| 摘要 |
<p>A circuit for sensing pulse-like noises entering an AM receiver, by which the freedom of a configuration is improved and malfunctions are prevented. The circuit, which is used in an AM receiver, provided with an evelope detector (108) for envelope-detecting the intermediate frequency signal, and outputs a gate signal for removing the pulse-like noise signal included in the output signal of the envelope detector (108), includes a high-pass filter (31), an amplifier (32), a level sensing section (33), and a band-pass filter (34). The first high-pass filter (31) blocks an envelope-detected signal fed from the envelope detector (108), and extracts the pulse-like noise signal from the output signal of the envelope detector (108). The amplifier (32) amplifies the extracted pulse-like noise signal. The level sensing section (33) senses the level of the amplified pulse-like noise signal, and when the level exceeds a predetermined value, outputs the gate signal. The band-pass filter (34) extracts the envelope-detected signal from the output signal of the envelope detector (108), adjusts the amplification factor of the amplifier (32) and controls the level of the pulse-like noise signal to a fixed value. <IMAGE></p> |
