PROPOSAL NO. 57-649E MINIATURIZED DATA RECORDER WITH PLAYBACK UNIT

• Document Type: CREST
• Collection: General CIA Records
• Document Number (FOIA) /ESDN (CREST): CIA-RDP78-03424A001400060026-4
• Release Decision: RIPPUB
• Original Classification: K
• Document Page Count: 15
• Document Creation Date: December 27, 2016
• Document Release Date: September 11, 2012
• Sequence Number: 26
• Publication Date: April 23, 1957
• Content Type: REPORT

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Proposal No. 57-61~9E
MINIATURI~ID _DATAnRE~
V~TH PLAYBACK UNIT
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Proposal Tdo. 5?-61~9~
STAT
MTNIATURI'~ED DPtTA~ RECORDF.~t
WITH PLAYBACK UNIT
Technical Program
S~ibmitted by
STAT
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I INTRODUCTION
This proposal has been prepared at the request of
for submission to the U, Sa Governments The program outlined
herein covers the electrical engineering aspects of development of a minia~
turized data recorder and a playback units The development program described
is based on the Specification provided, Noe 57-A-10~9m1~, and on discussions,
between representatives of
II RDaUIREMENTS
The detailed requirements are given in the Specification and will
not be repeated heree The primary requirement is for a highly miniaturized
three-channel tape recorder for voice and pulse data recordings Ttivo channels
are to be used for data recording while the third is for voice and reference
frequency recordings 'Provisions for monitoring the signal being recorded are
requirede The recorder must be capable of recording only; a separate non-
miniaturized playback unit is to be provided for rewind and data playback.
Primary features of the recorder, in order of priority, are as
le Size
The complete recorder, including tape, electronic circuits,
drive mechanism, and power source, shall be contained in a volume
5" x 3" x 1 1/2" < .
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2. Frequency Response
The overall response of the system shall be constant within
plus or minus 3 db from 250-cps to l0 kc. It is also desired that
pulses of 5 microseconds or longer duration be recorded `and repro-
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duced as faithfully as,possible.
3. Record Time
The recorder should provide a total recording time of 60
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minutes on one reel of tape.
It is apparent thatlthese requirements are not mutually compatible
and. compromises will undoubtedly. have to be made. Another difficult require
ment in view of space limitations is that of providing`a 1000,cps reference
signal stable to 1 part in 50,000 over the operating temperature range of
minus 30?C to plus 50?C, The remaining operational, environmental, and
constructional requirements are achievable from an electrical standpoint and
will not be discussed in this proposal. .Anticipated problems related to the
requirements given above are discussed further in Section III.
III DISCUSSION OF THE PROBLIl~I
The basic problem is that of recording a maximum amount of infor-
it is inferred that detailed) information about pulse shape, rise time, width,
amplitude, and repetition rate would be desirable, To preserve this inf or-
mation for a 5 microsecond pulse a record and playback system having an upper
frequency response of 200 kc to 2 Mc would be required. Considering the
200 kc response as minimum,and assuming a realizable wavelength for tape
mation in a minimum space. Thus, the nature of the information required
becomes of prime importance.) The Specification states- that 5 microsecond
pulses shall be recorded and reproduced "as faithfully as possible". Thus,
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recording, a tape speed near 100 inches per second would result. For 60 min-
utes recording on tape using 1 mil Mylar backing this, would require 30,000
feet of tape occupying a volume of 135 cubic inches. Since this is many times
the total allowable volume for the entire recorder, it is obvious that less
detailed information can be presented.
An absolute minimum amount of information is that of realizing
when pulses have been recorded. If this is refined slightly to recognition
of a single pulse, two distinct pieces of information can be obtained;
1) the presence of the pulse, and 2) the repetition rate. In addition, it
may be determined if the pulse source is interrupted (either at the source or
due to scanning). T~arge variations in repetition rate would also be recognizeda
Detailed information such as pulse shape, width, and rise time would be lost.
Depending on mode and level of recording, some information relative to pulse
amplitude (including amplitude modulation) would be obtained. Thus, a reason-
able goal appears. to be that of recognizing the presence of a single pulse..
~!lith this in mind, it is now reasonable to consider a more restricted
record-playback system. Vdhen a short-duration pulse is applied to a record
head such that the tape moves only a small fraction of the head gap-width
during the pulse time, a segment of tape is recorded the length of which is
essentially equal to the head gap-widths In order to record the next pulse
the tape mast be moved sufficiently to separate the two pulses on the tape
(2 gap widths). Under these conditions, the minimwn allowable tape speed
becomes a function only of the maximum repetition rate being recorded. Each
pulse causes a segment to be recorded so long as the, repetition rate does not
become so high that insufficient 'space is left between the recorded segmentse
Essentially, the recording process (in particular, the head gap) performs a
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pulse--stretching function since the recorded pulse length is primarily a
function of gap-width rather than primarily.a function of pulse times On
playback (same tape speed as record) the recorded pulse-will affect the play-
back head much longer than it took to record the pulsed Thus, the information
obtainable from the record will be concentrated more in the lower frequency
spectrums The minimum information of detecting whether a pulse has been
recorded and determining repetition rate is available from the fundamental
component of the recorded patterns
In the way of example9 a practical system might bee
Maximum repetition rate = 8000 cps (125 microsecond period)
Effective head gap = Os00025 inches
H
Tape speed = (8000) (,0005) = 1~,0 inches/sec
The required tape volume for this system is 60?~ cubic inches compared to 135
cubic inches for the system providing the more detailed informations More
important, it represents only 1200 feet of tape which can be accommodated in
a reel of practical dimensionso Since tape is not adaptable to varied packing
configurations the length of tape is usually of more concern than volumes
It is presumed that the agency requesting this development program
expects the less detailed information9 since the upper frequency response of
l0 kc specified is compatible with the minimum information obtainable from a
system such as .that described abovee
The discussion. and example given above indicates the factors
important in the design of the recorders The recording process should be
relatively broad band so that a short duration current pulse is applied to
the heads This will cause the recorded segment to be as short as the head
gap will allow, rather than being spread out due to inadequate frequency
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response of the record amplifiers The amount of pulse stretching will then
be only a function of the head gapo In addition, this will make the recorded
amplitude more independent of pulse width and allow interpretation of the
signal to derive pulse amplitude and amplitude modulation information9
Reduction of the effective head gap to an absolute minimum is the only way
to increase the pulse density on the tepee There are other important consider-
ations in the design of the h~ade Among these are that the pole tips should
not saturate on pulse peak) (this would cause spreading of the recorded pulse)e
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Also, to obtain sharp recording the head must be designed for a high self?
resonant frequency and of an impedance level such that aconstant-current
drive is, practical e
It should be noted that with high pulse density recording such as
proposed here (2000 pulses per inch or higher) pulses will be lost occasionm
a11ya This"drop-out" phenomenon is particularly important in digital computer
applicationso However9 it is assumed that in the application of the miniature
recorder an occasional missing pulse will not have the serious consequences it
has in computer applicationso
2n addition to min3.mizing the required volume of tape by using
maximum possible ,pulse density, consideration should be given to decreasing
space required by tape take~upd In comrentional systems an empty space equal
to tape volume must be allowedo This could. be reduced by utilizing for take-
up the space vacated by the tape as it is recordede Another technique might
consist of rotating the reel, of tape without unwinding and have the head
essentially thread through-the wound reel of tepee Thus, no winding and
unwinding occurs and no take~up space is requirede Special head designs may
be possible which would facilitate mechanical designs of this types
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Space taken by the batteries can be conserved by designing the
circuits for minimum power dra3ne At the higher temperatures germanium
transistors may draw several times the current required for normal operations
Silicon transistors should be considered from this standpoint (the temperas
tyres required are not excessive for germanium transistors)o However, silicon
transistors do not operate satisfactorily,at as low voltages as germanium, and
the power required may actually be higher than that for germaniumo This matter
will be resolved in the early stages of the programs
Another design consideration for space conservation9 from the stand-
point of number of components required as well as power, is that of type of
recording bias to be used e' For pulse recording, bias is .not essential; how-
. ever, voice recording requires either amc or d-c biase The 15% allowable
distortion permits the use of d~c biase Use of d=c bias would eliminate the
bias oscillator circuit, but both voice and pulse recordings would require
higher head drive than that required using a=c biase Again, the choice must
be made?on the basis of overall space conservationo
The requirement for the stable 1000 cps oscillator is beyond that
considered practical using conventional componentsd However; previous work
miniature low-frequency control element which offers great advantages in an
by
application such as this It is anticipated that wi11 supply this
element designed for 1000 cps operation for use in-thee recorders
The design of the playback unit presents no major difficultiese
It is believed that the most efficient and economical approach is to use a
commercial transport unit, modified to provide such requirements as variable
speed drives The playback electronics will be specifically designed accord?
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ing to the requirements of the Specification.
N THE RES~CH PROGRAM
Ao Sco e ,
The work to be carried out by
the electrical engineering aspects of the development program, Specifz.cally,
this includes. analysis of thelelectrical requirements and determination of
the electrical charaeteristics9 design and construction of the complete play-
back unit9 development of the recorder circuits9 head design and construction,
.and consulting services to relative to magnetic recordingo
An engineering mode]. of the playback unit will be deliveredo
Developmental circuits and heads for the recorder will be delivered to
i
These circuits will be suitables by design and choice of components, for
inclusion in the engineering model of the recorders However9 the final
fabrication of the electronic',s included in this unit will be performed by
Throughout the program close liaison will be maintained between
to insure compatibility
of the mechanical and electrical componentse Devious joint efforts between
the two organizations have shown that this close coordination is practical
and yields excellent resultsd
The frequency control element for the 1000 cps recorder oscillator
will be supplied by
personnelo
for incorporation into the circuits designed. by
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In view of the stringent requirements set forth and the problems
they present, the Specification is considered to be a goal rather than an
absolute requirements It is believed that the proposed program will result
in a highly miniaturized recorder basically meeting the objectives of the
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procurement, but no guarantee can be given for meeting each specific require-
ment.given in the Specification.
B. Administration ~
The work outlined in this proposal will be performed on a governs
meet sub-contract from
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will be perf ormed by personnel of Electrical Engineering STAT
Research Department. Close working relationships between and STAT
personnel will be maintained to insure unity of direction. STAT
Bi-monthly progress.~reports will be submitted in addition to minutes
of each meeting between the two organizations. A final report will be submit-
ted summarizing the development work and describing in detail the equipment
developed. This will include; all necessary schematics, drawings, and com-
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ponent specifications.
Pertinent experience of land specific background of
personnel likely to participate in the proposed program are given in the
following section. Time and 'cost estimates are given in Part II of the
proposal.
V BACKGROUND AND E%PEftIENCE
has been active in magnetic recording work for many
years, both in basic research and in extending the practical applications.
Staff members are continuously engaged in magnetic recording work under
government, and industrial sponsorship. The scope of work varies
from design of special headsito development of complete data recording and
processing systems. Recent. work has included design and application of the
magnetostatic playback heads The output of the head is proportional to flux
rather than rate-of-change of flux. Thus, magnetic records can be read at
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reduced-speed playback9 including zero9 without loss of amplitude or fidelity.
Staff members have had.wide experience in transistor circuit design
problems. This experience includes d-c amplifiers, pulse circuits, low-noise
amplifiers, control circuits, and many special applications. One specific
program was a detailed-study of transistor circuits for magnetic recording.
Circuits were designed and tested for each record and playback function.
Included in the study were record amplifiers bias and erase oscillators, and
playback amplifiers. Consideration was given to head impedance requirements,
compensation9 and other factors important in obtaining quality reproduction.
The following people are likely to contribute to the proposed
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VI SUMNl~RY
A program covering the ,electrical engineering aspects of the
development of a miniaturized data recorder with associated playback unit
is oatlined in this proposal. Many problems must be overcome in order to
meet the objectives set forth. It is believed that the combined knoti~~ledge
and experience of
personnel represents excellent background for effective pursuance of the
proposed program.
Respectfully submitted,
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Proposal Noa 57-6t~9E
STAT
I~'IINI~TURI~ED DAT~i REC?RDfft
.Time and Cost Estimate
Submitted by
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It is estimated that the proposed work can be completed within
10 months of initiation of work. .The breakdown of estimated cost is as
follows z
Salaries
Engineers (13 man months at $700/mo avg.) $ 9100
Technicians (6 man months at $50~/mo avg.) 3,000
Shop labor (180 hours at ~3.25/hr avg.) 585
Draftsmen (160 hours at ~2.75/hr avg. ) !~l~0
Total Salaries X13 j1?5
Overhead at actual cost, estimated. at 86~ of salaries 11,287
Purchased materials and components., 1,,700
Travel and Communications 150
Reproduction of Reports, Drawings, and Schematics 100
Total .Cost
Respectfully submitted,
1,581
X279 9~3.
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