RINGER SIGNAL MODULATION AND DEMODULATION SYSTEM

PURPOSE:To transmit information with high quality by applying phase modulation to a binary signal of a ringer signal into a frequency having 2-mode phase, sending the result, demodulating the reception signal subjected to phase modulation into the binary signal to attain a band over a conventional talking pass band in a private talking band per limited talking. CONSTITUTION:The binary ringer signal fed to an input terminal 1 is subjected to phase modulation into a frequency having 2-mode phase by a phase modulation circuit 7 and the phase modulation signal is subjected to frequency multiplex with other channel for the talking band of own channel by a carrier multiplex section 3 and the result is sent to a terminal 4. The signal inputted to the terminal 4 is separated into the talking band and the ringer signal at each channel by the carrier multiplex section 3 and the phase modulation frequency having a phase of the 2-mode to be separated is demodulated by a phase demodulation circuit 8 to be converted into a binary signal of ground/open and the result is sent from the terminal 6. The ringer signal frequency f3 subjected to phase modulation is possible for information sending of binary ringer signal by one frequency only and the talking band f0 is made remarkably wider than a conventional band.