| 摘要 |
PURPOSE:To achieve excellent video quality without beat, by constituting the system with a circuit frequency-multiplying an FM signal, filter circuit picking up fundamental wave component from the multiplied FM signal, and circuit frequency-detecting said filter circuit output signal. CONSTITUTION:An FM signal obtained from a reproducing amplifier is inputted to a frequency multiplier 23 and after converted into n-times (where; n is an integer, n>=3) the carrier frequency of the FM signal, it is applied to a band-pass filter 24, where only n-times frequency signals pass, and this passing signal is inputted to a frequency detector 25. After demodulation at said frequency detector 25, the signal is applied to a low-pass filter 26 and a video signal is obtained. Thus, unnecessary carrier component, side band or its harmonic components are all attenuated, no beat is produced and the video quality of reproduction with excellent S/N can be achieved. |
