TEXT OF LETTER RE OSCILLOSCOPIC DEVICES WITH ATTACHED ROUTING SHEET

• Document Type: SPECIALCOLLECTION
• Collection: General CIA Records
• Document Number (FOIA) /ESDN (CREST): 00184359
• Release Decision: RIPPUB
• Original Classification: U
• Document Page Count: 2
• Document Creation Date: January 21, 2025
• Document Release Date: January 15, 1983
• Publication Date: May 10, 1951

UNCLASSIFIED RESTRICrED CONFIDENTIAL
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CENTRAL INTELLIGENCE AGENCY
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APPROVAL INFORMATION SIGNATURE
ACTION DIRECT REPLY ,RETURN
COMMENT PREPARATION OFREPLY DISPATCH
CONCURRENCE RECOMMENDATION FILE
, .RKS: This is a text of a letter received
Would you please
uc th s bac. with an ndication as to whether
or not there appears to be an Agency application:
either domestically or overseas.
SECRET CONFIDENTIAL RESTRICTED /UNCLASSIFIED
FORM NO.
30.4
SP 1947
We have some electronic equipment which we believe may be of interest
to you. It is made up of four separate units. The first unit is a tape
recorder of extremely high fidelity capable of reproducing in intimate
detail all the inflections, nuances, and tones encountered in human speech.
The recording can then be played back through the second unit, a specially
designed oscilloscopic device which flashes on a screen in the most exact
detail a moving picture of these inflections and tonal qualities.
The third unit may be employed to halve the speed of the recording
and, in turn, to double the resultant sound frequency thus providing a
geometrically perfect picture of a spoken word with this picture moving
at a rate slow enough to permit careful visual examination.
A fourth unit permits the transfer of these oscilloscopic curves to
a permanent paper record for static visual analysis and comparison.
This equipment group can be used in making almost micrometric analyses
of the speech characteristics peculiar to a particular locale. Direct com-
parisons can be made of the speech habits of individuals known to come from
a particular place with those of another person allegedly from the same
place but who may be suspect.
This same equipment may be used for polishing away speech habits
which might result in the detection of an operative.
We would appreciate an opportunity to discuss this matter with you in
greater detail at your convenience.