Patent ID: 7664197

Claim:
An AM receiving circuit comprising: an intermediate frequency unit that converts a broadcast wave signal into an intermediate frequency signal and amplifies the intermediate frequency signal; an AGC (Automatic Gain Control) circuit that generates a signal-meter signal to set a gain of the intermediate frequency unit depending on electric field intensity of the broadcast wave signal; an AM detecting unit that detects the intermediate frequency signal output from the intermediate frequency unit to produce an audio signal; an intermediate frequency signal intensity detecting unit that generates an intermediate frequency signal carrier intensity signal indicating an intensity of a carrier frequency component of the intermediate frequency signal output from the intermediate frequency unit; and, a sound quality compensating unit including: a filter unit that extracts a predetermined frequency band of the audio signal; an amplifying unit that boosts or attenuates the audio signal in the predetermined frequency band extracted from the filter unit; and a controlling unit that controls filter characteristics of the filter unit and sets a boosting function or an attenuating function of the amplifying unit, depending on the signal-meter signal and the intermediate frequency signal carrier intensity signal.