Noise eliminating circuit |
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| 申请号 | JP2364480 | 申请日 | 1980-02-26 | 公开(公告)号 | JPS56119506A | 公开(公告)日 | 1981-09-19 |
| 申请人 | Matsushita Electric Ind Co Ltd; | 发明人 | IIZUKA SHIYOUGO; | ||||
| 摘要 | PURPOSE:To eliminate the noise other than the pulse noise, by detecting frequency components and amplitude components of the demodulation signal and by synthesizing these components to obtain the demodulation output after band limiting. CONSTITUTION:The output of demodulating circuit 22 of the radio device is branched into two, and one is input to amplitude limiting amplifier 23, and the other is input to envelop detecting circuit 28. The signal input to amplifier 23 is amplified into a fixed amplitude and is subjected to amplitude limiting and becomes the reference signal of the phase synchronizing circuit consisting of phase comparing circuit 24, LPF25, and voltage control oscillator 26. Therefore, the output of oscillator 26 has a fixed amplitude, and the frequency coincides with the output frequency of circuit 22, and the spectrum purity becomes higher than that of circuit 22. The output of oscillator 26 becomes the input of electronic volume 27. The other demodulation signal is detected by circuit 28 and has noise components eliminated by LPF29 and has only fluctuation factors of the amplitude taken out and has the phase matched to the signal of frequency components of the phase synchronizing circuit by phase shifting circuit 210, and the signal from oscillator 26 is subjected to amplitude modulation by volume 27, and the signal which is equivalent to the signal of circuit 22 and has a small noise is output from terminal 211. | ||||||
| 权利要求 | |||||||
| 说明书全文 | |||||||
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