AUDIO DETECTING CIRCUIT OF MULTI-SYSTEM

摘要

This circuit comprises; a frequency change tool which detects a subcarrier when different subcarrier signal inputted and generates a second harmonic wave from mixing a detected signal into a constant frequency; a AM detecting part which detects audio signal from amplifying and detecting it when AM modulation signal inputted; a switching part which selects audio signal output of the AM detecting part and the frequency change tool according to a system voltage