JPH0357686U - - Google Patents

Description

[Brief explanation of the drawing]

1 to 3 show one embodiment of the color burst PLL circuit of the present invention, in which FIG. 1 is an overall block diagram, FIG. 2 is a detailed block diagram of the sampling pulse generating section, and FIGS. 3 a to h. is a timing chart for explaining operation, and Figure 4 is a conventional color burst PLL.
Block diagram of the sampling pulse generation part of the circuit, Figure 5a
-d are timing charts for explaining the operation of FIG. 8... Continuous wave output section, 10... Sampling pulse generation section, 18... Monostable multivibrator section, 19
...Trigger prohibition section.

Claims (1)

[Claims for Utility Model Registration] A sampling pulse generator that outputs a sampling pulse at the timing of a color burst signal of the video signal based on a pulse edge of a synchronization signal separated and extracted from a composite color video signal; Therefore, a continuous wave output section extracts the burst signal from the video signal and outputs a continuous wave signal having a frequency N times that of the burst signal through PLL control of the extracted burst signal. In the generator, a monostable multivibrator unit outputs the sampling pulse in response to a trigger of the pulse edge, and an equivalent pulse period of a vertical retrace period in which the pulse edge continues at an interval shorter than the horizontal scanning period, and a vertical synchronization period. A color burst PLL circuit comprising: a trigger inhibiting section that inhibits triggering of the multivibrator section during a pulse period.