发明授权
US07860479B2 FM receiver 有权
FM接收机

FM receiver
摘要:
An FM receiver that is suitable for reducing a transmission bandwidth WF of a bandpass filter to remove adjacent-channel interference, and increasing WF to prevent audio distortion. A detection output signal SOUT is inputted to an HPF 122 when a reception electric field strength signal SM-DC indicates an intermediate or stronger electric field. In a weak electric field, an AC component signal SM-AC, which is extracted from an intermediate signal SIF1 prior to detection and which has fewer high-pass noise components than SOUT, is inputted to the HPF 122. A control circuit 120 detects a case as an adjacent-channel interference state when a large amount of high-pass components passes through the HPF 122, and reduces WF of an IFBPF 70 in order to remove adjacent-channel interference. When a small amount of high-pass components is transmitted, WF is increased in order to minimize audio distortion.
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