Recorder did not possess erase head nor was it capable of automatically rewinding reel of tape for reuse. Test results show that FM carrier recording signal with sufficient intensity will by itself erase previously recorded data as new data are being recorded. Automatic rewinding was accomplished by adding conventional metal leaders and appropriate circuitry

Asadourian, A. S.

Perz, D. A.

English

NASA Technical Reports Server

November 1973	 B73.10195 
S NASA TECH BRIEF 
Lewis Research Center	 4r 
NASA Tech Briefs announce new technology derived from the U.S. space program. They are issued to encourage 
commercial application. Tech Briefs are available on a subscription basis from the National Technical Information 
Service, Springfield, Virginia 22151. Requests for individual copies or questions relating to the Tech Brief program may 
be directed to the Technology Utilization Office, NASA, Code KT, Washington, D.C. 20546. 
Automated Operation of an

Instrumentation FM Tape Recorder 
.
It was necessary to totally automate an instrumenta-
tion FM tape recorder used for the continuous recording 
of failure data in an endurance test facility. The previous 
procedure was to record the data at 38.1 cm/sec (15 
in/sec) and then, every 96 minutes, manually remove the 
recorded tape and replace it with a degaussed roll. The 
recorded tape representing history of a failure was stored 
for several hours and then degaussed prior to being used 
again. 
Total automation presented several problems. The 
particular instrumentation recorder in use did not possess 
an erase head no was it capable of automatically 
rewinding a reel of tape for reuse when the end of the 
tape was reached. Tests were conducted to evaluate the 
not very well known or published fact that an FM carrier 
recording signal with sufficient intensity will by itself 
erase previously recorded data as new data are being 
recorded. The results showed that, with this method, new 
data could be rewritten over old data, without noticeable 
recorded signal deterioration or excessive noise, until tape 
wear occurred. Typically, the tape was replaced after 25 
cycles. 
To utilize this method of automatic FM erasure 
effectively, to still maintain an adequate history of data 
on the tape, and to reduce the ratio of rewind time to 
record time, it was desirable to slow the recording speed. 
The manufacturer's manual suggested using a recording 
speed of 38.1 cm/sec (15 in/sec) to give the required 
frequency response. But it was found that with the same 
electronics and FM center frequency, the recording speed 
could be reduced by 50% to 19.05 cm/sec (7.5 in/sec) 
without noticeable recorded signal deterioration. The 
result was an increase in total recording time from 1.6 to 
3.2 hours while the rewind time remained the same 
(approximately 3 minutes).
Automatic rewinding was readily accomplished by 
adding conventional metal leaders and appropriate cir-
cuitry. Shortly after a failure occurs, a computer stops the 
tape recorder to maintain intact approximately three 
hours of history. 
This modified FM tape recorder has been used con-
tinuously to automatically record failure data for over 
10,000 hours without any problems. 
Note: 
No additional documentation is available. Specific 
questions, however, should be directed to: 
Technology Utilization Officer 
Lewis Research Center 
21000 Brookpark Road 
Cleveland, Ohio 44135 
Reference: B73-10195 
Patent Status: 
NASA has decided not to apply for a patent. 
Source: A.S. Asadourian and D.A. Perz
Lewis Research Center 
(LEW-1194 1) 
. Category 02 
This document was prepared under the sponsorship of the National
	 Government assumes any liability resulting from the use of the 
Aeronautics and Space Administration. Neither the United States
	 information contained in this document, or warrants that such use 
Government nor any person acting on behalf of the United States
	 will be free from privately owned rights.
https://ntrs.nasa.gov/search.jsp?R=19730000195 2020-03-17T07:09:14+00:00Z
. 
fl


Automated operation of an instrumentation FM tape recorder

Abstract

Similar works

Full text

Available Versions

NASA Technical Reports Server