Patent ID: 6799022
Filing Date: 2004-09-28
Classification: H04B

Abstract:
A input circuit arrangement for an AM/FM radio receiver, the AM/FM radio receiver having an FM input circuit for receiving FM input signals, and an AM input circuit for receiving AM input signals, the input circuit arrangement comprising:a circuit for selecting an FM frequency away from an AM frequency at an antenna input, the circuit for selecting having an output; an FM intermediate frequency rejection circuit having another output and being coupled to the output of the circuit for selecting the FM frequency away from the AM frequency; an AM image frequency rejection circuit coupled downstream from the FM intermediate frequency rejection circuit; and a plurality of PIN diodes for switching between AM operation and FM operation, wherein: at least one of the plurality of PIN diodes connects the another output of the FM intermediate frequency rejection circuit for high-frequency signals to ground for FM operation; and a control voltage is applied to at least one of the plurality of PIN diodes for providing automatic gain control between the FM intermediate frequency rejection circuit and the AM image frequency rejection circuit for AM operation.