Patent ID: 6373398
Filing Date: 2002-04-16
Classification: G07C,H03D

Abstract:
A receiver comprising:a first converter for performing frequency conversion on FM and AM signals to be used for a keyless entry system and a high frequency signal of FM broadcast to be used for an automobile audio system; an IF limiter amplifier for amplifying an output signal of said first converter and subsequently limiting an amplitude of the output signal to a predetermined level; a second converter for performing frequency conversion on a high frequency signal of AM broadcast to be used for said automobile audio system; an IF amplifier provided with an AGC function for amplifying an output signal of said second converter; an FM detector circuit for FM-detecting an output signal of said IF limiter amplifier; an AM detector circuit for AM-detecting one of the output signal of said IF limiter amplifier and an output signal of said IF amplifier; a selector for selecting one of the output signal of said IF limiter amplifier and the output signal of said IF amplifier; and a microcomputer for controlling the operation of locking and unlocking a door of an automobile on the basis of one of an FM keyless signal output from said FM detector circuit and an AM keyless signal output from said AM detector circuit; wherein said selector selects the output signal of said IF limiter amplifier when said first converter performs frequency conversion on the AM signal and selects the output signal of said IF amplifier when said first converter performs frequency conversion on the FM signal or the high frequency signal for FM broadcast.