, Special thanks are due Jeff Wolf- 
ington and A! Barber for their constructive criticism dur* 
ing the course of this project. Many individuals from the HP 
Santa Rosa, Stanford Park, and Microwave Semiconductor 
Divisions deserve credit for their help and constructive 
discussion, especially Young Dae Kim of Stanford Park for 
his help in designing the high-pass filter for the 5356A 
Option 001 The product introduction of the 5356A/B was 
handled by Martin Neil, and of the 5356C by Larry Johnson 
and Doug Nichols, Service engineers were Randy Goodner 
for the 5356A/8 and Joe Dore for the 5356C. Production 
engineers were Bob Of fermann for the 5356A7B and Art 
Bloednrn for the 535(iC, Special thanks are due to Luiz 
Peregrine for his continuing encouragement. The author 
would like to express his appreciation to Roger Smith, 
microwave section manager and Ian Band, engineering lab 
manager, for their support and interest in this project, 

References 

1. G,R. Kirkpatrick. R.E, Pratt, and DR. chambers, "Coaxial Com- 
ponents aruf Accessories tor Broadband Operation to 26.5 GHz," 
Hewlett- h i kard Journal, June Wfl 

- | Merkelo, M A dolu-Zu-CH/ Thm-Rlm Signal Sampler for Mi- 
crowave Instruraentation/' Hewlett-Packard [oumal, April 1973. 
3 A Bologlu and V,A, Barber, * Microprocessor-Controlled 
Harmonic: Heterodyne Microwave Counter also Meai 
Amplitudes/' Hewlett-Packard Journal, May 1978 
4, A, Bologlu, this issue, p. 20. 

Mohamed M. Sayed 

Mohamed Sayed joined HP's Micro- 
wave Technology Center in 1973 After 
working on microwave silicon and 
GaAs FET transistors for two years, he 
joined HP's Santa Clara Division, and 
since that Time has worked on micro- 
wave counters Born in Egypi. he re- 
ceived hts BSEE and MSEE degrees 
from Cairo University and his PhD from 
Johns Hopkins University in Baltimore, 
Maryland He has taught at Cairo, 
Johns Hopkins, and Howard Umver- 
s ties, and is currently teaching a\ San 
Jose State University Before joining 
HP. he spent a year doing research on 
solar cells at the University ot Delaware, He has published papers in 
the field of microwave measurements, microwave transistors, and 
solar energy He's a member of IEEE and is active in the National 
Alumni Schools Committee of Johns Hopkins University Mohamed is 
married, has a daughter, and hves In Cupertino, California. He is 
currently attending Santa Clara University to obtain h»s Master's 
degree in engineering management. In his spare lime he Ifkes to read 
and travel 




-380 HEWLETT-PACKARD JOURNAL 19 



)Copr. 1949-1998 Hewlett-Packard Co. 



A 26.5-GHz Automatic Frequency Counter 
with Enhanced Dynamic Range 

A new sampler provides higher frequency coverage and 
10 dB greater sensitivity than previous designs. 

by Ali Bologlu 



DJRECT-CGI\\ T T1NIG FREQUENCY COUNTERS are 
restricted by the .speed of today 's logic; circuitry 
to max i muni frequencies of 5Gfj MHz or so. Con- 
sequently, automatic microwave counters must employ 
some method of down-conversion to ex I end counting into 
the gigahertz range. Traditional techniques, such as the 
transfer oscillator and heterodyne techniques, were 
supplemented by the harmonic heterodyne technique with 
the introduction cd the I IP 5342A in the spdngaf 1 978. i The 
advent of the microprocessor made this technique possible 
along with a significant reduction in instrument cost. 

A new microwave frequency counter, Model 53.4.3 iA, 
niLikes its own contribution by extending the frequency 
range to 26.5 GHz and improving sensitivity and dynamic 
raiige by about 1 lid hi across the band. Furthermore, features 
have been added, making the instrument more system- 
oriented. 

System Architecture 

The block diagram of the 5 34 3 A is very similar to that of 
the 534 2 A [see reference 1), Besides software, the major 
changes are in the sampler area, which will be dealt with in 
detail later in this article, The operating algorithm is as 
follows, The multiplexer selects the main oscillator output 
and the main oscillator frequency \\ is swept from 350 MHz 




Fig. 1 . Model 5343 A Microwa ve Frequency Counter provides 
high sensitivity and automatic amplitude discrimination in CW 
frequency measurements to 26.5 GHz Offsets and scale fac- 
tors can be entered via the front panel. 



to 300 MHz in 100-kHz steps. The offset oscillator fre- 
quency f 2 is maintained at fj - 500 kHz by a phase-lot :.kn.l 
loop, When the IF detector indicates the presence ol an 
IF signal in the range of 50 MHz to 100 MHz the synthesizer 
stops its sweep and the counter starts its determination of 
the harmonic number N + The pseudorandom sequence out- 
put switches between the main oscillator and the offset 
oscillator and between counters A and b\ Counter A ac- 
cumulates f IF1 and counter B accumulates ffe Zt The 
pseudorandom sequence is then disabled, the main os- 
cillator is selected and the frequency f- t is measured by 
counter A to the selected resolution. The pseudorandom 
sequence prevents any coherence between the switching 
rate of the multiplexer and the modulation rate ol the KM 
that might be present on the input signal. Such coherence 
might produce an incorrect compulation of N. Finally, the 
harmonic number and the sign pi the IF are computed and 
the input frequency l x is computed as follows: 

fie = Nf 1 ! - l jF1 ( f IF , < i ]F1 | 

f x - N^ + f IF1 ( f IFZ > f m ) 

where N = f ™ " ^ 

M ~ *Z 

It has been shown- that the length of the pseudsorandom 



-20 r 



^25 



□j 

T3 




10 15 20 

Frequency (GHz) 



30 



Fig. 2. 5343A sensitivity 



20 HpA-l Ft" PACKARD JOURNAL APRIL 1980 



)Copr. 1949-1998 Hewlett-Packard Co. 



sequence required to tolerate frequency modulation on the 
input signal is given by the expression 



P^64 



m 



Thus to allow the counter to tolerate HI MHz peak T 



Pulse Input 

from 

Sampler 

Driver 



Sampler 
Subassembly 




Diode. Beam 
Lead 



1 kit 

1 



100 pF 



+ 5V 



IF Out 



22 kit 



100 pF 



RF Input 



1 001 1 10011 

AM, + N " N t Wr 



• H f H • \ 

1.8pF=^ iBpF 

10011 10011 Microslr 

Balun 

'> O vw i 



15011 
10011 



Pulse 
Input 
from 
Sampler 
Driver 



1 



Fig. 3. The principal design contribution m the 5343A Mi- 
crowave Counter is this new sampler, a refined version of 
previous designs A thtn-fttm buffer amplifier improves the 
impedance match between the sampler output and the first (F 
amplifier 



the input signal with Af = 500 kHz< the P value should 
exceed 25,600, Since P = 2 m - 1 where m is the number of 
shift register stages in the pseudorandom sequence 
generator, a 15-stage shift register would be needed to gen- 
erate this sequence. It is obvious from the expression for P 
that the more FM one wants to tolerate the longer the se- 
quence has to be. which in turn affects I he counter's 
surement time. 

The 534 3 A has three different sequence lengths of Tl ms, 
360 ms, and 2.2 s. The corresponding FM deviations the 
instrument tolerates in the automatic mode are 6 MHz. 20 
MHz, and 50 MHz peak to peak, respectively, These limits 
in fact only apply when the modulation rate is synchronous 
with the pseudorandom sequence, Since the modulation in 
microwave communication systems is usually either data 
or voice, the probability of synchronization is very remote. 
Consequently, although the deviation may be large, the 
signals may often be measured by the 5 343 A using the short 
sequence length, thereby making acquisition times faster. 

New Sampler Improves Sensitivity 

5343 A sensitivity is shown in Fig, 2. The main con- 
tributor to this improved sensitivity is a new microwave 
sampler, which is the only microwave component in the 
instrument. Operation of the sampler is similar to the sam- 
pler used in the 5342 A f l t he main difference being the use of 
a thin-film buffer amplifier to provide a better impedance 
match between the output of the sampler and the first IF, 

In this sampler structure (Fig. 3), the sampling pulse 
couples to the slotted line through a microstrip balun that 
generates two opposite-polarity pulses to drive the sam- 
pling diodes. The down- con verted signal is taken from two 
isolated resistors to the second substrate in the structure. 
which is the buffer amplifier, Resistors across the slot are 
w±v\\ io absorb secondary reflet: t ions introduced by the 
sampling pulse. The input structure forms the essence of a 
low-pass filter with an effective cut-off greater than 26.5 
GHz. This structure provides an input return loss as shown 
in Pig. 4. 

Front-Panel Inputs and Controls 

The 5343A has two inputs, one Ljoin^ from 10 Hz to 520 
MHz and the other from 500 MHz to 2ft, 5 GHz. The right- 
hand side of the Innnl panel deals with input signal channel 
selection and sample rati- 1 nntro] of the measurement The 
left-hand side ol the front panel enables the user to do data 
manipulation by keyboard control of the processor. Instruc- 
tions for doing this are on a label that is affixed to the 
instrument top. 

The panel layout is in algebraic notation, thereby making 
pane! operation closely resemble remote programming via 
the HP Interface Bus (HP-IB*). When the instrument powers 
up it is in the auto mode with 1-Hz resolution. As the user 
selects other resolutions, insignificant zeros are truncated. 
Display digits are in groups of three to facilitate reading. 

In case the user wants to bypass the acquisition cycle of 
the algorithm, a manual mode of operation is available, In 
this mode the user should know the unknown frequency 
within 50 MHz and enter ii via the keyboard. The counter 
then acts like a receiver making frequency measurements, 

Offsets can be specified from the front panel. Any be* 

ifHate'Wflfi AN5lrtEEE4flB*t978 



APRIL 19&0 HEWLETT-PACKARD JOURNAL 21 



)Copr. 1949-1998 Hewlett-Packard Co. 



Or 



£2 

TO! 



-10 




2000.0 



26500 



Frequency (tAHz) 




AN Bologlu 

All Bologlu has been with HP for fifteen 
years and has been project manager 
for microwave coumers since 1970, 
He's contributed Lo the design of many 
HP frequency synthesizers and micro- 
wave counters, most recently the 
5343A. All received BS and MS de- 
grees m electrical engineering in 1962 
and 1963 from Michigan State Univer- 
sity and the degree of Electrical En- 
gineer from Stanford University in 1965. 
Born in Istanbul, Turkey, he's married, 
has three children, and now lives <n 
Mountain View, California. He plays 
tennis, enjoys water sports, and 
coaches a youth soccer team. 



where m is the multiplying integer, x the measured fre- 
quency and b the offset. 



Fig. 4, Return loss of (he 5343 A sampler 

quency offset can either be subtracted from or added to the 
measured frequency, fn the auto offset mode of operation 
the counter holds the initial measurement and then dis- 
plays all succeeding measurements as deviations about the 
ini tied reading. Frequency readings may also be multiplied 
by integers and offsets then added to the product, in effect 
solving the equation 

V - mx + b 



Acknowledgments 

I would like to acknowledge the efforts of John Shing, Jeff 
VVolfington, and Keith Leslie fur their important and timely 
contributions to the 5343A. 

References 

1. A. Bologlu and V.A. Barber, 'Microprocessor-ContioJied Har- 
monic: Heterodyne Microwave Counter also Measures Ampli- 
tudes/' Hewlett-Packard journal, May 1978. 

2. L. Peregrine, » r A Technique that Is Insensitive to FM for Deter- 
mining Harmonic Number and Sideband." Hewlett-Packard Jour- 
nal. Mav 1978. 



SPECIFICATIONS 
HP Model 53-43A Hicroweve Frequency Counter 



FREQUENCY RANGE: 


Inpui 1 
frfXI MHr-Jfi 5 -GHz 


SENSITIVITY- 




BOD MHz 12 4 GH* 


iadE^r 


12.4 GHz-lE &GHz 


M 0Bffl 


U.'tf .',H: $| IQHj 


£.3 dfim 


MAXIMUM rMPLTT --.:&! 


DYNAMIC RAJMJE: 




500 MHz. 12.* GHz 


40 «a 


12.4 GHjIB* GHz 


3t oH 


lF-0GHi-2a5 GHz 


B -h 



DAMAGE LEVEL: - » nBm peak 

IMPEDANCE: St. nnra, nmir^i 

CONNECTOR: f<PC 1 1 tjjIq *nh npLar ',5MA mnwoitftB), 

SVffi: 

H» MHz-13 GHz - ,2 1 typical 

*0 GH;-l0GHr J i l r -,r^,i 

■IB GKi-aS-5 GHi 
COWPHMQ: dt 1c load, jr Id FffltFtipajti 
FM TOLEHAMCE:f,wrtr?i snWct3C+8 on tear panel Bar modLKalion ralm irari dc 1n TO MHr 

WIDE. 50 MHi p-p wDnL^nio 

NORMAL K MH; p-p wtnt emsm 

NAflHOW 6 »Hi p-p Aural case 
AH TOLERANCE Ar, v itKjjLialic# inrt* ^irudntf **i" nmmijir r^ntf \tv& H flUl leti Ihan 

(he s«r;niiv(t> soecrticaiipf 
MODES OF OPEflATIOH; 

AUTOMATIC Cbunlar HLrtn«na-1caity K3Ullfii «1Q iU-plttys hqh»Dl in-.^ ■ . ■. ■ 
=C-v Vvrtv rangr 

MANUAL Cenlor ^aqcmnrv RTf-prM 10 Waftfl : Bill Mi*.: u' i-ut rjglua 

AtouemoN TIME 

Ai.i-ovfiTIC MODE Na/row FW TOmj w of&l C35£ 
♦iormaJ FM £30 rn* W3H case' 
Wide FM J4S WhJfal ta5S. 

MANUAL mode dc <*m ■?**• ireqvenc^ ertwee. 
AUTDMATfcC AMPLITUDE OliCRlMutATION- 

AulOrnfflicaJljf rF.*aiur« hne : 3ij>es1 Of E* EJprala treses, prp^ibnn. All sigrjl i= 
6 dB ilypicali above-*** *iOiy 3 - * ir. > 50U VM: 20 -ih j £■---.■•• ar* '-o-v 
500 M^.afc.E, GH; 



Input 2 

FREQUENCY F.ANGE. "1 Hi II' 523 MHi Evoct Cpi.nl 

SENSITIVITY 50(1 10 Hi in 520 MHz iS mV rnis 1 1/11 10 Hi -s 25 MH2 50 .TV M 
IMPEDANCE 5*lBcltiU(v I Mil iU nF :* firm nrnHnal 
COUPLING- tfc 

CONNECTOft: i &a ENC ramala 

MAXIMUM INPUT SC-id 3 5 Jnm -2a H an: i. ... K , , gM jfD4BCi*l * Mil StlL! V 
f, ■■ '.ins 

Time Be se 

CRYSTAL FHEQUENCV: '0 MhU 
5T*fl>LnT: 

AGING RATE l ■ ip " p»r mcir^ 

SHONT TERM . 1 . TO " r * Ion Eil ime 

TEMPE RATuFlE - I ■ 1 % ' e o Y «f J ne f ar^jt 0"C to 5C' C 

LINE VARIATION - 1 ■ 10 " ~ •& 10*. (yiflflde ^m nmr^na. 
OUTPUT FREQUeNCY ir MH: -2 aV square win |TTL cnrnraliliiii I *■'.' r 

Id-dobV. ;nca MH | Jv^ilafM Irpm t ejy pari 1 E+JC 
EXTCflNAL TIME 8ASE. Hoc-jmcs m Mri? B W peai-IO-JjeBh. 1H 1 * w»e ji dc 

We.t t:d i Hi ^ia r eEf papal gfjc corriecipr 5wH£h sfii«1£ cfllief iternil pr ox 



Optional Tim* Base 
Option 001 

MJliar KT pin.rafre an oven-CO^npllBd C^sia 

dnLa shaerl I, Star rd^i.irj o b^tisi ±l^ji2L-> and Icnc^ai r<i r oa 

CRTSTAL FREQUENCY: l<] MHr 

STAB4UTY: 

AGING RATE. 5 - 1Q ' '" flay atl»r ?4-nrwi *air7.-,ip 
5HCST TERM 1 - ■"■: vn !□' 1 s flj.j :r.e 
tEMPtFtAtUHE ■ .* • 1 " 9 tf*w iria i anc« C C to fifl'C 
.INE VARIATION ■ > - 1[T 1B 1* ^QV fining* fri*n nci™T* 

WAR**-1JP: 5- 10 3 3i' -ng; vai.je £0 rrtnLHes. ata t.'n 



HUD i^ Bfisldg vnftxi 



OfgitaMo-Analog Convener 
Option 004 

an* i^niiy ip Kinvfl an^ '" -■ 

utjiul A dipp-jy (f ;<J0 tiiodPCHS 0V DuituL. ° 



ACCURACY: ■tiT'.' -UilnV C: i IrnT. :■!■■ i, , 

CONVER5SDN SPEED; - 40 Hi 10 +0 O't** til Ml tiaJo rrnding 

HESOLUTIOH: IB mV 

OUTPUT. 5 mA. Irnpadantsi ■ 1 U ahm 

CONNECTOR": Type BNC Ip-raln nr rear panel 

General 

ACCURACY' -1 rc'ini -nrr^ nase efro 

RESOLUTtOHr Ffttrtt^rtsl ppsMjullon sslBCl 1 Hz ID 1 Mtu. 

RESIDUAL St AaiLITV 'A'har, tftirrler a/ic SOjrce uba curhniLn- limeluiao j cojivlei uaas 

fliramal liQ^e 1 Ka^l I* 1ilTietJE-E*i a >: 1 D ] 1 -rna lypKau 
OISPLAV: It-dgn LED *afd4y, i4L',ono;iin.< lo iesI GHr. MHz, kHi a pj Hi 
SELF-CHECK: Seie-.-IsC ftBBI Ircil pnV pjilitvin^ni MnjnurHS t& MHj In' rtEDlurar 

C^s&an 
FftElQiJtnlCY OFFSET: Scleclnd Itom Irani pqnol pi.snhnnrYm l>silay«] |?flqy»ncy * rflf- 

Hl D- r s'Me'te! vaiLC Id 1 Hz -&d Jl.or 
MULTIPLY nOUTlNe Sewi^j l^on «:am-?arvol ziLLhbuflcKia Muas.irKl Inacuancy ^ 

raut^liBd hy n't nfig&t ,|. |(\ 99 THrr^sC; car. bo addnd or clt' irmn f||f r r- , - r 



ll SS0 MHz ReadOUl O^ rho 11 

it G^raacl ctjfiuiw Ic pnotffflt >50 *i£ 
ncnls wnvn rn r,wptori itkxI? 
^i. n!-ni iltnr AUci^s inlefaca TO 



TOTALIZE 

... HP-IE 
EXTERNAL TFUQOER: TL i-jcpo >ow 

fHtir-Liai-cl (Xtnnecftir A inhale 
SWEIr? MODE :■(«'« IIDn-. 

incepc mr a'.t^l =Wp. 3rd n 
SAMPLE RATE. VanacMa Iron 

whpn holcb. diapaj incahr r ily 
IF ODT: flcar p»n«l BNC wnneaor c*nyidas E5 MHZ iff 52S MNz dulput crt 

i^ji'v-i'isL' nicriraavn vcjnal 
OP-ERATINQ TEMPERATURE: C^Z In SflC 
P&WER PEaUIREHEWTS: 1 00 ^0.230:240 Vnra, -6%. in-. ^.^6 hi |D0V5 

Accessories furkished: Fi«™r c=re ia& ctt 

Sll£ 113 rrnm ■ 51:j itt W JH mm £> iS'.. « 9^ i 19i* n 
YVEIOHT. N« 5 1 kg t20 IIM Sl^ppj/Hj 121 *q 13S lp; 

PRICES IN U.S.A 53-J2A Mcuwavs frecuarcy Gqcfi-^r $5 200 Gpi*ir. 0u' 
S1ef. = ly T ime eate iSOO Opl*l CO* OigflxMo Anav>j CwvEfi*-. 5350. 
Oil a^rlad ffputOu&hJj jHP-|B!, S3K 
MANUFACTUPdNG QlWSlQN- chWT* CLAFIA OWSDN 

5991 Sta@n§ Ofiei. Sculviin] 
5e'ira Cla.'i. Califnrr • • 



22 HEWLETT FA.CKARQ jOl.RWAL APRIL + 9BC- 



)Copr. 1949-1998 Hewlett-Packard Co. 



Microwave Counter Measurements 



by Richard F. Schneider 



FOR CONVENTIONAL Pl'LSE RA he major 

parameters that must be measured are the average 
burst frequency, the pulse repetition frequency 
U*RF)« the pulse repetition period (PRP). the pulse repeti- 
tion interval | PKl ] , and the pulse width. These measure- 
ments are automatically made by connecting the equi pment 
as shown in Fig. \, To measure the average burst frequ> 
the user need only assure that the peak pulse power is 
within the counter systems] tions. I fsually a test port 

is available in the form of a directional coupler built into the 
radar system, or a test horn can be connected to the 535hA 
B'C Head for measurements after the radar system has beam 
"buttoned up", SUCh as on the flight line. Since the gating 
signal for the 5345 A Counter is generated by the 5 
Converter, no auxiliary equipment is required. This gate 
signal, as described in the article on page 3, is about 30 ns 
shorter than the RF burst to avoid turn-on and turu-oti 
transients. The measurement is made by selecting the 
plug-in and external gate functions of the 5M5A Counter 
and the pulse mode of the S3S5A Converter. The average 
burst frequency is then displayed on the 5345 A Counter, 




5356A B C 
Frequency Converter Head 



1.5 to 40 GHz 

Radar 
Transmitter 



Fig, 1, Test setup for conventional radar measurements {av- 
erage burs! frequency, putse repetition frequency, pulse 
repetition period, puise repetition interval, pulse width). 

Since the IF is detected in l he 535 5 A Converter plug-in 
and is available on the rear panel PULSE OUT COanei tor, this 
signal can be used to make the other measurements. PKI-' is 
measured by setting the n345A Counter function switch to 
IREQ A after adjusting Channel A to tin* proper levels, I'KP 
is measured by simply suiting the 5345 A L'ounfer I unci ion 
switch (n hkkiof) a. Pulse width is measured bj setting I he 
iuiK Hon switch to TIME INT-ATOEk tta input to COMMON, 
channel A slope to -, and channel li slope In + < PR] is 
measured b\ reversing [he A and H channel slope polarities. 






Oscilloscope 



Gate Control 
Input 



T 



22 ns 
Delay 



Pulse Out 





5355A 


5345A 


Automatic 


Counter 


Frequency 




Converter 



53S6A/B/C 

Frequency 

Converter 

Head 



J 



53S9A Time 
Synth & 



Ext 
Trig 



As Narrow 
as 20 ns 






Fig* 2. Test setup for frequency profiting of an RF curst. 

Since the IF is limited before detection, pulse width mea- 
surement accuracy is dependent on the rise time and the 
pulse width. For slow rise times, the pulse out (and the 
measured width I will probably be longer than the width 
defined by the time interval between actual 50% points, 
while lor fast rise times it will be within 3% of the actual 
pulse width. This occurs since the pulse out signal starts 
iitu.\ stops when the input RI-" level exceeds AkG system 
sensitivity, jitter can also occur in ihe pulse width inea- 
SurenieiiJ it Ihe pulse mudulation is not coherent with the 
carrier, This . ,i n i a use the IF envelope to vary by one period 
ot ihe IF, or in the worst case, as much as ± 1 ns. \ lowever, 
this jitter is automatically averaged out if time interval 
iging is used. 

Frequency Profiling and CW Measurements 

I requency profiling nl an KI/ burst is done using a time 
synthesizer such as the III 1 &359A, as shown in Fig. 2. I lere 
the 5359A 'time Synthesizer is triggered by ihe pulse 
put signal from the S&ftsA Converter plug-in. The 535 9 A 's 
delayed output pulse, a -l.n-volt signal, is used to enable 
\ ( .uunter's gate control Input. The uidth oi I his 
externa ! gate signal determines the gate lime of the 5345 A« 
The delay is incremented afler each measurement so that 

measurements age made at successively later limes within 
the RF burst. Fig, 3 shows the frequency profile and spec- 
trum of a 250-ns wide chirp pulse. The chirp has a 
bandwidth of 200 MHz; it was generated by rampirm a 
Voltage-controlled oscillator (V€0) and synchronously 
pulse modulating its output, i or chirp radar applications, 
the linearity ot the ramp is paramount, while Doppler 
radars E$£}u$fcti niiniaiaJ I'M on (he burst, These measure 
merits can be made to L00-1 Iz resolution with external gates 
as narrow as 20 ns. 

I in [ AY measurements, such as on a C AV radar, a STALO 
(stabilised local oscillator). oi L . ( il >! If >!• whereat oscillator), 



APB1 L 1 980 HE WCETT PACK A RD JOUflt 2 3 



)Copr. 1949-1998 Hewlett-Packard Co. 





J 

1 






■ 

ii 

5 £ 

« LL 

C 


i 






[* 250 ns * 





LV, 



i 



50 MHz 

i i 



10 dB 



10 55 MHz 

Fig. 3. frequency profile and spectrum of a 250 -ns chirp 
pulse, Profile can be measured using a 20-ns gate 

frequencies are measured to 1-Hz resolution in one second. 
Also, the average frequency of a fully loaded microwave 
carrier with traffic can be measured, since the counter sys- 
tem's specified FM tolerance is 15 MHz p-p (80 MHz p-p in 
the special FM mode), 

VCO Measurements 

Transient measurements needed to evaluate y VCO are 
settling time and post-tuning drift, as shown in Fig, 4. The 
settling time is the time (t st ) required for the output fre- 
quency to enter and stay within a specified error band 
(±f st ) centered around a reference frequency (f| after appli- 
cation of a set input voltage. Post-tuning drift is the maxi- 
mum change in frequency (±f pt< i) during the time interval 
t 1 to U, where t t is a specified time after t , the start of the 
step input voltage. These measurements may be made with 
the equipment shown in Fig, 5. 

In this measurement, the tuning voltage pulse generator 
is set to the necessary step voltage levels to drive the VCO. 
This generator also provides an external trigger to the 
5 35 9 A Time Synthesizer, which synchronizes the 5345A 
Counter by generating a gate control input signal The time 
ft r ) that it takes the VCO to reach the reference frequency is 
then set into the time synthesizer as a delay, and the width 
of the synthesizer output pulse is set to an appropriate gate 
width for the measurement. Then selecting the automatic or 
manual pulse mode of the 5355A Converter plug-in causes 
the counter to display the VCO reference frequency, 

The start of the reference frequency step may also be 



VCO y 

step/ 

Generator 

Input 




MTO) 



t f (From) 



Sync 



i 



.1 




tr ll 



Fig. 4, Transient measurements needed to evaluate a 
voltage-controlled oscillator (VCO) are settling time and post- 
tuning drift. 

observed by stepping the time synthesizer delay by one-half 
the step generator period. In this manner, the absolute 
levels of the VCO step generator may be adjusted to set the 
initial and final reference frequencies. Next, the delay is 
decreased until the displayed counter frequency exceeds 
the specified error band [±f sl ]. This delay defines the set- 
tling time, In a similar manner, the post-tuning drift may be 
measured by observing the change En frequency from delay 
time t : to time t 2 . In both measurements, changes of fre- 
quency may be easily observed by setting the counter to 

Gate 

Control 

Input 



5359A Time 
Synthesizer 





S355A 


534SA 


Automatic 


Counter 


Frequency 




Converter 




t 



Ext Trigger 



Pulae 

Generator 



Tuning 
Voltage 
Pulser 



Fig. 5. Test setup for VCO measurements snown in •Fig. 4 



24 HEWLETT-PACKARD JOURNAL APRIL IfBS 



)Copr. 1949-1998 Hewlett-Packard Co. 



11J9 - 






r - 



10.23 



W 



-f— h 



Time (US) 



I I 1 I I I I I 

1000 



Fig, S. Settling time measurement on a VCO 

display deviations from the reference frequency. This is 
done by subtracting the reference frequency by entering the 
last measurement into the 5355 A Converter as a frequency 
offset. 

For large frequency steps, the 5355A Converter will have 
to reacquire the signal when changing from ihe initial to the 
final frequencies- This can be prevented if the initial and 
final frequencies fall within the 5 3 55 A IF bandwidth for 
two harmonics of the 5355 A synthesizer frequency that is 
used to do wn- convert the microwave input signal (see arti- 
cle, page 3). For instance, if the VCO is stepped from H to 1 2 
GHz, a synthesizer frequency maybe found to satisfy both of 



these frequencies. By using the 5355A's diagnostic mode 9, 
the synthesizer frequency may be set to 1025.2 MHz. The 
8th harmonic is 8201.6 MHz, and the IF frequency is 201.6 
MHz- The 12th harmonic is 12.3024 GHz and the IF fre- 
quency is 302.4 MHz, which is still within the limits of the 
IF bandwidth. The actual IF cen be observed in diagnostic 
mode 10. 

By adjusting the synthesizer frequency and the initial or 
final VCO frequency, it is possible to nearly center both IFs 
so maximum deviations can be measured. It is possible then 
to observe frequency transients whose excursions are less 
than one-half the IF bandwidth. The size of the step from 
initial to final VCO frequencies is ultimately limited by the 
bandwidth of the 5356AB/C Frequency Converter Head 
being used. 

A settling time measurement of a VCO is shown in Fig, 6, 
Fully automatic measurements can be configured using the 
HP-IB to control the time synthesizer [delay generator), 
plotter, tuning voltage pulser, and digital voltmeter. Other 
VCO measurements* such as frequency accuracy, frequency 
range, frequency linearity, pushing and pulling factors, 
modulation sensitivity, hysteresis, and warm-up frequency 
drift may be easily made in the CW mode. 



correction 

.- the caption thai woe ■ ■ Q& Marcr ■•■ 

Fig. 7, Calibration oscillator The LC tank circuit alternately 
turns off each transistor so the output power is restricted to l Q 2 RI4 
l Q and R were chosen to make this equal to -10 dBm 



Laboratory Notebook 



A Flexible Software Development Technique 



A common problem in the development of mi crop ro eessor- 
based instruments is that there comes a lime when fheso/twurehas 
ro be committed to firmware in the form of read-only memories 
(ROMs). Generally the software development engineer delays 
committing to masked ROMs as iong as possible to avoid the costly 
musk changes that would be required should "bugs'* or tiSce&SOry 
modi/ications appear in the future. The software development 
technique used for the 53 55 A Automatic Frequency Converter (see 
article, page 3} is flexible enough to ailoiv an early commitment to 
ROVfs Without being penalized for changes later on. This technique 
can be used in any instrument where the ROMs urc not coded to full 
capacity. 

The technique also offers advantages once the instrument is in 
production. Generally, it is possible to implement a relatively 
complex software modi f hot ion by changing one correction ROM 
insipid of all ROMs. If the Correction ROMt -an herv ih an 

EROM (erasable ROM], then Mir production change can be im- 
plemented without incurring a long lead time for a new masked 
ROM. 



To explain the technique, the 53 55 A ran be used as a case 
history. Approximately one year before product release, it was 
evident tiiatit would take 9K to 10K by ten of microcode to complete 
the 5355A. Our microprocessor board bud two 24 -pin sockets to 
ui ■■ ommodate ROMs. With the ROMs available at the time, the 
microcode could hare been programmed info HKxM and 2KxB 
ft< )\J.s, thus filling up bath ROMs. For a slight incremental cost, the 
2Kx8 ROM was replaced with a 4Kx8 ROM, making the total 
available microcode space \2K bytes. The extra 2K bytes of ROM 
become valuable space to accommodate corrections for theSK xti 
ROM microcode. 

Unlike the 4K k8 ROM, the »Kxti ROM could not be simulated 
with a single pm-.lor-pm-compufibie EROM. It was therefore neces- 
sary to order a masked ROM eight monfhs before product release. 
hi anticipation of future microcode corrections, any software 
routine larger than 250 bytes was partitioned into relocatable sec- 
tors with Coding taking Vlp 250 bytes or less. 

To make a sector relocatable, one ur more jump instructions were 
required. The jump instructions have a tixed location within the 



APRIL 1980 HEWLETT- PACKARD JOURNAL 25 



)Copr. 1949-1998 Hewlett-Packard Co. 



4K x8 address space, Thus, whenever □ correction andSor modifica- 
tion wg s n eeded t th e Opera n ti add ress cadi* of t he appropriate jump 
instructions was changed from one pointing to the BKxB ROM to 
one pointing to some unused address space within th?4K xS ERGM 
(see example in Figs. 3 and 2 on line 15}. If necessary , an entire 
sector can be redone. On the average, however, a correction will be 
needed half-way into a sector. Fallowing the corrected code, an 
extra jump Instruction is added to gel husk to the usable part of the 
sector j'n the original 8K xB ROM fsee Fig, 2 line 24 j. Assuming 2K 
bytes of correction space and 250-byte relocatable sectors, one can 
expect 16 corrections f i25 bytes on the average I before the memory 
is filled. In the cane of the 5355A, many routines were much 
smaller than 250 bytes. Therefore, [he 2 K- byte correction space 
was adequate for mare than 16 corrections. 

With this technique only one version of the 8Kx8 masked ROM 
was needed. When the time came to produce the instrument. (he4J£ 
bytes of software cade could he implemented and shipped in either 
a 4Kx8 EROM or a 4Kx& BOM. The chain- between the two was 
determined by JJ how 'final" the software appeared to be, and 2\ 
the cost tradeoff between the higher EROM unit price and the mask 
charge of the ROM. For the 5J55A. the break-even paint between 
EBOMs and ROMs was one production run. H was therefore de- 
cided to buiid the first two production runs initially witlt EROMs 
Masked ROMs were ordered with sufficient lead time to allow a 
last-minute ^placement before shipping fbe instruments. 



Routine Call 




<■) 



000: 

0053 
DO 04 

00 95 
DO 06 

I..0C? 
0006 

'i ..- 
010 
CAM 

uii: 

GDI I 
00 1* 
0015 



dftlb 
GOT? 
Dfllfl 



0021 
0022 
4023 

4)024 



0&2A 

(b) 



Correction ROM 
or EROM 



Firm ROM 



* 08-12-75 FCLE rtAHE . hBEa 

■ ftfi£fl UF CIRCLE CALCULATION 

* USES HATH PACK SiniLHU TO H-P POCKET £ALCULflTDR 

* SUBROUTINE CALL i JSR CiRCLE 

* EhTPY ftEQUiREHENTS- RADIUS IH 1 T t FtL I*E|j 

- E*[T STATUS: r.X REGISTER CONTAINS RESULT 



0160 
60e0 



34*1 
S441 
5**2 
5443 



7E CIRCLE 



29 



7328 

'329 60 

7329 50 
7321* 21 
7328 CE 
?32C 1 
732D 6 
73 2E BO 
?3ZF 50 

7330 00 

7331 BCV 
7332 
7333 
7314 

7335 50 

7336 f5 
713? CE 
7I3& 60 
733* 8t) 
733A BE- 
7336 54 
713C 00 
7331' Bt 
73 3E 
733F 
73*0 
?341 



frl- 



5 



EQU *I60 

eolt itoeo 



QR£ f544i 

J HP ST»RT 



OPC t7124 

JSft FCLR 



j'iR FfiCt 

JSP PfiCt 



LD* tP{ 



JSR FRtL 



jS* FHUL t 



BTfi 

L'.t 



RftDSUS VPPJmBLE Rah ADDRESS 
PS CtikSTflHT PQH ADDRESS 



r ::■..: c hl:-rf*s jJt«ih ** bvte efom 



hUDFESS MITH1H 6K BVTE fiOfl 
CLEJtfl ALL rlATH REu!£TEfi£ 



XXtRftDlUS 

M*+-»flDIU£, YY^RfiMUS 

XX^HsibtljS+RADJUb 

^ : I YV^RAD[US*PflDIUS 

XX^rF I-FflDEUS^ftADJIUS 
PETURH EM& OF SQUTINE 



Shoaid software bugs be discovered in the future, q netv 4Kxfl 
ROM would he ordered. In the event that the4Kx8 ROM runs cut of 
correction space, tiien lite complete set of ROMs will be required. 
At that time, it will be beneficial to clean out the correction space in 
the 4K ROM by changing the jump operand addresses back to the 
8KROM, Note that the example in Fig. 2 has been amply annotated 
so (hat rj correction can he spotted easily. Removing the special 
corrections months or years later is therefore a si m pie task. 

Figs. 1 and 2 show an example of a correction in 6800 micro- 
processor code. Tfre4KxE correction EROM is assigned addns^ h 
$5000 to S5FFF and the 8K ROM is assigned addresses $6000 to 
$7FFF. Note that the correction penalty here is 12 bytes in the 
4K xfl EROM plus about five microseconds far the lump instruct! tin 
at the end of the correction, Hedoing the entire routine would hove 

required 26 bytes. n . . _ _ . 

-nonulo t. r etscnsU'in 



Routine Call 



o) 




Correction ROM 
or EROM 



Firm ROM 



00*1 






■ 


11-13- 


^1 


FJLE NawE 


CJficriF 


OD02 






- 












DO 03 






• 


CIfii!tJnFEfi£Mi:E 


OF CJRCLE CfiLCULflT] 


U0D4 






* 


li.'SeS PIRTH 


PACt 


; 5 1 PILAR 


TO tt-P POCKET CALCULATOR 


DO05 






* 












«(/06 






* 


SCJ&fiflUTI* 


ClftHLE 


007 








ENTPV 


i£bHJ]fEMEHT5 i 1 


iADtUS thtTtMLlIEC 


O00B 






♦ 


EXIT 


STflTUS; 


XK PEGISTER CONThIHS RESORT 


0009 






< 












001 


■jibfr 




Ro&iUS 






»!■*!} 


RADIUS VARIABLE RAhl HD DREES 


001 1 


6 08 




PI 






FOu 


16064 


PI LOHSTflNt ROM ft&&ft£fijl 


□ 012 






- 












001 J 






* 












001 4 


3441 










UPC 


• 5*4 1 


FflKCfi ulI-pE.:? LI THEN *K BVTE EROI 


DOIt) 


5*41 


7£ 


ClUHl 




.nF 


ST ACT 






5H42 


l» 
















54^3 


ii 














»*t« 






- 












00 1 7 






•cccj: 


.1- 




3TAPT CdRf!ECndH CCCCCCCCCCCC 


OOES 






* 












uOI * 


5850 










-3Bt 


»5350 


r^^LLhBLE A5&SE5S UjTHth 4h ERQh 


020 


5950 
5&51 
565^ 


51 

21 


it 


..s r 




JSR 


FCLR 


(1LEMP ALL NATH fiE^il^TERS 


1031 


3§33 
S854 


■2'. 

B9 








LiJrt 


A a 




uC22 


5S55 
5Q56 


?7 








r. 


h <:■; 


^*--- 


0023 


5957 
3B5S 
555^ 


CE 
J i 

',.1 








LDX 


• u^i . , , 




0024 


5B3fl 
56 SB 
58 5C 










,1F- 


(733* 


JUMP Tfl USABLE SECT f OH OF dt *OH 


tO 25 






* 












&026 






♦L 


C$££€€C€ 




EOT HORREi 


&Q27 






* 












OOJS 


7331 










ORG 


*7331 


Af&fiESS uF ijhCOPRECTED CODE 


0029 


7311 
7312 
7333 


a j 

i. :■ 








JSR 


FRCL 


yM*-RAplUS. vir*-? 


0010 


7334 
7335 
7336 


50 

15 








JSP 


FHULT 


w«<-2**AtiiJi 


jC 7 1 


?317 
7338 
7319 


CE 
S I 








LDX 


i>i 




0012 


733A 

733B 
733C 


50 








• : - 


FPCL 


HK+-P1, W4>^«PRCIU£ 


1JU33 


733D 

^73E 
"3 JF 


= ■ 

f,5 








J$fl 


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734 


-■- 








RTS 




BEtURN: EHD> OF CQUT[N£ 


0035 


f34\ 










ENP 







(b) 



Fig, 1. (a) Relationship of the correction ROM to the firm ROM 
for routines that have not been corrected, (b) An example irt 
6800 rrifCfQCOde. 



Fig, 2, (a) Relationship of the correction ROM to the firm ROM 
for a routine that has been corrected (bj 6800 microcode 
example. 



26 HEWLETT- PACKARD JOURNAL APRIL 19&0 



)Copr. 1949-1998 Hewlett-Packard Co. 



SPECIFICATIONS 

HP Model 5355 A Automatic Frequency Converter and 

HP Models 535SA B C Frequency Converter Heads 



Input Specifications 
CW and Pulse Modes 





5S56A 


S356B 


S356B 
Opt- 001 


5356C 


5356C 
Opt 001 


sensitivity: 












i 5^;. 


-20 dBm 


-20fjBrn 




~ 25 dBm 




12.4-1S GHz 


-T5dBm 


- l 5 dBm 




-20 dBm 




16-26.5 GHz 




-15 dBm 


- 1 5 dBm 


■20 dBm 




26 5-34 GHz 








tS dBfn 


-15 dBm 


34-40 GHz 








-10 dBm 


10 dBm 



MAXIMUM INPUT: 












1 5-12 4 GHz 


-5 dBm 


-5 dBm 




- 5 dBm 




12 4*18 GH2 


* 5 dBm 


■5 dBm 




* 15 dBm 




18-26.5 GHz 




-5 dBm 


+ 5 dBm 


* 1 5 dBm 




26.5-40 GHz 








-i£dBn- 


-15 dBm 


DYNAMIC RANGE 












1 5-12.4 GHz 


25 dB 


25 dB 




30 dB 




12.4-1 a GHz 


20 dB 


20 dB 




35 dB 




1B-25SGH2 




20 dB 


20 dB 


35 dB 




26.5-34 GHz 








3GdB 


30 dB 


34-40 GHz 








25 dB 


25 dS 


DAMAGE LEVEL; 


+ 25 dBm 


t 25 dBm 


-25 dBm 


■ 25 cBm 


+ 25 dBm 




peak 


peak 


peak 


peak 


peak 


IMPEDANCE: 


5011 nominal 


50U nominal 




50fi nominal 




SWR (TYPICAL): 












1.5-10 GHz 


- 21 


- 2 1 




• 2:1 




10-18 GHz 


3*1 


:• i 




3:1 




1B-26 5GHz 




<3:1 


- 3:1 


3:1 




26.5-34 GHz 








3:1 


3:1 


34-40 GHz 








•■5:1 


S 1 


CONNECTOR: 


n Mate 


SMA Male 


WG 


APC-3.5 Male WG 






with collar 


WFt-42 


wilh coltai 


WR-26 



5355A 0.4-1.6 GHz input 

SENSiTivr 

MAXIMUM INPUT -5 dBm 

DYNAMIC RANGE 20 dBm 

DAMAGE LEVEL -24 dBm (Fuse m BNC Connector} 

IMPEDANCE 501^ nominal 

SWR 25 1 typical 

CONNECTOR BNC 
S356A OPTION 001 HIGH-PASS FILTER: 

INSERTION LOSS l dB from 1 5 lo 18 GHz. 

tNSEFTTON LOSS BELOW 100 MHz -35 dB. 

General 

IF OUT: Down converted Signal in range ol 80-375 MHz available at 5355 rear panel IF OUT 

connector. dBm -.omina'i level, 
GATE OUT: lo - 1 vol! delected tF signal used lo drive 5345A external gate control input. 

Width ol gate out is approximately 3D ns less than rt bursl width 
PULSE OUT: Detected IF signal TTL levels. TTL low indicates signal present. -1 to OV 

typical into SOU 
OPERATING TEMPERATURE: to 55 C 
WEIGHT: 

5355A 3 75 kg IB lb. 4 az s net 
5356A;B>'C; 0-54 kg (1 lb. 3 oi\ net 
5356A/B/C DIMENSIONS: 27 .4 mm ■ 13B mm - 56 5 mm (1 Q& - 5.43 ■ 2 23 in |, Gable 

length: 1.68 metres 1 66 in). 
PRICES IN U.S.A-i 5355A Automatic Frequency Converter Prug-ln (HP- IB Slandatd). 
S4150 
5356A 1a GHz Frequency Convener Head. SI 300 

Option 001 High Pass Filter, add S 125. 
5356B 26.5 GHz Frequency Converter Head. S1B0Q. 

Option 001 ta-26.5 GHz Wauegurde Input add $600 
5356C 40 GHz Frequency Converter Heed, 52400 

Option 00 1 26.5-40 GHz Waveguide Input, adrt S50D, 
534 5 A Electronic Counter. S4900. 
Option Oil HP^IB. add $300. 

Option 012 HP-IB I includes Programmable Trigger Level], add £1450- 
MANUFACTURING DIVISION; SANTA CLARA DIVISION 

5301 Stevens Creek Boulevard 
Santa Clara. California 95050 USA 



Operating Mode Specifications 
CW Mode 





5356 A/B Input S3 5 6 A ■' B 1 n p u t 
Auto Mode Man Mode 


5355 A 
0.4-1.6 GHz Input 


5356C Input 
Auto Mode 


5356C Input 
Men Mode 


FM TOLERANCE; 


15 MHz p-p BQ MHZ p-p 

(60 MHz p*p m specie- FM Rate; dc-10 MHz 
mode) Rate dc-10 MH; 


Instantaneous frequency must 

nol exceed 0.4-1 .6 GHz 

range 


60 MHz p-p 

Rate dc-10 MHz 


80 MHz p p 

Rate dc-iii' 


AM TOLERANCE: 


Any modulation index provided the minimum signal level is greater lhan the counter sensitivity. 


MULTIPLE SFGNAL 
DISCRIMINATION: 

Itypicali 

ACQUISITION TIME: 

nyp- 


Automatic Amplilude Discrimination 1 AAD) 
Automatically measures largest signal provider! 
signal is 8 dB (typical) greater than any signal 
withm 500 MHz anq 20 cB nypicah greater (nan 
any signal over range 1 5-26.5 GHz 




6 dB within 500 MHz range, 
20 dB wrtNn 1 5*26 5 GH; 

15 dB within 26 5-40 GHz 
(Option 00 1 20 dB wiihm 
26 5-40 GHz) 


B dB withm 500 MHz range 


400 ms 15 ms 
M 1 s in special FM mode) 


■ 1 ms fFreq ^flOO MHzj 

5345A Ga'e Time - 45 ms 

iFreq BOO MHz) 


1,4 s 
(Option 001 1 I 5i 


15 ms 


MEASUREMENT TIME: 


Acquisition time - 4 - 5345A Gate Tfrrie 

- 5345A Sample Rate f 125 ms iGale 
Time -= 100 ms) 

Acquisition time - 5345A Gate Time 

- 5345A Sample Rate - 35 ms 
iGate Time *1 s,i 


Acquisition time 

> 5345A Gate Time 

■ 5345A Sample Rate 

4-35 ms 


Gate Time * t00 ms: Acquisition time 1 4 ■ Gate Time 
i 5345.A Sample Rate * 125 ms 

Gale Time.- 100 ms. Acquisition time t 5345A Gate Time 
<-5345A Sample Rate * 35 ms 


LSD DISPLAYED: 


1 Hz 




■ H.- 


534 5 A Gate Time 


5345A C 


fa 

o 


te Time 


RESOLUTION; 


2 LSD ; 1 ■ 10 1D rms ■ Freo 


■ 5 ■ LSD 


LSD ' 1-1 




ACCURACY: 

■ i minute warm up) 


r2> LSD il <■ 10 " 10 rms - Fieq 
• Time Base Error - Ftfiq 


*$ > LSD 
■ Time Base Error ■ Freo. 


Resolution - Time Base Error ■ Freq 



Specilicalions doscnbe the instrument's warranted performance. Typical at nominal performance character islics provide useful applieaiion inlormanon but are not warranted 

■LWLETT- PACKARD JOURNAL 27 



)Copr. 1949-1998 Hewlett-Packard Co. 



Pulse Mode 



FM TOLERANCE: 

(typical) 



ACQUISITION TIME: 

{typical; 



5356A.-B Input 

Auto Mode 

50 MHz p-p chirp 



S3S6A. 8 Input 
Man Mode 

SO MHz p-p chirp 



\QQ)i& 



Ext Gate Widlh i PRF 
-650 ms-(E*l. Gale ^=100 pa) 



CALIBRATION TIN 



PRF 

{Ext. Gats >100>s) 



535SA" 
0.4-1.6 GHz Input 

Instantaneous -fequency must 

not exceed 0.4-1.6 GHz 

range 

0(Freq ^00 MHz} 

5345A Gate Time 
Ext. Gate Width » PRF 
+ 45 ms (Freq ■■BOO MHz J 



5356C Input 
Auto Mode 

50 MHz p-P chirp 



5356C Input 
Man Mode 

80 MHz p-p cnirp 



Ext. G&le * . 1 00 fii 

8 (Option 001 : 7);PRF 

- 1.55 s (Option 001' 1.25 @J 

-lWMSi'(Ext Gate Widlh 

■ PRF) 

Ex( Gate >100 ^s. 

10(Optwn001-9vPRF 

-1.55 & 
(Option 001 125 s) 



S34SA Gate TFme 



i-75 ma 



Ex! Gate WirJIh X PRF 
Performed during 10 consecutive measurements, when pulse mode is se- 
lected, atier any franc panel change, or when The external gate widlh 
changes by more than 12% OnJy calibrates if external gate ia ■ 100 >as 



MEASUREMENT TIME; 

(typical) 



PULSE WIDTH 

MINIMUM 
MAXIMUM 



Acquisition Time 

- Cal'bralion Time 

-5345A Sample Hate 

5345A Gate Time or 1 00 ^st 



Exl Gale Width > 
-100 ms 



PRF 



twhichever is greater 



100 ns 
20 ms 



Acquisition Time + Calibration Time 
- 534 S A Sample Rate 

1 ji£ 

Ext. Gate Width ■ PRF 
5345A Gate Time 



Ext Gate Width ■ PRF 
-SO ms 



60 ns 
20 ms 



PULSE REPETITION FREQUENCY 

MINIMUM: 
MAXIMUM. 



50 Hz 
2 MHz 



50 Hz 
2 MHz 



Acquisition Time 

■t Calibration Time 

-1- 534 5 A Sample- Rate 

+ 100 m$ 

5345 A Gate Time or 100 M sf 

+ Ext Gate Width ■ PRF 



Twhichewer is greater 



Acquisition Ttme 

- Calibration Time 
+534SA Sample Rate 

+60 ms 

■ M ^s y Gate Time) 

Ext. Gate Width * PRF 



100 r 



100 Hz 
2 MHz 



100 ns 

20 ms 



60 ns 

20 ms 



50 Hz 

2 MHz 



MINIMUM ON: OFF RATIO: 
MAXIMUM VIDEO FEEDTHROUGH: 

MINIMUM EXT GATE WIDTH; 

f 5345 A 1 

LSD DISPLAYED' 



25 dQ typical 



15 mV p-p typical lor RF burst rise and fall times ^10 ns 
50 ns 20 ns 40 nt, 



25 dB typical 



15 mV p-p typical (or RF burst rise and la I J times =-*i0 ns 
60 ns 



RESOLUTION: 



ACCURACY: 
(after 1 minute warmup) 



5345 A Gate Time 



-2 ■ LSD t rms jitter' 



±10 x LSD 

i 5 ■• rms jitter * 



5345A Gale Time 



*2 1 LSD ± rms jitter- 
.04 

= Exl. Gate Width " 3 kHz 
■Time Base Error x Free, 



J 


1* 


> LSD 


-5 


•■ 


rms jitter" 

.05 



~ Ext Gate Width 

=24 kHz 

s Time Base Error - Freq 



±2 v: LSD ± rms jitter * 

-2 » LSD ± rms jitter * 

±Time Base Error ■ Freq ±3 kHz 

04 

" Exl Gate Width 



"rms jitter - (5345A Gate Time ■ Ex;. Gale Widlh) " - * 100 Hz 
"Specifications apply only to extern aF gating of 5345/5955. 



•ress Correction Requested 
Newlel 



HEWLE 



APRIL T9B0 Volume 31 * Number 4 

Technical Information from the Laboratories of 

Hewlett-Packard Company 

Hewlett- Packard Company, 1501 Page Mril Road 

Paid ASio. Cairfornia 94304 U.S A 

Hewlett-Packard Central Mailing Depanmem; 

Van Heuven GoedhartEaan T2i 

1 1 SO AM Amsteiueen The Netherlands 

Yokacjawa-HewFen-Packard Ltd , Suginam -Kl. 

kyo 168 Japan 

CHANGEOFADDRESS: 




Bulk Rate 
ostag€ 

Hewlett- Packarc 



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APPLIFD PHYSICS LAB 
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)Copr. 1949-1998 Hewlett-Packard Co.