| 摘要 |
<p>PURPOSE:To always automatically obtain the best picture quality and sound quality by detecting a time base fluctuation of a regenerative audio signal and correcting a tracking value to make this time base fluctuation component a min. value. CONSTITUTION:A video signal demodulated by an FM demodulating circuit 32 is separated from a synchronizing signal by a synchronization separating circuit 33. The synchronizing signal (b) separated by the circuit 33 is inputted to a flywheel oscillation circuit 400, where a reference synchronizing signal of an average frequency excluding a fluctuation component of a horizontal frequency of this synchronizing signal is outputted. The reference synchronizing signal is converted into a trapezoidal wave (c), which is then compared by a phase detecting circuit 34 with the synchronizing signal outputted from the synchronization separating circuit 33 and converted into a phase error voltage (d) by a sample-and-hold circuit 35. The voltage (d) is inputted to an optimum tracking amt. calculation processing circuit 20, and the tracking value is controlled to be corrected to a point where the time base fluctuation component becomes min.</p> |
