LETTER TO (SANITIZED) FROM (SANITIZED)

• Document Type: CREST
• Collection: General CIA Records
• Document Number (FOIA) /ESDN (CREST): CIA-RDP78-03424A000500010005-2
• Release Decision: RIPPUB
• Original Classification: S
• Document Page Count: 4
• Document Creation Date: December 22, 2016
• Document Release Date: April 10, 2012
• Sequence Number: 5
• Publication Date: February 4, 1957
• Content Type: LETTER

Declassified in Part - Sanitized Copy Approved for Release 2012/04/10: CIA-RDP78-03424A000500010005-2 25X1
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CONFIDENTIAL
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CONFIDENTIAL
Declassified in Part - Sanitized Copy Approved for Release 2012/04/10: CIA-RDP78-03424A000500010005-2
 Declassified in Part - Sanitized Copy Approved for Release 2012/04/10: CIA-RDP78-03424A000500010005-2
CONFIDENTIAL
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NDENTIAL
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25X1
25X1
Declassified in Part - Sanitized Copy Approved for Release 2012/04/10: CIA-RDP78-03424A000500010005-2
 Declassified in Part - Sanitized Copy Approved for Release 2012/04/10: CIA-RDP78-03424A000500010005-2
0
t
174 Hours
120 Hours
112 Hoar s
8 Hours
19 Hours
132 Hours
138 Hours
TOTAL 703 Hours
II. Trips and Conferences: None.
III. Work Done Lfuring Period:
During this report period, work has been continued in the following
areas.
1) Variable Reluctance Modulators
Now core materials, obtained from the
Subsection, have shown the feasibility of extending the operating range of
these devices to approximately 25 Mc/sec. Present work is directed towards
the location of unbalance causing an unsymmetrical modulation pattern of the
balanced modulator configuration. Such unbalanced conditions can be cancelled
for one carrier frequency by adjustment of the operating point of a driver
transistor, but this correction does not hold over a wide frequency range. With
a well balanced care, however, it should be possible to vary the carrier
frequency over a wide range without affecting the modulation pattern.
2) Mode Amplifiers
An investigation of various types of diode amplifier output stages was
conducted during the present reporting period. A "push-pall" type circuit
arranement was demonstrated to be both feasible and practical. A six stage,
direct coupled audio amplifier was constructed having an input signal level of
5 millivolts at a 20, 000 ohm impedance level with approximately 2 volts
0
Personnel:
Declassified in Part - Sanitized Copy Approved for Release 2012/04/10: CIA-RDP78-03424A000500010005-2
 Declassified in Part - Sanitized Copy Approved for Release 2012/04/10: CIA-RDP78-03424A000500010005-2
0 0
output across a ISO ohm. toad resistance. A low level A-M modulator
employing storage diodes was developed which has an advantage over
conventional diode modulators in that the storage of carriers is utilised to
produce audio power gala. The feasibility of utilising a single tranxistor
oscillator as the clock power supply was demonstrated in conjunction with
this A-M modulator circuit.
Activity in the diode amplifier field will be continued in an attempt to
develop additional circuits having practical application in radio systems.
3) Remote Tuning L"evice
(me of the major troubles experienced with these devices during
previous experimentation was what appeared to be contact bounce of the
actuating switch. A closer study of the effect shows that apparently much
of the trouble experienced is due to ringing of the quantiser core. Attempts
to eliminate this by redesigning the quantiser core and windings have been
made and the results of these changes are presently under investigation.
If these changes show the desired results, it will improve the repeatability
of irequsacy settings considerably. In that case the nest study phase will be
on the improvement of the linearity of the frequency vs. number of set
pulses characteristic.
9
4) Photo-Electronic Circuits
Measurements have been taken to explore the possibility of using fast
photo-conductors. The general results were not promising - the sensitivity
of the C was too low in all cases. The PC elements used were Lead
Sulphide "Getron" and' l ktson" cells and large area p-e photo-junctions
(solar cells). Work has been done an the development of basic logical
elements for computer circuits. This work has been directed towards
obtaining the optimum speed with the available materials. Some of these
circuits will be combined to form more complex logic sets, such as half-
adders and shift registers. If time permits, an analysis will be shade of
the symmetrical bistable stage with a view to obtaining design data necessary
for obtaining maxiinuxn speed of operation.
0 IV. Plans for Next Month.
During the said report period, work will be continued as indicated in the
foregoing paragraphs. In addition, the present series of measurement being
made on "Magnistors" used as electrical tuning elements will be continued.
Their frequency stability as a function of temperature is being determined.
Two approaches have recently bean taken :n the magneto-resistive field. One
has been towards the development of a contact plating technique for slabs of
Declassified in Part - Sanitized Copy Approved for Release 2012/04/10: CIA-RDP78-03424A000500010005-2