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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
FHULT
XX^24pI*-PAnEUS
O0»
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
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