JP3020224B2 - Synchronous signal separation device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a synchronizing signal separating apparatus for separating and reproducing a vertical synchronizing signal from an arbitrary composite synchronizing signal included in an analog video signal.

[Prior Art and its Problems] FIG. 6 shows an example of a conventional synchronizing signal separating apparatus for explaining a synchronizing signal separating apparatus for digitally separating and reproducing a vertical synchronizing signal from a composite synchronizing signal without using an integrator. It is a block diagram.

The in FIG. 6 is a trigger any composite synchronizing signal S ₁ or S _'1 input to the composite sync signal S ₁ or S a' rise of ₁ included in the analog video signal, from the synchronization period t ₁ of the horizontal synchronizing signal水平 of one cycle t ₂ of the horizontal sync signal
Shorter than, the one-shot pulse generator for generating a pulse S ₈ of a constant pulse width T, 2 inputs the composite synchronizing signals S ₁ or S _'1 and the output pulses S ₈ of the one-shot pulse generator 1, the Pulse from wasshot pulse generator 1
Sampled at the trailing edge of the S _8, the composite synchronizing signals S ₁ or S '
The L level when ₁ is at L level, when the H level is the sampling device for separating a vertical synchronizing signal S ₂ to the H level.

FIG. 7 is a timing chart in a case where the in synchronizing signal separation device 6 Figure, generates a pulse S ₈ at the rising of the one-shot pulse inputted to the generator 1 composite synchronizing signal S _1. FIG. 7 (a) shows a case where a composite synchronizing signal having a cutting pulse is input, and FIG. 7 (b) shows a case where a composite synchronizing signal without a cutting pulse is input.

That is, when the composite synchronizing signals S ₁ with a notch pulse P is input to the one-shot pulse generator 1 than this pulse S ₈
Is output. The pulse S ₈ and the composite sync signal S ₁ is input to the sampling unit 2, a composite sync signal S vertical sync signal S ₂ contained in the ₁ is taken out is separated (see FIG. 7 (a)).

The composite synchronizing signal S _'1 with no pulse cuts the input to the one-shot pulse generator 1, which pulse S ₈ is outputted from. This pulse S ₈ and the composite synchronization signal S ′ ₁
There are input to the sampling unit 2, a composite sync signal S vertical sync signal S ₂ contained in the ₁ is taken out is separated (FIG. 7 (b) refer).

Although FIG. 7 (a) the vertical sync signal S ₂ is extracted correctly separated, FIG. 7 (b) in the sampled vertical sync signal S _2, the first composite synchronizing signal S _'1 video period unchanged until a horizontal synchronizing signal, the first horizontal synchronization signal would be included in the vertical synchronization period t _s, it is impossible to obtain the vertical sync signal S ₂ of the correct timing.

In the prior art performed in this manner by the digital, there is a problem that particularly cut from the composite sync signal S _'1 with no pulse can not be separated play at the correct time vertical synchronization signal S _2.

An object of the present invention is to correctly separate play vertical sync signal S ₂ from the composite synchronizing signal S _'1 with no pulse cuts.

[Means for solving the problem]

Synchronizing signal separating device according to claim 1 of the present invention, the composite synchronizing signals S ₁ or S _'1 are contained in the video signal of the analog input as shown in FIG. 1-FIG. 3, the vertical same signal in the synchronizing signal separation device for separating play S _2, generates the horizontal synchronizing signal of the synchronous longer than the period, and a pulse of short constant pulse width than half of one cycle of the horizontal synchronizing signal at the time of the level change of the input signal A pulse generator that samples the level of the composite synchronization signal and outputs the sampled value at the end of the pulse generated by the pulse generator; and a change in the output signal level of the sampler. A polarity switch for inverting the level of the composite synchronization signal and outputting the inverted signal as the input signal of the pulse generator.

Further, the synchronization signal separating device according to claim 2 of the present invention,
In a synchronizing signal separating apparatus for separating a horizontal synchronizing signal and a vertical synchronizing signal from a composite synchronizing signal obtained by synthesizing a horizontal synchronizing signal and a vertical synchronizing signal, a synchronization period of the horizontal synchronizing signal is triggered by a rise of the composite synchronizing signal A first pulse generator that generates a pulse having a constant pulse width longer than one half of one cycle of the horizontal synchronizing signal and a falling edge of the composite synchronizing signal as a trigger, and A second pulse generating a pulse having a constant pulse width that is long and shorter than half of one cycle of the horizontal synchronizing signal.
A pulse generator and a generated pulse of one of the first pulse generator and the second pulse generator are input, and at the end of the generated pulse, the level of the composite synchronizing signal is sampled and the sampled value is calculated. And a generator that switches between a pulse generated by the first pulse generator and a pulse generated by the second pulse generator in accordance with a change in the output signal level of the sampler and is input to the sampler. And a signal switch for making a pulse.

(Operation) In the synchronization signal separation device according to claim 1 of the present invention, the level signal sampled by the sampling device is fed back to the polarity switching device, and the composite synchronization is performed by the polarity switching device according to the level change of the level signal. signal S ₁ or S 'polarity of ₁ is inverted, the composite synchronizing signal S ₁ or S during inversion period t _s' polarity of ₁ pulse S ₃ which has been inverted is outputted from the polarity switch. The output pulse S ₃ is than this pulse S ₄ is input to the pulse generator is outputted as a trigger, the sampling unit by the output pulse S ₄ samples the composite sync signals S ₁ or S _'1, the composite synchronizing signal S ₁ or S _'1 from the separated vertical synchronizing signal and a horizontal synchronizing signal will be output.

Also, in the synchronous signal separating device according to claim 2 of the present invention, the pulse generator 1a to rise and fall of the composite synchronizing signals S ₁ or S _'1 as a trigger pulse to 1b
S _5, S ₆ to generate, switches the output pulse S _5, S ₆ of the signal switch to the sampled level signal is fed back by the sampling device, the sampling device by the output pulse S ₇ of the signal switcher 4 becomes the 'sampling a _1, a composite sync signal S ₁ or S' composite synchronizing signal S ₁ or S outputs from ₁ separates the vertical synchronizing signal and a horizontal synchronizing signal.

〔Example〕

 Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram for explaining an embodiment of the method and apparatus of the present invention, and FIG. 2 is a time chart of input / output signals of a polarity switch in the present invention.

3 is a polarity switching device for inverting the polarity of the composite synchronizing signals S ₁ to the synchronization period t _s of separated vertical synchronizing signal S ₂ in FIG. 1, the polarity of the composite synchronizing signals S ₁ to synchronization (inverted) during t _s and outputs a pulse S ₃ obtained by inverting the. 1 one-shot pulse generator for generating pulses S ₄ the rise of output pulses S ₃ polarity switch 3 as a trigger, 2 samples the composite sync signals S ₁ at the trailing edge of the one-shot pulse S _4, composite sync when the signal S ₁ is L level to L level and outputs the H level, resulting in a sampling device and outputting the separated vertical synchronizing signal S ₂ and the horizontal synchronizing signal.

If synchronization period t _s polarity switch 3 is a vertical synchronizing the composite synchronizing signals S ₁ inputted thereto is separated signals S _2, inverted, to the one-shot pulse generator 1 as it is as long as video period and outputs a pulse S _3. And trigger rising edge of pulse S ₃ from the one-shot pulse generator 1, the polarity switching unit 3, longer than the synchronization period t ₁ of the horizontal synchronizing signal, it is shorter than one-half of one cycle t ₂ of the horizontal synchronizing signal , it generates a pulse S ₄ having a constant pulse width T. At the trailing edge of the pulse S ₄ entered the sampler 2, and outputs a composite synchronizing signals S ₁ separates the sampled vertical sync signal S _2.

FIG. 3 (a) is a time chart when a composite synchronizing signal having a cutting pulse is input to the synchronizing signal separating device of FIG. Output pulse S ₃ only polarity switch 3 during the synchronization period t _s of the vertical sync signal S ₂ is inverted as can be seen from the FIG. 3 (a) shows a timing chart of. That vertical rising of the composite synchronizing signals S ₁ synchronous signal S ₂
Sample the beginning of the synchronization period t _s of the composite synchronization signal
And sampling the end of synchronization period t _s of the vertical sync signal S ₂ on the falling of S _1. Thus, it is possible to obtain the vertical sync signal S ₂ of the correct timing.

FIG. 3 (b) is a time chart when a composite synchronizing signal without a cutting pulse is input to the synchronizing signal separating device of FIG. In this case also Figure 3 vertical synchronizing signal S ₂ at the right time as (a) are taken out are separated.

Figure 4 is an explanatory block diagram showing a configuration of a second embodiment of the present invention apparatus, 1a is the one-shot pulse generator for generating a pulse S ₅ as a trigger to the rise of the composite sync signal S _1, 1b is composite sync a one-shot pulse generator for generating a pulse S ₆ the fall of the signals S ₁ as a trigger. 4
Inputs the vertical synchronizing signal S _2, 2 one-shot pulse generator 1a, a signal switch for switching the pulse S _5, S ₆ from 1b. 2 is a trailing edge of the pulse S ₇ from signal switch 4, a sampler for sampling the composite synchronizing signal S _1.

The second embodiment in place of the polarity switching unit 3 of the first embodiment of FIG. 1, in the case of using the signal switch 4, multiplied by the feedback in the signal switch 4 to the separated vertical sync signal S ₂ ing. A one-shot pulse generator 1a for generating a pulse S ₅ the entered rise of the composite sync signals S ₁ as a trigger, a one-shot pulse generator 1b which generates a pulse S ₆ as a trigger falling edge of the composite synchronizing signals S ₁ Then, the generated pulses S ₅ and S ₆ are input to the signal switch 4, and in the synchronization period t _{s of} the separated vertical synchronization signal S ₂ , a pulse S ₆ triggered by the falling edge of the composite synchronization signal S ₁ is provided, pulse S ₅ was triggered by rising edge of the composite synchronizing signals S ₁ in image period
Are switched by the signal switching unit 4 and the sampling timing by the sampling unit 2 is changed.

FIG. 5 is a time chart showing the operation of the second embodiment of FIG. FIG. 5 (a) shows a case where a composite synchronizing signal having a cutting pulse is input, and FIG. 5 (b) shows a case where a composite synchronizing signal without a cutting pulse is input. Pulse interval T of the one-shot pulse is longer than the synchronization period t ₁ of the horizontal synchronizing signal, it is shorter than one-half of one cycle t ₂ of the horizontal synchronizing signal.

In the second embodiment performs an operation for separating the vertical sync signal S ₂ by switching the pulse S _5, S ₆ without inverting the composite synchronizing signals S ₁ inputted.

INDUSTRIAL APPLICABILITY The present invention is particularly effective for a synchronizing signal separating device such as a CRT, a video digitizing device, and a video printer that handles many video signals.

〔The invention's effect〕

According to the present invention as described above, that the composite synchronizing signals S ₁ with a serration pulses can be correctly separated reproduced vertical synchronizing signal S _2, of course, it cuts the vertical sync signal S ₂ from the composite synchronizing signal S _'1 with no pulse Can be correctly separated and reproduced.

[Brief description of the drawings]

FIG. 1 is an explanatory block diagram showing the configuration of an embodiment of the apparatus of the present invention, FIG. 2 is a time chart of input / output signals of a polarity switch in the present invention, and FIG. FIG. 3B is a time chart when a composite synchronizing signal having a cut pulse is input to the signal separating device, and FIG. FIG. 4 is an explanatory block diagram showing the configuration of a second embodiment of the apparatus of the present invention. FIG. 5 (a) shows a case where a composite synchronizing signal having a cutting pulse is input, and FIG. 5 (b) shows a cutting. When the composite synchronizing signal without a pulse is input, the second synchronizing signal shown in FIG.
FIG. 6 is a time chart showing the operation of the embodiment, FIG. 6 is a block diagram for explaining an example of the configuration of a conventional apparatus, and FIG. 7 (a) shows a case where a composite synchronizing signal having a cutting pulse is input. 6B is a timing chart showing the operation of the conventional device shown in FIG. 6 when a composite synchronizing signal without a cutting pulse is input. S ₁ , S ′ ₁ …… Composite synchronization signal, S ₂ …… Vertical synchronization signal, 1,1
a, 1b ...... (one shot) pulse generator, 2 ...... sampler, 3 ...... polarity switch, t _s ...... vertical sync (inversion) period, t ₁ ...... synchronizing period of the horizontal synchronizing signal, t ₂ ... 1 cycle of horizontal synchronizing signal, T: constant pulse width, 4: signal switch, S ₃ , S ₄ , S ₅ , S ₆ , S ₇ .

Claims (2)

(57) [Claims] 1. A synchronizing signal separating apparatus for separating a horizontal synchronizing signal and a vertical synchronizing signal from a composite synchronizing signal in which a horizontal synchronizing signal and a vertical synchronizing signal are compounded. A pulse generator for generating a pulse having a fixed pulse width longer than a synchronization period and shorter than half of one cycle of the horizontal synchronization signal; and a level of the composite synchronization signal at an end of a pulse generated by the pulse generator. And a polarity switcher that inverts the level of the composite synchronization signal in accordance with a change in the output signal level of the sampler and outputs the inverted signal as the input signal of the pulse generator. And a synchronizing signal separating device. 2. A synchronizing signal separating apparatus for separating a horizontal synchronizing signal and a vertical synchronizing signal from a composite synchronizing signal obtained by synthesizing a horizontal synchronizing signal and a vertical synchronizing signal. A first pulse generator for generating a pulse having a constant pulse width longer than a synchronization period of the synchronization signal and shorter than half of one cycle of the horizontal synchronization signal; A second pulse generator that generates a pulse having a constant pulse width longer than the synchronization period of the horizontal synchronization signal and shorter than half of one cycle of the horizontal synchronization signal; and either the first pulse generator or the second pulse generator. At the end of the generated pulse, sample the level of the composite synchronizing signal and output the sampled value. A signal which is switched between a pulse generated by the first pulse generator and a pulse generated by the second pulse generator in accordance with a change in the output signal level of the sampler to be a generated pulse input to the sampler. A synchronization signal separation device comprising a switch.