TEMPORARY TECHNICAL REQUIREMENTS FOR A PULSE-SPECTRUM ANALYZER DESIGNED BY THE KOEPENICK RADIO PLANT

• Document Type: CREST
• Collection: General CIA Records
• Document Number (FOIA) /ESDN (CREST): CIA-RDP80T00246A026801770001-9
• Release Decision: RIPPUB
• Original Classification: S
• Document Page Count: 8
• Document Creation Date: December 27, 2016
• Document Release Date: January 30, 2014
• Sequence Number: 1
• Publication Date: June 10, 1962
• Content Type: REPORT

z
A 0.i 11115/1
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FORMATI,ON REPORT
INFO MATION REPORT
CENTRAL INTELLIGENCE AGENCY
This material contains information affecting the National Defense of the United States within the meaning of the Espionage Laws, Ti
18, U.S.O. Secs. 793 and 794, the transmission or revelation of which in any manner to an unauthorized person is prohibited by l.
SECRET
COUNTRY East Germany ?
SUBJECT
Temporary Technical Requirements
for a Pulse-Spectrum Analyzer Designed
by the Koepenick Radio Plant
DATE OF
INFO.
PLACE &
DATE ACQ.
THIS IS
REPORT
? DATE DISTR.
NO. PAGES 8
REFERENCES RD
JUL.1962
UNEVALUATED
INFORMATION.
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SOURCE GRADINGS ARE DEFINITIVE.
APPRAISAL OF CONTENT IS TENTATIVE
STATE
I Al ARMYf #X I NAVY I AC I
AIR
I #X I NSA
(Note: Washington distribution indicated by "X"; Field distribution by "#".)
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MATION REPORT INFORMATION REPORT
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COUNTRY
SUBJECT
DATE OF INFORMATION
PLACE ACQUIRED
S-E-C-R-E-T
REPORT
East Germany
DATE DISTR. 13. JUN 62
Temporary Technical Requirements for a NO. OF PAGES 7
Pulse-Spectrum Analyzer Designed by the
Koepenick Radio Plant
REFERENCES:
THIS IS UNEVALUATED INFORMATION
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Introduction.
At the request of the Dresden Aircraft Plant (Plant 803) in 1958* a study
was Prepared at the-Koepenick Radio Plant'(VEB Funkwerk Koepenick) on -a
OalseapeCtrum analyzer the latter was designing for Plant 803 The stud"
was-iiritten by IngWalt?Rasae, a-metber of the Keepeniok plant' Radar 50X1-HUM
DeVeiocment DecartMent
The following is a translation
I. Preliminary
PI-Ilse-Spectrum Analyzer
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Technical Requirements.
106 cps
1.1
Frequency range
10,000
range
-
1.2
Pulse duration
. 10-6 to 2106 secchda
173
Pulse sequence
500 - 3000 cps
-1.4
Intermediate-frequency input
Retterhan 1 10-3 vats rela?
sensitivity
tive to a6 pulse duration of
-
0.1 10 seconds for 50-mull-
'1 62 megacycles
meter amplitudes
175
Intermediate-frequency band width
50 103 cps
1.6
Allowable interference voltage for the
= 1 percent
(intermediate-frequency) signal
1,7
Frequency for the X-deflection (fre-
20 to 51 Cps Continually ad?
quency of the saw-tooth voltage for
the carcinotron)
justable
1.8
Allowable amplitude change with fre-
quencY Change
. 3 percent
1.9
Amplitude for the saw-toothed voltage
a) Frequency modulation of the carcinotron: 0 to 200 volts constantly
adjustable
b) X-deflection on the fluorescent screen: 1.5 x screen diameter de7
flection symmetrical to the
center of the screen
1.91 Linearity of the voltage ih 1,;9a
1.92 Pulsation factor of the voltage in
1.9a
$-E-c-R-E-T
percent
-S/!- 1 . 10-3 volts 1,1)
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II. Other Requirements.
2.1 The deflection frequency must be able to be synchronized with the re-
spective pulse frequency.
2.2 In order to produce the zero-line, the X-signal must become zero for
every 2.), 4.), 6.), etc. deflection, i.e., the intermediate-frequency
input must be short-circuited by a Switch (flip-flop).
2,3 The size of the spectrum (Maximum amplitude) 100 millimeters
2:4 Linear range of adjustment of the inter- 20 : 1
mediate-frequency dhannel
2.5 Maximum input amplitude of the intermedi- 20 millivolts
ate-frequency channel
2.6 Net voltage
2.7 Operating conditions
Pulse-Spectrum Analyzer
(Extracted from 1552)
415 V
220V - 50 cps
-30 V
Operated in the laboratory
for 8 hOurs without inter-
ruption.
1.1 A high-frequency pulse-spectrum analyzer, that automatically' resolves
a Fourier analysis, Is represented electronically. The required measur-
ing marks for the analysis of the spectrum are gated into the electronic
image. The size may be read directly from calibrated scales
1.2 Pulse-Spectrum Analyzer
1.3 In order to be able to determine the power losses that result as an
echo in radar instruments which the high-frequency pulse generator
emits, a spectrum analysis is to be made, because all the weil-known
Tech, output meters integrate, i.e., they do not give any information as to
Clbject, the distribution of the high-frequency spectrum.
The analyzer is to allow spectrums to,bg analyzed agcording to Fourier
with an impulse duration from 0,1 . 10 to 2 ;10 seconds in con-
nection with a pulse-recurrence frequency of 500 to 3000 cps.
It will be possible to investigate spectra from 1 to 100 miliiwatts.
1,4 Maximum-frequency superheterodyne receiver, the oscillator of which
will be frequency modulated over 4 range from +40 to 60 megacycles,
Methods in connection with which the frequency fluctuation can be continuously
of Solu- changed from zero up to the maximum value mentioned. The receiver,
tion therefore, scans a frequency range up to the maximum frehuency fluctu-
ation in Which the pulse Spectrum that is to be investighted is situ-
ated. The carrier frequency of the oscillator and, therewith, the
receiver may be changed over a wide range.
In'order to produce a line spectrum which corresponds to the envelop-
ing spectrumhpattern, a small frequency sector is selected'foreach
individual sweep of the pulp spectrum.
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Small intermediate-frequency selectivity-curve by converting to a
second intermediate frequency of lower nominal frequency with which
a band width from 50 kilocycles or less can be obtained. The scanned
small frequency-range is rectified and amplified and conducted to the
J-scoOd. The time axis (X-axis of the oscillograph) was modulated
synchronously with the frequency modulation of the scanning generator,
so that a steady image of the spectrum resulted.
By using :a magnetic-T in the high-frequency section of the analyzer,
a cavity frequency meter will produce a pulse bypassing through the
resonance frequency, which is conducted. to the tubes of the ?Ballo.
graph after rectification and amplifiCation of the Z-axis. In this
way, of course, a bright or dark mark is produced on the fluoreiitent
screen after the polarity is selected, which corresponds, to the posi-
tion of the instantaneous frequency that passes through. By detuning
the frequency meter, it is possible to determine the frequency by an
arbitrary point on the screen of the oscillograph.
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Subject: Preliminary Technical Requirements for a Pulse-Spectrum Analyzer
of the Institute of Electrotechnology, Main Department High-Fre-
quency
In recalculating the data presented for the projected pulse-spectrum analyzeri
it is shown that we must ask for some changes in the data in order to make the
instrument usable for our purpodet. Basically they are the dame requirements
which you too have made on the measuring instrument, 15661003e the wavelength and
the pulse width are the same as With us. In the following the individual data
in regard to the pulse-spectrum-analyzer are taken into considerationi
1. Intermediate Frequency. The value of the intermediate frequency is
not indicated in your technical Speeifiettione.r In Order to avoid overlapping
the two pulse spectra by a frequeney Of f _ ZP, the intermediate frequencied
sign --
must be expressed as
Equation lt 2 F rt VI
if the shorter impulte(slfltoebeninvettigittedAd detignated with lc.,4 provided
we take it as a basis that in the OUtOlit in 14 the secondary radii-Wean 1.4-0
percent Of the output in the primary rediati*Of the spectrum and eentributea
a small important contribution to the aMplitUde of the speCtruM0 In order to
make the Spectrum of the 0.1 midrOseeendlOng OU1Sei visible, the intermediate
frequency must, therefore, be at least 40 megtoyelea.
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3.- The Rewired Sensitivity of the Input. The sensitivity of the inter-
mediate4requeney'amplifier, which was given by you as 4:1 millivolt is not -
adequate In our opinion. If one istumes that the proportionality between in-
termediate frequency and the signal amplitude should be guaranteed, then the
following relationship should exist:
Oscillator voltage = 10 x signal voltage
or
Oscillator output . 100 x signal output.
1 For an optimum degree of mixing action from the 1 N 23 B mixing detectors
or similar cry:eels, the oscillator output must amount to 1 millivolt.
' For this reason the signal output may be a maximum or 10 microwatts. With
a degree Of mixingaction of from 10 to 25 percent (mixing damping from 10 to
6 decibel), an output of only about 1 microwatt reaches the receiver input.
With an aisumed mixing crystal resistance of 300 ohms, an interMediatefrequeney
volalp of
Equation 2: U
Zf Krist =1103OO .?17.3 millivolts,
is, therefore, in the crystal. By using a small-band intermediate-frequency
amplifier, the portion of the transmitted impulse voltage is/proportional to
, Equation 3:
- st ?
2
In which "C" .2 impulse length (a) and Li f is the band width Of the intermediate-
frequency amplifier (cps). If this factor is taken into. coirideration the 4V'
intermediate-frequency amplifier sensitivity must, therefore, amount to
:1 ..
.--67--'
. Equation 4: U_m. ng .0Zf . 17.3?10-3 .3.0110.50 10P 130 microvolts..
, i
,
In order to have a reserve, the input sensitivity must amount to about 50 micro-
volts.
The addustment of the intermediate-frequency amplifier sensitivity Should
be between 20 and 100-fold in order to be adjusted to the optimum interfereneo
interval.
-
4. Time-Base Frequency. Designing the equipment with a time-base fre.:
quency of from 20 to 51 cps is not auffieient. The 504kilooyele-wide filter of
thea intermediate-frequency amplifier must pass through a.wide frequency band..
Since each bend width has a'transient period that is characteristic only for It,
the sweep time through the frequency range must not be too great, i.e., the, Saw..
tooth time-base frequency for time defleetion and the synchronous wobbling of
the reflectors must not exceed a definite value in meegacycleSper second, do
that one of the real voltages present gives s. proportional indication -
The transient period for -i? filter is defined as
Equation 5: 't
S E-T
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and for the 50-ki1ocyc1e.4ide filter used, it therefore amounts to
Equation 6:9 1: 0.010.10-3s . 10 microseconds.
2.50.103
The duration of the filter must amount to at least 20-r for a sufficient indina.
tion (according to data by Kuepfmueller in System Theory of Electrical Communica-
tion transmission) i.e., 20T . 200 microseconds0
the range of frequencies the filter must go through differs for various pulse
lengths. The greatest area to pass through belongs to the Shortest pulse, the
spectrum of which is still to be determined. In our case, the 0..1 microsecond
long pulse amounts to about 60 megacycles, which is the extent of frequency
range required for a good analysis of the frequency spectrum.
The time required to sweep 60 megacycles must, therefore, at least amount to
6
.LIEL-linkUL ?
Equation 7: - ? - 200 microseconds . 240 milliseconds.
0.05.10 cycles
This corresponds to a deflection frequency of at least
Equation 8; . 4 kilocycles.
240?10-3
As the upper limit of the adjustable frequency for broader pulses with a narrower
spectrum, 25 cps was proposed, because this produces a flicket-free 'picture and
the spectrum can be analyzed by increasing the time-base frequency by decreasing
the number of lines in the spectrum (see also Chapter 5).'. the synchronization
of the deflection frequency with the impulse frequency is of no consequence for
the analysis of the impulse spectra in that it only causes the linei in the spec-
trum to stop.
5. Oscillator. The oscillator wobbling of +40 to 60 megacycles, which you
anticipated, should in your instrument be dealt with by a carcinotron. It would
be desirable to use one of them!becaUse then it would be possible to detune the
frequency even more. If, however, we take into consideration that a tube such
as this is not available in East Germany at the time nor in the year to come -
we were, therefore, informed as. to imports a reflex klystron adequately fills
the requirements after .scanning a range from .?30 to 45 megacycles. In an extreme
case it is necessary only to sweep 60 megacycles for the broadest spectrum, i.e.,
one 0.1 microsecond impulse with two secondary radiations at a time to the tight
and to the left of the primary radiation. A 723 A/B reflex klystron for the fre-
quency of 9375 megaoyOles is; however., manufactured in East Germany.
6. 4trlit1.0142.1p0-_. In our opinion, the flip-flop circuit which you have
provided fOr alternately opening and closing the receiver input by sweeping the
zero-line is unnecessary.
In chapter y it was calculated that the base-time frequency had to amount
to from 4 to 25 cps. A Af . 50-kilocycle-wide filter, therefore, continues
through in beat from, for example, fl . 4 Os, i.e., all 101 a 250 Osec in an
extreme case a frequency range from 60 megacyclets This means that it passes
through 240 kilocycles per Mee with an impulse sequence of 1'1 . 100008 in
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connection with impulsing, i.e., an impulsing every 1 msec still gives enough
time in which the filter that is integrated in excess of 50 kilocycles does not
receive a voltage. In
:Equation
240 kilocycles - 50 kilocycles . 0.79 . 79 percent
9:
240 kilocycles
of the time the zero line is already recorded. Lines then appear as deflections
in the vertical 1 f = 1 . 1000 . 250. In connection with higher time-base
7 T
frequencies the dead-time ratio is still more important. With a base-time fre-
quency of approximately f2 . 25 cps the frequency range of 60 Mc is swept in
1 40 msee,?i.e., the speed amounts to 1.5 MoleMsec. This means that in
1500 kilocycles - 50 kilocycles
Equation 10: . 0.972. 97 percent
1500 kilocycles
of the time the zerd:line is recorded. Deflections in the vertical then appear
as 1 . f . 1000 . 40 lines, which is already meager for analyzing an impulse
f6
spectrum. For this reason the base-time frequency must not exceed 25 cps.
7. Pre-Damping at the High-Frequency-Input. The signal energy on the
mixing crystal should not be any greater than 10 microwatts,'based on an out-
put proportional recording on the picture screen according to point 2. By tire
damping the high-frequency power in order to decrease any transmitter poWer that
is greater than 10 microwatts, a variable and a fixed calibrated Attenuation
line and a directional integrator are Provided so that a maximum of 200 ki10.:
watts transmitter output can be damped to 2 microwatts by a total of at least
110 decibels.-. 50X1-HUM
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