| 摘要 |
PURPOSE:To obtain a reproduction state of high fidelity by obtaining an indication value corresponding to a sense of hearing distortion by extracting only a signal component of approximate 19kHz in a signal outputted by a FM demodulstor and then by displaying a multipath distortion value by its variation value. CONSTITUTION:A demodulated signal from FM demodulator 4 is supplied to band- pass BPF of 19kHz in the center frequency of its passing band, the output signal of which is supplied to amplitude demodulator DET to an envelope of a 19kHz signal amplitude-modulated by interference distortion. The detection signal of it is supplied to coupling capacitor C, where it direct-current component is removed, and a driving signal for indicator M is obtained through rectifying filtration SCC, thereby performing display. Therefore, interference distortion caused when a signal of a band of hundreds to thousands kHz in a modulated signal is relatively small in modulation degree can excellently be extracted at about 19kHz. |
