| 摘要 |
<p>An FM receiver that is suitable for reducing a transmission bandwidth W F of a bandpass filter to remove adjacent-channel interference, and increasing W F to prevent audio distortion. A detection output signal S OUT is inputted to an HPF 122 when a reception electric field strength signal S M-DC indicates an intermediate or stronger electric field. In a weak electric field, an AC component signal S M-AC , which is extracted from an intermediate signal S IF1 prior to detection and which has fewer high-pass noise components than S OUT , 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 W F of an IFBPF 70 in order to remove adjacent-channel interference. When a small amount of high-pass components is transmitted, W F is increased in order to minimize audio distortion.</p> |
