RD 54 TASK 5 PHASE I PROGRESS REPORT #1 - MODEL C

• Document Type: CREST
• Collection: General CIA Records
• Document Number (FOIA) /ESDN (CREST): CIA-RDP78-03300A001600010026-4
• Release Decision: RIPPUB
• Original Classification: S
• Document Page Count: 7
• Document Creation Date: December 22, 2016
• Document Release Date: December 28, 2011
• Sequence Number: 26
• Content Type: REPORT

Declassified in Part - Sanitized Copy Approved for Release 2011/12/28: CIA-RDP78-03300A001600010026-4
RD 54
TASK 5
PHASE I
FI DENTIAL
PROGRESS REPORT #1 - MODEL C
3 copies to:
1 copy to:
1 copy to:
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5 COPIES DISTRIBUTED AS FOLLOWS:
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RD 54
TASK 5
PHASE I
PROGRESS REPORT #1 - MODEL C
30 DECEMBER 1955
OBJECTIVE:
To study and evaluate factors and components involved in the design
of a miniature infrared voice communicator. To plan and schedule the
complete task 5 for the production of Model C equipment.
DATA:
General Planning.
A schedule has been prepared to outline the overall planning of
the project. The dates are approximate, of course, but represent
the target dates at this time. The principal schedule dates are given
below.
Study phase 21 November 1955 to about
23 January 1956
Study phase conference During week of 23 January 1956
Preliminary design 23 January 1956 to 1 March 1956
Design and construct 1 March 1956 to 1 June 1956
two design approval
models
Customer evaluation 1 June 1956 to 15 June 1956
Design conference 15 June 1956
Development changes 15 June 1956 to 1 October 1956
and construct 4 models
Deliver 20 copies of 1 October 1956
Operating Instructions
Finish technical man- 21 November 1956
ual, final report, and
manufacturing drawings
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Specifications.
Several tentative specifications have been set up on the basis of
the proposal and previous discussions with customer'personnel.
These are subject to change as the study and later phases progress.
1. Range:
Average clear weather night range is to be in excess of one
land mile when used with a Model B equipment. Range is to be
greater than 1/4 land mile when used with another Model C unit.
The daylight range of the equipment is to be as close to the
night range as possible and preferably will at least meet the
above minimum range requirements. The range is to be made
as great as practicable within the size requirements of the
equipment.
2. Case Size:
A maximum case size of 6 inches long by 12 inches perimeter
has been set. A probable shape will give dimensions 1-1/2" x
4-1/2" x 6". No weight specification has been set. Lightweight
materials will be used where possible and the small case size
will prevent excessive weight.
3. Batte rie s
A life of one to two hours at 70?F in transmit condition is
required. Batteries may be dry cells of various types such as
mercury cells, etc., or miniature storage cells.
4. Temperature Conditions:
The equipment shall be capable of storage at temperatures
from -65?F to +160?F. Efforts will be made to provide for ?
reasonable operation over an ambient temperature range of 15 F
to 120? F. It is known that optimum operation will not be attain-
able over this range. The main problems will be reduced battery
output at low temperatures, change in galvanometer modulator
damping with temperature, and variations in transistor parameters.
5. Vibration Tests:
The equipment shall withstand vibration testing from 5 to
55 cps at .060" total excursion for 1/2 hour in each of three
principal planes.
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6. Additional Requirements:
Where applicable and reasonable the requirements of speci-
fication MIL-E-16400(SHIPS) dated 1 May 1953 will be followed.
This applies especially to materials and finishes.
Technical Study.
1. General equipment characteristics:
In order to obtain empirical data on several operational
characteristics of the proposed communicator, a breadboard
optical unit is being made. Most of the parts for this have been
completed, and it is expected that it will be ready for testing by
January 10. With this unit it is proposed to evaluate simultaneous
operation of receiver and transmitter as an aid in "find" and
alignment procedures. Push-to-talk control of the lamp will
be tested and general requirements as to operating controls will
be checked.
The breadboard optical unit will be used in conjunction with
an amplifier unit which has been assembled. The amplifiers,
employing vacuum tubes, are for use only with the breadboard.
Transistor amplifiers will be designed and developed later. In
the optical breadboard no attempt has been made to miniaturize
the layout. Rather, it is considered more important that it be
versatile and readily adaptable to modification.
2. Optical system:
The breadboard will use 1-1/2" diameter, 1-1/2" focal
length lens systems similar to those of Model D for the objectives.
Separate systems will be used for receiver and transmitter. The
1-1/2" aperture lenses will be used for test purposes because of
their availability. However, they will be stopped down with a
mask to produce a 1" square aperture. The performance of the
breadboard with these optics and various cells and lamps will
be checked in operation with a Model B equipment. One of the
Model B equipments that went through environmental testing is
being repaired and will be used in this testing program.
The use of small optics with correspondingly short focal
lengths will allow the use of a very small lamp. It appears that
a focal length between 1 and 1-1/4 inches can be used. Several
sample lamps of about 3/4 watt size and satisfactory brightness
have been obtained with filament coil dimensions of about 0.016"
x 0.040". Such a lamp used with a 1-1/8" focal. length objective
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would produce a .8 x 2.0 degree beam. It is believed that such a
beam will be satisfactory for a non hand-held unit. This can be
better evaluated with the use of the breadboard unit.
Two Mallory Type RM-12R mercury cells were tested in
operation of a sample lamp. Two hours continuous operation
were obtained the first day, about 1-2/3 hours the seco8d, and
one hour the third day. The tests were conducted at 75 F. In
more realistic, intermittent, operation even longer battery life
can be expected. Further tests will be conducted to determine
more completely the battery life under various temperature and
duty cycle conditions.
Midwestern Instruments has been contacted regarding a
smaller galvanometer for use as a modulator. The size of the
modulator used in the Model B equipment together with the
relatively large magnet and pole piece required prevent its use
in this design. In addition the audio power required to drive a
mirror assembly that is larger than necessary would needlessly
complicate output amplifier design requirements. It was thought
that Midwestern's smaller Model 102 galvanometer could be
suitably modified for this application and, accordingly,
tentative specifications were submitted.
To accommodate the larger window that would be required
Midwestern recommended a unit in which the suspension system
and lower part of the barrel are similar to their Model 102
while the window and upper section of the barrel are similar to
that supplied to us for the Model B equipment. This would
allow use of the large window without weakening the barrels as
would otherwise result if the regular Model 102 barrel were
modified. The new galvanometer would be about 2-5/1611 long
or little more than three quarters the length of the one used in
Model B. The new magnet structure required will be corres-
pondingly smaller than that of Model B. The galvanometer
current sensitivity is estimated to be approximately 2. 5 times
better than the old one because of the smaller moving structure;
the mirror size would be .020" x .090".
3. Amplifiers:
Transistor amplifiers are being studied and several bread-
boards have been built. Present information on the galvanometer
modulator indicates that about 75 to 90 mw of audio power will
be required for 100% modulation. A push-pull class B output
stage (common emitter) with single class A driver has been
built which delivers about 90 mw output. A quiescent current
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of about 3 ma and a maximum signal current of 28 ma are required
from a 6V battery.
It appears that a single stage ahead of the driver can be used
either as the microphone preamplifier or the tone oscillator. A
parallel "T" rejection filter applied in a negative feedback path
around the preamplifier will give the necessary rising high
frequency response for maximum speech intelligibility.
Some study of the receiver amplifier has been made. It seems
quite certain that with the receiver low-noise transistors now
available the first stage as well as the others can employ
transistors. It will be necessary to transformer couple the cell
to the first stage for efficient power transfer. Tests indicate
that a. four stage RC coupled transistor amplifier will give the
necessary performance for the receiver. A noise of less than
10 microvolts referred to the input has been achieved. Power
requirements were about 2. 5 volts at 3 ma.
PROGRAM FOR NEXT INTERNAL:
The optical breadboard unit will be assembled and tests will be made
with the vacuum range optical attenuator to determine the effectiveness
of the one inch square optics. Initially 'a 1 x 1 mm Kodak Ektron lead
sulfide cell will be used and a lamp requiring about 3/4 watt will be em-
ployed. Range determinations will be made of the breadboard unit operating
against a Model B equipment. Further tests will be made to evaluate the
performance of simultaneous receiver and transmitter operation in the
"find" procedure.
Based on the information gained in this study and planning phase,
more definite specifications will be set regarding the components and
characteristics to be incorporated in the design approval models. Toward
this end a study phase conference will be held with customer technical
representatives. This conference is tentatively scheduled for some time
in the week of 23 January 1956.
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IUFI ENIAL'
Report prepared by:
Report approved by
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