FREQUENCY SHIFTED MODULATED CARRIER PROTECTIVE RELAYING SYSTEM WITH AMPLITUDE MODULATED VOICE COMMUNICATION

摘要

Relaying apparatus using a carrier wave which shifts frequency to perform its relaying function and which carrier wave is amplitude modulated, at frequencies greater than the shift frequency of the wave, to provide a voice channel which has no effect on the relaying operation; the lower frequency magnitudes of the voice frequencies being attenuated so that the amplitude modulation of the wave is solely at frequencies higher than the shift frequency of the frequency modulated wave; the ringing frequency being selected to be above the magnitude of the shift in frequency and below the attenuated voice frequencies.