'- track' subtext decoder encoder reference signal compression law for telephone type m.i.c.

摘要

The coder, for PCM telephone networks, codes analog signals arriving from a transmission path such that multiplexed digital signals are rleased onto the outgoing transmission path using a compression process. The number of incoming transmission paths is optimised at 8. A comparator compares a reference signal with the analog signal to be coded. At the beginning of each cycle the reference is disconnected to determine the sign of the analog signal and to operate a control circuit. The control circuit allows selection of one of two opposite-polarity reference signal sources.