FM COMMUNICATION DEVICE WITH AVOIDANCE OF INTERFERENCE BY SUBSTANTIALLY SAME CHANNEL FM SIGNAL

摘要

ABSTRACT OF THE DISCLOSUREAn FM communication device employs alogarithmic amplifier which performs logarithmicconversion of a frequency modulated signal. The beatcomponent level of the output signal of the logarithmicamplifier is checked with a reference level fordetecting interference. With the construction set forthabove, the FM communication device, according to theinvention, detects the ripple of the received FM signalcaused by interference of another FM signal by means ofthe logarithmic amplifier which converts the received FMsignal logarithmically and the detection circuit whichAM-detects the output signal of the logarithmicamplifier, so that the interference can be detected viathe output signal of the detection circuit. In thepreferred construction set forth above, the logarithmicamplifier which is often utilized in a detection systemfor reception magnitude is enough as an amplifiercircuit required for detecting the interference, and nohigh-gain and high-performance amplifier is required.