| 摘要 |
<p>@ FM-receiver comprising an aerial input having connected thereto, in succession, an RF input stage (1), an IF portion (2), an FM-detector (3) and a stereo decoder (5), also comprising a control signal generating circuit (8-15) and a mono-stereo control circuit (5) connected thereto, the control signal generating circuit (8-15) comprising a multipath reception detector (9, 10) and being connected to the IF portion (2) via a level detector (8), the multipath reception detector (9, 10) comprising an amplitude detector (10) connected to the level detector (8) via a bandpass filter (9). The FM-receiver comprises a noise pulse suppression circuit (4) arranged between the FM-detector (3) and the stereo decoder (5) for keeping the amplitude of the stereo multiplex signal constant during the occurrence of noise pulses. In order to eliminate the disturbing effect of such noise pulses on the mono-stereo control the bandpass filter (9) has a lower 3 dB cut-off frequency of the order of magnitude of 1 KHz and an upper 3 dB cut-off frequency of not more than of the order of magnitude of 10 KHz.</p> |
