Differential companding PCM (DC-PCM) by removed bit accumulation

By modifying a near instantaneous companding transmission system, a method that is capable of transmitting differential PCM for satellite sound broadcasts, is found. The modification requires only an accumulator added to the present sending side. Difficulties in transmission or signal restoration which result from bit removal during compression are solved by a so called removed bit accumulation method. The principle of the system is explained, and its features and performance based on the results of computer simulation and of measurements made on an experimental equipment, are described. Comprehensive subjective tests are performed and it is shown that high-quality sound transmission is achieved even by an 8-bit transmission channel.