SYSTEM FOR TRANSMITTING VOICE FREQUENCY OUT-BAND CONTROL SIGNAL IN PCM NETWORK

摘要

PURPOSE:To transmit directly a voice frequency out-band control signal to a CPM network without using an analog receiver and an analog transmitter by utilizing the band compression and expansion technology. CONSTITUTION:A 64Kb/S digital signal of a talking channel 5 is converted into a voice band analog signal normally by a 64Kb/S D-A converter 2 and the result is transmitted to an analog signal adder 1. The 64Kb/S digital signal subject to band compression from a digital oscillator 7 as a control signal coder having a band compression function being a control signal source is converted into an analog signal at the voice frequency out-band at a 64Kb/S D-A converter 3 with band expansion function through a control signal channel 6 and the result is transmitted to the adder 1. Both the signals are added at the adder 1 and transmitted to an analog line.