Patent ID: 6904108

Claim:
A bandpass limiting apparatus in a receiver of the superheterodyne type, in which a plurality of frequency conversions are performed, said apparatus comprising: a bandpass changing means for controlling an intermediate-frequency circuit having a plurality of frequency converting stages outputting intermediate-frequency signals, said bandpass changing means being operable to adjust a passband of an analog intermediate-frequency signal obtained from a final stage of said intermediate-frequency circuit; an A/D conversion means for converting said analog intermediate-frequency signal to a digital signal; a digital signal processing means for adjusting the passband of said intermediate-frequency signal converted to a digital signal by said A/D conversion means; a detection means for obtaining an audio signal detected from said digital signal output by said digital signal processing means; a passband changing means for changing a passband based on an adjustment signal from an adjustment operation part; and a control means responsive to said adjustment signal from said adjustment operation part and operable to cause said passband of said analog intermediate-frequency signals at each said frequency converting stage to change in concert.