TECHNIQUE FOR SIMULTANEOUS COMMUNICATIONS OF ANALOG FREQUENCY-MODULATED AND DIGITALLY MODULATED SIGNALS USING PRECANCELING SCHEME

摘要

In a system for simulcasting digitally modulatedand analog FM signals over the same FM frequency band, theeffect of the analog FM signal on the digitally modulatedsignal in the simulcast is calculated and canceled fromthe latter signal before its transmission. As a result,the digital transmission is free from interference fromthe analog FM signal. Moreover, the digital transmissionis designed in such a manner that the interference causedthereby to the analog FM signal is kept at a minimallevel.