Digitizer accomplishes both N bit pulse code modulation /PCM/ and delta modulation, and provides modulation indicating variable signal gain and variable sidetone. Other features include - low package count, variable clock rate to optimize bandwidth, and easily expanded PCM output

Monford, L. G., Jr.

English

NASA Technical Reports Server

August 1971	 Brief 7 1-103 18 
NASA TECH BRIEF 
Manned Spacecraft 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. 
Multifunction Audio Digitizer for Communications Systems 
An audio digitizer that accomplishes both "N" bit 
PCM and delta modu1ation .has been developed for use in 
advanced communication systems. It was designed speci-
fically for audio application and provides modulation 
indicating variable signal gain, and variable sidetone. 
The digitizer has no frequency-dependent param-
eters or components and consists of an active device 
count of four dual-in-line packages for the minimum 
standards and resolution of four bit PCM. The system 
can easily be increased to eight bits PCM by the addition 
of another four bit counter and a different D to A con-
vertor.
Other features of the digitizer include: a lower 
package count than most PCM or delta modulation 
systems; a clock rate that may be varied to optimize 
bandwidth, and a PCM output that can easily be ex-
panded without major circuit modification. 
This circuit is applicable as a building block for 
advanced communications systems. It represents a sim-
plified audio modulation technique and should be of 
interest to manufacturers of data communication equip-
ment.
Note:
Requests for further information may be directed 
to:
The Technology Utilization Officer 
Manned Spacecraft Center, Code JM7 
Houston, Texas 77058 
Reference: TSP71-103 18 
Patent status: 
This invention is owned by NASA, and a patent 
application has been filed. Royalty-free, nonexclusive 
licenses for its commercial use will be granted by NASA. 
Inquiries concerning license rights should be made to: 
The Patent Counsel 
Code AM 
NASA Manned Spacecraft Center 
Houston, Texas 77058 
Source: Leo G. Monford, Jr.

Manned Spacecraft Center

(MSC-1 3855)
 
Category 02 
This documett was prepared under the sponsorship of the National 
Aeronautics and Space Administration. Neither the United States 
Government nor any person acting on behalf of the United States
Government assumes any liability resulting from the use of the 
information contained in this document, or warrants that such use 
will be free from privately owned rights.
https://ntrs.nasa.gov/search.jsp?R=19710000316 2020-03-17T02:21:23+00:00Z


Multifunction audio digitizer for communications systems

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