JPH0170483U - - Google Patents

Description

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of an embodiment of this invention. FIG. 2 is a timing chart for explaining the operation of one embodiment of this invention. FIG. 3 is a block diagram showing the configuration of a conventional example. FIG. 4 is a timing chart for explaining the operation of the conventional example. 1...Variable delay circuit, 7...Integrator, 8...Voltage controlled oscillator, 9...Horizontal synchronization signal separation circuit, 1
0... Extracting circuit, 23... Oscillator, 24... Counter, 25... Flip-flop, 26... Shift register, 28, 34 and 35... D flip-flop, 30, 31 and 32... Frequency divider,
40...Phase comparator.

Claims (1)

[Claims for Utility Model Registration] (1) A video device comprising a variable delay means, which detects a time base error in a composite video signal detected from a video disk, and controls the amount of delay of the variable delay means in a direction in which the time base error approaches zero. The time base correction circuit of the disc playback device includes an oscillator that oscillates at a frequency that is at least twice the frequency of the color burst signal, and a horizontal synchronizing signal in the composite video signal that has passed through the variable delay means; pulse generating means for generating a pulse having a width ranging from the leading edge of the horizontal synchronizing signal to the color burst signal by counting the output of the horizontal synchronizing signal up to a predetermined value; and inverting the phase of the color burst signal every horizontal scanning period. a phase inversion means, a latching means for latching the output from the pulse generation means with an output from the phase inversion means, a frequency division means for dividing the output from the oscillator into a frequency of a horizontal synchronizing signal; It is characterized by comprising phase comparison means for comparing the phases of the output from the latch means and the output from the frequency dividing means, and controlling the delay amount of the variable delay means in accordance with the phase comparison output from the phase comparison means. A time base correction circuit for a video disc playback device. (2) The scope of the utility model registration claim, characterized in that the phase comparison means is equipped with a control means that enables the phase comparison operation only in the period before and after the presence of the color burst signal, and only when the color burst signal is present. A time base correction circuit for a video disc playback device according to item 1.