VISIT TO THE NATIONAL BUREAU OF STANDARDS

• Document Type: CREST
• Collection: General CIA Records
• Document Number (FOIA) /ESDN (CREST): CIA-RDP78-03172A000300050018-6
• Release Decision: RIPPUB
• Original Classification: S
• Document Page Count: 2
• Document Creation Date: December 22, 2016
• Document Release Date: April 9, 2012
• Sequence Number: 18
• Publication Date: January 19, 1956
• Content Type: MEMO

Declassified in Part - Sanitized Copy Approved for Release 2012/04/10: CIA-RDP78-03172A000300050018-6
.19 January 1956
SUBJECT : Visit to the National Bureau of Standards
1. Time and Place of Meeti : The meetings were held at the
National Bureau of $ , 137 nuary 1956.
2. Attendance: Mr. Koidan Sound Section NBS
Mr. Wildhack Sound Section M3S
Mr. Stern Sound Section NBS
APD
3. Purpose of Meeting:
b. Discuss the progress of the ultra sonic measurement
program at NBS
4. Discussion:
a. Mechanical Demodulator: The mechanical demodulator
device was discussed with Mr. Koidan. He stated that the
Sound Section had obtained a copy of R. K. Potter's patent
on this device and was quite intrigued by it. Various members
of the section put forth their comments on this device with
the conclusion that it was feasible and should, if we so
desired, be tried. The only difficult part is, of course, the
audio demodulator. NBS ran some crude preliminary tests using
a 30 KC signal, a hollow core of barium titanite, and a table
top to make the core non linear. A 400 cycle hum could be heard
by the human ear from this setup.
FIBS will now make some small crude demodulators, using
their available plastic films. FIBS was informed that if they
so desired, a work order could be arranged through
for the development of this device. They felt that at present
they would prefer to charge the expense to the allotment they
are using on the microphone evaluations and if further
experiments prove fruitful, a new work order could be s6t up.
The undersigned feels that this patent is a challenge to the
Sound Section and that their interest in it is to our benefit.
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Declassified in Part - Sanitized Copy Approved for Release 2012/04/10: CIA-RDP78-03172A000300050018-6
 Declassified in Part - Sanitized Copy Approved for Release 2012/04/10: CIA-RDP78-03172A000300050018-6
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NBS has a few microphones left to evaluate, namely the
ones supplied by ASD. NBS needs certain specifications on these
microphones before further work can be done on then. The infor-
mation needed is the type of microphone, the impedance, and the
voltage of these microphones, since they are encased in sealed
brass cases or in hearing aid cases. Someone from ASD will be
asked to accompany the undersigned on the next visit to NBB.
b. P s of the ultra sonic measurement at
ABS: Mr. Wild k reported on the progress NBS has made to
fie. Work is continuing on ultra sonic measurements of walls.
Wall correlation studies are still in progress and results
so far show that posts, pillars, etc, can be picked out in
walls. However, determining the thickness of walls is
another utter and so far results have been unsatisfactory.
Preliminary microwave tests have been run and the results
are not encourging. Tests have been made on cement blocks
with either no signal pickup or the correlation for the block
has been very poor. Work is continuing on this approach.
The results of US's work on ultra sonic measurement and
microwave measurement can be summed up by saying that at
present, neither of the two approaches appear to be satisfactory
or encouraging.
c. The undersigned has been invited to the "Open House"
being held by the Office of Basic Instrumentation and O at
the Bureau of Standards an 26 January 1956. If satisfactory
arrangements can be made, the undersigned would like to attend
the function.
5. Actions:
APD - Supply HBS with information on the microphones supplied
to them by ASD.
Tffi APD
Distribution:
1 - NBS Mike File
1 - Ad Hoc #25
1 -AWS
1 - Chrono
AWS/lj
Declassified in Part - Sanitized Copy Approved for Release 2012/04/10: CIA-RDP78-03172A000300050018-6