| 摘要 |
PURPOSE:To eliminate need for an externally mounted component in case of circuit integration by giving output signals of two rectifiers rectifying two systems of input signals respectively to a differential amplifier to apply level comparison in the present state and smoothing the output so as to use only one smoothing capacitor of a small capacitance. CONSTITUTION:Two systems of reproducing head signals a, b of a VTR are inputted respectively to two input terminals 26, 27 and rectified respectively by rectifiers 12, 13. The level of rectified output signals c, d is compared in the signal form as it is by a differential amplifier 28 to obtain a level comparison signal (e). The signal (e) is a signal comprising a difference signal representing the envelope fluctuation of input signals a, b close to a low frequency component or a DC component and comprising a difference signal of harmonics of the frequency component of the input signals a, b. The difference signal component of the envelope fluctuation becomes an envelope comparison output signal. The difference signal of the harmonics of the frequency component of the input signals a, b is an undesired component. The undesired component of the signal (e) is a high frequency signal and attenuated by a capacitor of a smoothing device 29. The capacitor of the smoothing device 29 is a single capacitor of small capacitance.
|
