JPH0787356A - Synchronizing signal generation device - Google Patents

Abstract

PURPOSE:To output a video which is always synchronized even in the case of the signal of special reproduction by switching a synchronizing signal according to whether a pulse is outputted at a specified period at every field. CONSTITUTION:Horizontal synchronous/vertical synchronous/equivalent pulse generation devices 1, 2 and 3 generate the synchronizing signals composed of the horizontal synchronous/vertical synchronous/equivalent pulses and generate the synchronizing signal (a) through a switching device 5. A decoder for simple synchronizing signal 6 counts an H/2 pulse, and decodes timing when the horizontal synchronous pulse is masked. A gate 17 synthesizes the output of the device 1 with the output of the decoder 6, and a simple synchronizing signal generation device 21 generates a simple synchronizing signal (b). A video signal discrimination device 7 counts the H/2 pulse and discriminates the signal to be a standard NTSC signal or a non-standard NTSC signal. When it is the standard NTSC signal, a switching circuit 8 is changed over to the signal (a), and to the signal (b) when it is the non-standard NTSC signal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a synchronizing signal generator in a video signal processor.

[0002]

2. Description of the Related Art A sync signal generator in a conventional video signal processor will be described below with reference to the drawings. FIG. 5 is a block diagram showing a conventional synchronizing signal generator.

In FIG. 5, 1 is a horizontal synchronizing pulse generator, 2 is a vertical synchronizing pulse generator, 3 is an equalizing pulse generator, 4 is a switching signal generator, and 5 is a switching device.

FIG. 4 is a block diagram showing the structure of a video signal processing device using the synchronizing signal generator shown in FIG. In FIG. 4, 9 is a clock recovery device including a PLL, 10 is an A / D converter, 11 is a signal processing device, 12 is a D / A converter, 13 is an encoder, 14 is a burst flag pulse generator, and 15 is a block. The ranking pulse generator, 16 is a synchronizing signal generator.

When the NTSC video signal is input to the video signal processing device shown in FIG.
A clock of 3 MHz, a pulse that is output for each horizontal scanning period (hereinafter, H pulse), a pulse of a frequency that is twice that (hereinafter, H / 2 pulse), and a pulse that is output for each field (hereinafter, V pulse). The A / D converter 10 converts the input video signal from analog to digital, and the signal processor 11 processes the output signal of the A / D converter 10. Then, the 12 D / A converters convert the output signal of the signal processing device 11 into analog. Also, 1
In the burst flag pulse generator 4 and the blanking pulse generator 15 and the sync signal generator 16, the burst flag pulse and blanking pulse necessary for encoding the video signal based on the output of the clock reproducing device 9 are used. , Is generating a sync signal.

The outputs of the A / D converter 10, burst flag pulse generator 14, blanking pulse generator 15, and sync signal generator 16 are input to the encoder 13 to output a video signal.

Next, a conventional synchronizing signal generator 16 will be described with reference to FIGS. The clock and the H pulse obtained by the clock regenerator 9 of FIG. 4 are input to the horizontal sync pulse generator 1, the vertical sync pulse generator 2, and the equalization pulse generator 3 to count 910 clocks during one horizontal scanning period. Horizontal sync pulse, vertical sync pulse,
The timing for generating the equalization pulse is decoded. H
/ 2 pulse and V pulse are input to the switching signal generator 4, 525 H / 2 pulses are counted in one field period, the timing for switching the horizontal synchronizing pulse, the vertical synchronizing pulse and the equalizing pulse is decoded, and the switching signal is generated. To occur.

The switching device 5 switches the horizontal synchronizing pulse, the vertical synchronizing pulse and the equalizing pulse based on the switching signal of the switching signal generating device 4, and is composed of a horizontal synchronizing pulse, a vertical synchronizing pulse and an equalizing pulse. Generates a sync signal.

[0009]

However, in the case of a video signal which cannot count 525 H / 2 pulses in one field period, such as a non-interlaced signal or a special reproduction signal such as VTR / LD, a switching signal generator is provided. In 4, the timing of switching the vertical synchronizing pulse and the equalizing pulse cannot be decoded, and therefore, the switching signal is not generated, so that the synchronizing signal cannot be generated. Therefore, there is a problem in that the output video signal causes disturbance in synchronization.

The present invention solves the above-mentioned conventional problems. Even when the input video signal is a non-interlaced signal or a signal for special reproduction such as VTR / LD, synchronization is always maintained. It is an object of the present invention to provide a synchronization signal generation device for outputting a captured image.

[0011]

In order to achieve the above object, the present invention provides a synchronizing signal generator for generating a synchronizing signal composed of a horizontal synchronizing pulse, a vertical synchronizing pulse and an equalizing pulse, A device for generating a sync signal composed of only horizontal sync pulses (hereinafter referred to as a simple sync signal) (hereinafter referred to as a simple sync signal generator), and an input video signal being H / 2 in one field period. A discriminating device for discriminating whether or not a video signal capable of counting 525 pulses and a discriminating signal by the discriminating device outputs a synchronizing signal by the synchronizing signal generating device when H / 2 pulses can be counted for 525 in one field period. However, when 525 H / 2 pulses cannot be counted in one field period, a switching device for switching and outputting the simple synchronization signal by the simple synchronization signal generator. It is those with a.

[0012]

According to the present invention, the input video signal is 1
It is determined whether or not the video signal is capable of counting 525 H / 2 pulses in the field period, and H / H is counted in one field period.
When 2 pulses can be counted for 525, a sync signal composed of a horizontal sync pulse, a vertical sync pulse, and an equalization pulse is generated, and H / 2 pulses are set to 5 in one field period.
When 25 counts cannot be made, a simple sync signal composed only of horizontal sync pulses is generated by switching to prevent a sync flow of video output.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A sync signal generator in a video signal processor according to an embodiment of the present invention will be described below with reference to the drawings. The components denoted by the same reference numerals as those in FIGS. 4 and 5 are the same as those described above, and thus the description thereof is omitted here.

Reference numeral 6 denotes a simple sync signal decoder, which is a gate 1
7 and the simple sync signal generator 21. Reference numeral 7 is a video signal discriminating device, and switching device 8 is a discriminating signal outputted from the video signal discriminating device 7, and a synchronizing signal a outputted from the synchronizing signal generating device 22 and a simple synchronizing signal outputted from the simple synchronizing signal generating device 21. b is switched and output.

The operation of the synchronizing signal generating device in the video signal processing device having the above-described blocks will be described below. In the horizontal sync pulse generator 1, the vertical sync pulse generator 2, and the equalization pulse generator 3,
A synchronizing signal composed of a horizontal synchronizing pulse, a vertical synchronizing pulse and an equalizing pulse as shown in FIG. 2 is generated. In the simple sync signal decoder 6, the clock recovery device 9
The H / 2 pulse of the output of 1 is counted, and the timing for masking the horizontal synchronizing pulse is decoded so as to generate the simple synchronizing signal b shown in FIG. Then, the gate 17 synthesizes the output of the horizontal sync pulse generator 1 and the output of the simple sync signal decoder 6, and the simple sync signal generator 21 generates the simple sync signal b.

On the other hand, in the video signal discriminating apparatus 7, H / H based on the V pulse from the output of the clock reproducing apparatus 9 in FIG.
When 2 pulses are counted and if 525 can be counted in one field period, the input video signal is a standard NTSC signal, and if 525 cannot be counted in one field period, it is determined that the input video signal is a non-standard NTSC signal, and a determination pulse is output. . When it is determined that the input video signal is a standard NTSC signal based on the determination pulse of the video signal determination device 7, the synchronization signal a generated by the synchronization signal generation device 22 is
When the input video signal is determined to be a non-standard NTSC signal, the simple sync signal b generated by the simple sync signal generator 21 is switched and output.

As described above, according to the present embodiment, even when the input video signal is the standard NTSC signal, the output video does not cause the synchronous flow even when it becomes the non-standard NTSC signal.

[0018]

As is apparent from the above embodiments, the synchronizing signal generating device in the image signal processing device of the present invention is synchronized even when the input image is a non-interlaced signal or a non-standard NTSC signal such as special reproduction of VTR. It can provide excellent output video.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a synchronization signal generator according to an embodiment of the present invention.

FIG. 2 is a diagram showing a waveform of a synchronization signal output from the device.

FIG. 3 is a diagram showing a waveform of a simple synchronization signal output from the device.

FIG. 4 is a block diagram showing a configuration of a video signal processing device.

FIG. 5 is a block diagram showing a configuration of a conventional synchronization signal generator.

[Explanation of symbols]

 1 Horizontal sync pulse generator 2 Vertical sync pulse generator 3 Equalization pulse generator 4 Switching signal generator 5 Switching circuit 6 Simple sync signal decoder 7 Video signal discriminating device 8 Switching circuit 17 Gate 21 Simple sync signal generating circuit

Claims (1)

[Claims] 1. A means for obtaining a clock, a pulse output for each horizontal scanning period and a pulse output for each field from a video signal, and a horizontal output from the clock and a pulse output for each horizontal scanning period. Sync pulse, vertical sync pulse, each pulse generating means for generating an equalization pulse,
First synchronization signal generating means for generating a synchronization signal composed of the horizontal synchronization pulse, vertical synchronization pulse and equalization pulse, and second synchronization signal for generating a synchronization signal composed of the horizontal synchronization pulse. Generating means, discrimination means for discriminating whether or not the pulse output for each field is output at a specific cycle, and pulse output for each field by the determination means is output at a specific cycle. Switching means for outputting the synchronization signal generated by the first synchronization signal generating means when it is determined that the synchronization signal is generated, and outputting the synchronization signal generated by the second synchronization signal generation means for the determination that the synchronization signal is not output. Signal generator equipped with.