| 摘要 |
PURPOSE:To avoid the effect of wow and flutter and jitter, by frequency-discriminating a horizontal synchronizing signal of a reproduced video signal for detecting the jitter generated at the recording and reproduction, and eliminating the jitter included in the reproduced audio signal. CONSTITUTION:A monostable multivibrator 35 generates a pulse having a pulse width less than one horizontal scanning period and a 1/2 horizontal scanning period or over while being triggered with the horizontal synchronizing signal. This pulse is applied to a frequency discriminator 36, the fluctuation in the frequency, i.e., the jitter produced at the recording and reproduction is detected as an output level fluctuation, the jitter detecting signal is adjusted into a suitable level with a variable resistor 37 and applied to an inverting input of a subtractor 27. A reproduced audio signal from an FM demodulator 26 is subtracted with the jitter detecting signal at the subtractor 27 and the jitter is eliminated, restored into the audio signal form before the high frequency component is emphasized at a de-emphasis circuit 38 having the inverse characteristic as a pre-emphasis circuit 15 and outputted from an output terminal 39. |
