Digroup Data Reduction System.
J. B. O'Neal, Jr. . · 1978
This report describes the design and construction of a Digroup Data Reduction (DDR) system. The DDR system compresses the bit rate of two TI PCM telephone speech carrier systems down into a 1.544 mb/sec bit stream normally occupied by one T1 carrier system. The DDR system uses a combination of Differential PCM (DPCM) and Time Assignment Speech Interpolation (TASI) to accomplish this 2:1 compression task. The report contains design details of the prototype model. The prototype was constructed using standard TTL logic. (Author)