JPH08256278A - Sc-h phase correction device - Google Patents

Abstract

PURPOSE: To easily adjust a reference composite synchronizing signal without a phase shift and to supply it by comparing a phase of a SYNC signal extracted from the reference composite synchronizing signal with a phase of a burst peak phase pulse thereby extracting a coincident phase. CONSTITUTION: A reference composite synchronizing signal fed to an input terminal 1 is given to a burst separator circuit 2 and a SYNC separator circuit 3, from which a color synchronizing signal (burst signal) and a SYNC signal are respectively extracted, the latter is delayed by a delay circuit 4 and its delay amount is varied by a delay adjustment device 5. A burst pulse generator 8 converts an output signal from the burst separator circuit 2 into a pulse signal and it is delayed by delay circuits 9, 10, the output signal of the generator 8, the outputs of the circuits 9, 10 are given respectively to an AND gate 11, from which a peak phase pulse of burst waveform is obtained. On the other hand, an output of the SYNC delay circuit 4 is given an H pulse generator 12, from which an H pulse is extracted and it is delayed by a delay circuit 13, the delayed signal from the circuit 13 is given to a phase comparator circuit 14, in which the phase of the delayed signal and the phase of the burst waveform peak phase pulse are compared and a coincident phase point between the S and CH signals is extracted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for correcting a phase between a SYNC signal and an H pulse signal (SC-H phase) of a color television synchronizing signal.

[0002]

2. Description of the Related Art As a reference composite synchronizing signal for a plurality of digital video devices, if there is a shift in SC-H phase timing between the devices, a color frame cannot be detected and the digital device may malfunction. In order to solve this problem, a process amplifier is connected between the output terminal of the sync signal generator and the input terminal of the reference sync signal of the digital video equipment to correct the SC-H phase shift so that the digital video equipment operates stably. It is common practice to configure the above.

[0003]

In the above-mentioned prior art,
The process amplifier must be installed in pairs with each digital video device, resulting in a large configuration.
It has the drawback of being expensive.

The present invention eliminates this drawback by adding a simple circuit, so that the adjustment is easier and the SC-H
An object of the present invention is to realize an S-CH phase corrector capable of supplying a reference composite synchronization signal without phase shift.

[0005]

In order to solve the above-mentioned problems, the present invention uses a reference composite sync signal and a color sync signal and an S signal.
Extract the YNC signal, change the delay amount of the SYNC signal,
By comparing the phase with the burst waveform peak phase pulse generated from the color synchronizing signal, the coincident point of the SC-H phase can be extracted and displayed.

[0006]

As a result, even if the reference synchronizing signals with the SC-H phase shift are supplied, for example, RS-1 which is the video signal standard is supplied.
Since it is possible to create a reference composite synchronization signal that completely satisfies the SC-H phase timing standard of the 70A standard and input it to a digital video device, it is possible to prevent malfunction.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG.

The input terminal 1 of the reference composite sync signal is connected to the inputs of the burst separation circuit 2 and the SYNC separation circuit 3. The output of the burst separation circuit 2 is connected to the first input of the mixer 6 which again assembles the reference composite sync signal in the SC-H phase corrector and also to the input of the burst pulse generator 8. The output of the mixer 6 is the signal output terminal 7
Connected to. The output of the SYNC separation circuit 3 is SYNC.
It is connected to the input of the delay circuit 4, the output of the SYNC delay circuit 4 is connected to the second input of the mixer 6 and also to the H pulse generator 12.

The output of the burst pulse generator 8 is connected to the input of the AND gate 11, and further the first delay circuit 9,
It is connected to the input of the second delay circuit 10. Further, the outputs of the first delay circuit 9 and the second delay circuit 10 are connected to the input of the AND gate 11. The output of the AND gate 11 is connected to the first input of the phase comparison circuit 14,
The output of the H pulse generator 12 is connected to the input of the above through an H pulse delay circuit 13. The output of the phase comparison circuit 14 is connected to the input of the one-shot multi-circuit 15, the output of which drives the display 16.

This operation will be described below. From the reference composite sync signal (hereinafter referred to as black burst signal) applied to the signal input terminal 1, only the color sync signal (hereinafter referred to as burst signal) is extracted by the burst separation circuit 2.
Further, the SYNC signal is extracted by the SYNC separation circuit 3. The SYNC signal is delayed by the SYNC delay circuit 4, and the delay amount is changed by the delay adjuster 5. FIG. 2 is a timing chart showing signal waveforms in the respective parts shown in FIG. The burst pulse generator 8 converts the output signal waveform 21 of the burst separation circuit 2 into a pulse signal with the pedestal potential as a slice point, and the signal waveform 22
Get. This signal waveform 22 is a 3-input type AND gate 1
1 as a first input signal. Also, this signal is
The signal is delayed by about 50 ns through the first delay circuit 9, and the second signal of the AND gate 11 is output as a signal as shown in the signal waveform 23.
Input to the input terminal of. Further, it is delayed by about 90 ns through the second delay circuit 10, and is input to the third input terminal of the AND gate 11 as an inverted version of the signal shown in the signal waveform 24. As a result, the output of AND gate 11
A signal shown in the signal waveform 25, that is, a pulse having a phase corresponding to the peak of the verse signal waveform is obtained. This signal is input to the first input terminal of the phase comparison circuit 14 formed of an AND circuit.

On the other hand, the output of the SYNC delay circuit 4 is
The H pulse is extracted by the H pulse generator 12, and the H pulse signal is input to the H pulse delay circuit 13. The H pulse delay circuit 13 delays the falling edge of the SYNC signal by about 5.3 μs so that the burst signal and its delay waveform 26 have the timings shown in the figure, and the signal of the delay waveform 26 has the above-mentioned phase. It is input to the second input terminal of the comparison circuit 14. Therefore, the phase comparison circuit 1
4, a pulse signal is output at the timing shown by the waveform 27 in FIG. 2, but when the H pulse signal is generated after one horizontal scanning period, the burst signal waveform 21 is indicated by the broken line in FIG. As shown, since the phase inversion of 180 ° occurs, the waveform 27 does not occur, and the H phase of the next horizontal scanning period causes the same phase to be generated again, so that the waveform 27 is generated. Further, the phase relationship between the burst signal waveform 21 and the H pulse for outputting the output signal of the phase comparison circuit 14 is such that when the phase difference is within 40 ns, that is, S
This is when the C-H phase is within 40 ns. The phase can be changed by the delay adjuster 5 described above. Therefore, by driving the display 16 through this one-shot multi-circuit 15 having a constant having a width twice the H pulse period, the display is turned on only when the SC-H phase is within 40 ns. You can

As a result, the burst separation circuit 2 and S
The outputs of the YNC delay circuit 4 are mixed by the mixer 6 and returned to the black burst signal again, so that the delay adjuster 5 is adjusted so that the display 16 is turned on. It is possible to output a black burst signal in phase.

[0013]

As described above, according to the present invention, SC-
It is possible to correct the H phase of the black burst signal with the H phase deviated, to adjust the SC-H timing within 40 ns, and to easily produce a signal that satisfies the RS-170A standard with a simpler circuit configuration. .

[Brief description of drawings]

FIG. 1 is a diagram showing a block configuration of an embodiment of the present invention.

FIG. 2 is a diagram showing a waveform timing chart of each block for explaining the operation of the present invention.

[Explanation of symbols]

 1 Input Terminal 2 Burst Separation Circuit 3 SYNC Separation Circuit 4 SYNC Delay Circuit 5 Delay Adjuster 6 Mixer 7 Output Terminal 8 Burst Pulse Generator 9 Delay 1 Circuit 10 Delay 2 Circuit 11 AND Gate 12 H Pulse Generator 13 H Pulse Delay Circuit 14 Phase comparison circuit 15 One-shot multi circuit 16 Display

Claims (2)

[Claims] 1. A means for separating a color sync signal and a SYNC signal (video sync signal) from a reference composite sync signal of a video signal, a means for pulsing a waveform peak phase of the color sync signal, and a SYNC signal phase. Delay means, means for extracting an H pulse signal (horizontal synchronizing pulse signal) from the delayed SYNC signal, means for delaying the H pulse signal, delayed H pulse signal and waveform peak pulse of the color synchronizing signal And a means for displaying a phase match when the phases match and a means for mixing and outputting the separated color synchronization signal and the delayed SYNC signal. SC-H phase corrector. 2. The SC-H phase corrector according to claim 1, wherein the means for delaying the H pulse signal delays the H pulse signal by about 5.3 μs.