Abstract: A sync signal correction circuit generates a corrected sync signal which is obtained by correcting a timing of a sync signal on the basis of a time axis variation component (jitter component) of the sync signal separated from a picture signal. The corrected sync signal is used as the sync signal to cause a variation of time axis error of the picture signal to follow a variation of time axis error of an output signal of an automatic frequency control (AFC) circuit which constitutes a monitor device for reproducing and displaying the picture signal, such that the variation of time axis error of the output signal of the AFC circuit and the variation of time axis error of the picture signal of the reproduced picture signal are cancelled each other to prevent jittere from appearing on a display screen.

Abstract: An apparatus for correcting a time base error of a video signal. Signal portions of the video signal are sequentially written in memories with a write clock signal synchronizing with the video signal at specific write timings and sequentially read from the memories with a read clock signal of a constant frequency at specific read timings. At least one of the read timings are changed so that a correlation among the signal portions sequentially read from the memories remains unchanged when a difference between the write and read timings are smaller than a reference value.

Abstract: An apparatus for reproducing video signals from a magnetic recording medium using first and second magnetic heads mutually having different azimuth angles. Here, the video signal is obtained by frequency-multiplexing of a low frequency-converted chrominance signal which is obtained by converting into a low frequency range and phase rotation of a chrominance signal per horizontal scanning period, and a modulated luminance signal, and recorded in the magnetic recording medium. One of video signals picked up by the magnetic heads is selected to obtain a chain of reproduced video signal. Discontinuity is detected if there is in the phase rotation of the low frequency-converted chrominance signal in the reproduced video signal. The low frequency-converted chrominance signal in the reproduced video signal is reconverted into a high frequency range chrominance signal having no phase rotation.

Abstract: An apparatus for compensating a time base error of a video signal. A reference signal of no time base error is generated. A difference between a frequency of the reference signal and a frequency of a horizontal synchronizing signal included in an input analog video signal is detected and then a difference signal is outputted. In response to the difference signal, a phase of the reference signal is controlled. The video signal is sampled, based on the reference signal the phase of which is controlled, thus the video signal is converted into a digital signal in which the difference is cancelled. The digital signal is stored in a memory. And the stored digital signal is read out, based on the reference signal.

Abstract: In a picture-quality improving circuit, a luminance transition is detected on the basis of a luminance signal. Chroma edge characteristics of a color signal are enhanced in accordance with the detected luminance transition. A detection is made as to whether the color signal and the luminance signal are correlated or uncorrelated in transition. When the color signal and the luminance signal are uncorrelated in transition, the enhancement of the chroma edge characteristics of the color signal is interrupted.

Abstract: In a picture-quality improving circuit, a luminance transition is detected on the basis of a luminance signal. Chroma edge characteristics of a color signal are enhanced in accordance with the detected luminance transition. A detection is made as to whether the color signal and the luminance signal are correlated or uncorrelated in transition. When the color signal and the luminance signal are uncorrelated in transition, the enhancement of the chroma edge characteristics of the color signal is interrupted.