PCM frame slip detection in a channel

摘要

In the particular embodiment of the invention described in the specification, a frame slip detector for a detecting frame slip in a 24 channel PCM transmission system using an 8 KHz frame rate supplies a 1 KHz test tone to one channel of the system. A phase shift detector detects phase shifts in the same channel and supplies them to a frame slip indicator which responds to phase shift signals within the range from 40 degrees to 50 degrees which recur at periodic intervals of at least one second and supplies corresponding indications of frame slip for each phase shift detected.