| 摘要 |
PURPOSE:To prevent a luminance signal and a chroma signal from being timewise shifted, by converting a reproducing signal for high frequency at the reproductionof PAL signals in a VTR, passing the signal through a broad band delay line, and using the signal for a main signal not only for dropout compensation. CONSTITUTION:Signals are switched at a head changeover circuit 11 via heads 1, 2 and preamplifiers 9, 10 with a head switching pulse and become continuous signals. A part of the signals passes through a low pass filter 13 to be a chroma signal (b), which is frequency-converted at a high band conversion circuit 22, and applied to a mixing circuit 26 via comb type filters 23, 24. A luminance signal is obtained from the other output via an automatic gain control circuit 35, a high frequency conversion circuit 36, an oscillator 37 and an amplifier 100, the dropout is detected at a dropout detection circuit 56 at the next stage, and the output controls a switch 39. Normally, a 1H delay luminance signal B through a vertical corelation circuit 101 is dropped out, then a luminance signal A not through a delay line is outputted and inputted to a mixing circuit 26 via a switch 51, and a video signal (v) is obtained. |
