Mikrocomputerbasiertes Trägererfassungssystem eines drahtlosen Telefons

摘要

A microcomputer 160' in a radio frequency (RF) signal receiver, such as a cordless telephone set, periodically samples a received baseband audio signal to determine its frequency content. The microcomputer 160' uses at least one predetermined frequency threshold value, and determines that the RF signal is present if the output signal contains signals no higher in frequency the frequency threshold value, and determines that the RF signal is absent if the output signal contains signals higher in frequency than the frequency threshold value. The circuit is useful in either a base unit or a handunit of a cordless telephone set.