KR960006531B1 - Character display apparatus of image signal treating system - Google Patents

Abstract

The appartus comprises a first switching unit for selecting a VTR image signal or a camera image signal according to a VTR mode or a camera mode; a second switching unit for selecting the image signal according to the record or regeneration mode; a sixth switching unit for selecting the image signal; a third switching unit for selecting the vertical synchronous signal; a fourth switching unit for selecting the horizontal synchronous signal; and a fifth switching unit for selecting the signal from the AND gate or the signal from the level reducing unit.

Description

Character display device for no signal input of video signal processing system

1 is a block diagram of a video signal processing system according to the present invention.

2 is a diagram illustrating a character mix when a normal video signal or no signal is input in a video signal processing system.

3 is a diagram showing a mix of text signals when no signal is input.

4 shows a mix of pseudo-vertical synchronization signals.

5 is a truth table of each switching unit for selecting a signal according to an input control signal mode.

6 is a truth table of a horizontal synchronous signal and a vertical synchronous signal input to a character generator according to each mode.

* Explanation of cold protection symbols in the main part of the drawing

100,300,1400: Switching unit 1500,2200,2800: Switching unit

400: clamp 500,2000: signal processing system

600: character mixer 70: pseudo-vertical synchronous mixer

800: Y / C mixer 900, 2700: amplifier

1000: noise canceller 1100: character generator

1200: system control unit 1300: synchronous separation unit

1600: synchronization signal generator 1700: AND gate

1900: compound synchronous separator 2300: level attenuator

2400: Inverter 2500: Image signal processor

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a character display apparatus of a video signal processing system, and more particularly, to a video signal processing system capable of displaying a character even when there is no composite synchronization signal, that is, at the time of no signal input.

In the conventional video signal processing system, when no signal is input, such as when there is no complex synchronous signal or noise is reproduced, character display cannot be performed on a screen without a separate signal processing system.

SUMMARY OF THE INVENTION The present invention has been made to solve the conventional problems, and an object thereof is to provide a video signal processing system capable of realizing character display when no signal is input by a separate simple circuit configuration.

In order to achieve the above object, the present invention comprises: first switching means for receiving a VTR video signal or a camera video signal and selecting the signal according to a VTR mode or a camera mode; Second switching means for selecting a video signal in accordance with a recording or reproduction mode; A clamp for setting the signal from the second switching means to the level of the sync tip; A composite synchronization separator for separating and outputting a composite synchronization signal among the image input signals; First signal processing means for processing and outputting a composite synchronous signal from the composite synchronous separating unit, a video signal from the clamp, and a reproduction composite signal (not shown); Character mixer means for mixing a character signal and a character blanking signal from said character generating means and a signal from said clamp; Second signal processing means for receiving and outputting a luminance signal among the signals from the first signal processing means; A system controller which receives a signal from each means and controls the generation of a control signal, image data and pseudo-vertical synchronization signal; Pseudo vertical synchronizing mixer means for mixing the signal from the character mixer means and the pseudo vertical synchronizing signal from the system control means; Amplifying means for amplifying the video signal from the first signal processing means; A video signal processing system comprising a Y / C mixer for mixing a color signal from the first signal processing means and a signal from the pseudo vertical synchronous mixer means to output a video signal, wherein the VTR is recorded according to the recording or reproducing mode of the VTR. Sixth switching means for selecting a video signal from the video signal or the amplifier; Synchronization separation means for separating and outputting the signal applied from the sixth switching means into a vertical synchronization signal and a horizontal synchronization signal; Synchronizing signal generating means for separating and outputting the vertical synchronizing signal, the horizontal synchronizing signal and the composite synchronizing signal in the VCR or camera mode; Inverting means for inverting the composite synchronous signal outputted from the synchronous signal generating means; Level reduction means for attenuating the level of the composite synchronization signal inverted from the inversion means; Signal detection means for receiving the video signal from the sixth switching means and detecting the presence or absence of the video signal; AND gate means for receiving a signal obtained by inverting the control signal CAM (H) / VTR (L) from the system control unit and a signal from the signal detection means and outputting a high or low signal; Third switching means for selecting a vertical synchronous signal from the synchronous separation section or a vertical synchronous signal from the synchronous signal generating means based on the signal of the AND gate means, and the synchronous separation based on the signal of the AND gate means; Fourth switching means for selecting a horizontal synchronizing signal from the negative signal or a horizontal synchronizing signal from the synchronizing signal generating means, and from the signal or level attenuation means from the second signal processing means based on the signal of the AND gate means; It provides a video signal processing system comprising a fifth switching means for selecting a signal of.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 is a configuration diagram of a video signal processing system according to the present invention, in which a line video signal is selected in a VTR mode, but a first switching method of selecting a camera video signal (camera luminance signal + text signal + title luminance signal) in a camera mode. A unit 100, a second switching unit 300 for selecting a VTR image input signal and a reproduction luminance signal, a clamp 400 for fixing a portion of an input signal waveform at a synchronous tip level, and a composite synchronous input signal. A composite synchronous separation unit 1900 for outputting a signal, a first signal processing system 500 for processing a composite synchronous signal, an input video signal, a recording and reproducing signal, and a luminance processed by the first signal processing system 500 A second signal processing system 2000 for receiving a signal (a recording luminance signal and a reproduction luminance signal), a character mixer 600 for receiving a video signal and a text signal and mixing characters under control of a text blanking signal; System control 1200 The pseudo-vertical sync mixer 700 in which the pseudo-vertical sync signals are mixed by the control of the vertical sync pulse, and the camera color signal CAM-C or the reproduction color signal PB-C output from the first signal processing system 500. And a Y / C mixer unit 800 for mixing with the output signal from the pseudo-vertical synchronous mixer 700, and a VTR video signal during recording and a playback video signal output from the amplifier 2700 during playback. The sixth switching unit 2800, a synchronous separation unit 1300 for separating and outputting a horizontal synchronous signal and a vertical synchronous signal among the VTR image input signals, and the synchronous separation unit 1300 under the control of the AND gate 1700. The output signal from the synchronization separating unit 1300 according to the output signal from the third switching unit 1400 and the AND gate 1700 for selecting the vertical synchronization signal and the vertical synchronization signal output from the synchronization signal generator 1600. Horizontal output from the horizontal synchronization signal and the synchronization generating unit 1600 The fourth switching unit 1500 for selecting the synchronization signal, the synchronization signal generator 1600 for outputting the horizontal synchronization signal, the vertical synchronization signal, and the composite synchronization signal, and the presence or absence of a signal applied from the sixth switching unit 2800. Accordingly, the signal detection unit 1800 outputs a high signal or a low signal and the second signal processing system 2000 according to the high or low signal output from the AND gate 1700. Or a fifth switching unit 2200 for selecting a signal output from the attenuator 2300, a system control unit 1200, or the like.

According to the present invention configured as described above, the first switching unit 100 receives a VTR image signal and a camera image signal (camera luminance signal CAM-Y + text signal + title luminance signal TITLE-Y). In this case, the VTR image input signal is selected, and in the camera mode, the camera image signal (camera luminance signal + text signal + title luminance signal) is selected and applied to the second switching unit 300.

In the record mode, the second switching unit 300 selects a video signal (VTR video signal or a camera video signal) output from the first switching unit 100 and is in a play back (PB) mode. In this case, the reproduction luminance signal output from the noise removing unit 1000 is selected and applied to the clamp 400.

The clamp 400 is a circuit for fixing the input signal waveform to the sync tip level by executing a syncstip clamp, and the signal selected from the second switch 300 (the first switch 100 in the recording mode). The video signal or the playback luminance signal of the noise canceling unit 1000 in the playback mode) and then synchronously clamp the signal of the synchronously clamped level to the first signal processing system 500, the character mixer 600, and It is applied to the composite synchronous separator (1900).

The first signal processing system 500 receives not only the image signal applied from the clamp 400 and the composite synchronous signal received from the composite synchronous separator 1900, but also a recording and reproduction signal (not shown), and a color signal and a luminance signal. Separate it and treat it. The luminance signal (recording luminance signal REC-Y or reproduction luminance signal PB-Y) processed by the first signal processing system 500 is input to the second signal processing system 2000, and the first signal processing system The color signal (camera color signal CAM-C or reproduction color signal PB-C) processed at 500 is applied to the Y / C mixer 800.

Meanwhile, the text mixer 600 receiving the video signal output from the clamp 400 mixes the text signal and the text blanking signal output from the text generator 1100 and then mixes the mixed video signal (video signal + text). Signal) is applied to the quasi-vertical synchronous mixer 700.

The quasi-vertical synchronous mixer 700 is generated by the control of the system controller 1200 in order to prevent the image (video signal + text signal) output from the character mixer 600 and the vertical shaking of the screen during the special playback of the VTR. The similar pseudo-synchronous signal is mixed (see FIG. 4) and applied to the Y / C mixer 800. FIG.

The Y / C mixer 800 receives a color signal (reproducing color signal PB-C or camera color signal CAM-C) output from the first signal processing system 500 from the pseudo-vertical synchronous mixer 700. It mixes with the output signal, and the mixed video signal is amplified by the amplifier 900 and output.

The internal control signal of the video signal processor 2500 is decoded by a decoder 2900 to which video serial data is applied under the control of the system controller 1200.

However, the above-described operation of the present invention for realizing the character display cannot be performed by the video signal processor 2500 as described above.

First, the synchronization signal generator 1600 separates the composite synchronization signal, the horizontal synchronization signal, and the vertical synchronization signal and applies them to the inverter 2400, the fourth switching unit 1500, and the third switching unit l400, respectively.

As shown in FIG. 6, the horizontal synchronizing signal and the vertical synchronizing signal input to the character generator 1100 vary depending on the non-signal input among the VTR recording mode, the VTR reproduction mode, and the camera mode.

In the VTR recording mode, a horizontal synchronous signal and a vertical synchronous signal input to the character generator 1100 will be described below. First, in the VTR recording mode, the sixth switching unit 2800 selects a VTR image signal and applies it to the synchronization separating unit 1300 and the signal detecting unit 1800. The sync separator 1300 separates the vertical sync signal and the horizontal sync signal from the VTR image signals output from the sixth switch 2800 and is applied to the third switch 1400 and the fourth switch 1500.

The third switching unit 1400 and the fourth switching unit 1500 receive the synchronous signal output from the synchronous separation unit 1300 and the synchronous signal output from the synchronous signal generator 1600, and then the AND gate 1700 of the AND gate 1700. The output vertical synchronization signal and the horizontal synchronization signal of the synchronization separator 1300 are selected according to the control signal. That is, when the output of the AND gate 1700 is high, the third switching unit 1400 and the fourth switching unit 1500 select the vertical synchronization signal and the horizontal synchronization signal output from the synchronization separation unit l300. Although applied to the character generator 1100, when the output of the AND gate 1700 is low, the third switching unit 1400 and the fourth switching unit 1500 are vertical synchronous outputs from the synchronization signal generator 1600. The signal and the horizontal synchronous signal are respectively selected and applied to the character generator 1100.

In the VTR reproducing mode, the horizontal synchronizing signal and the vertical synchronizing signal inputted to the character generator 1100 will be described. First, in the VTR reproducing mode, the sixth switching unit 2800 selects a reproduced video signal output through the amplifier 2700 and applies it to the synchronization separating unit 1300. The sync separator 1300 separates the vertical sync signal and the horizontal sync signal from the reproduced video signals output from the sixth switch 2800 and applies them to the third switch 1400 and the fourth switch 1500, respectively. As described above, the third switching unit 1400 and the fourth switching unit 1500 output the vertical synchronizing signal and the horizontal synchronizing signal (synchronizing separation unit 1300) of the reproduced video signal according to the control signal of the AND gate 1700. Signal).

That is, when the output of the AND gate 1700 is high, the third switching unit 1400 and the fourth switching unit 1500 select the vertical synchronization signal and the horizontal synchronization signal output from the synchronization separation unit 1300. When the output of the AND gate 1700 is low, the third switch 1400 and the fourth switch 1400 and the fourth switch 1500 are synchronized signals. The vertical synchronous signal and the horizontal synchronous signal output from the generator 1600 are respectively selected and applied to the character generator 1100.

In the camera mode, the horizontal synchronous signal and the vertical synchronous signal input to the character generator 1100 will be described. First, in the camera mode, the third switching unit 1400 selects the vertical synchronization signal output from the synchronization signal generator 1600 and applies it to the character generator 1100, and the fourth switching unit 1500 is the synchronization signal generator. The horizontal synchronous signal output from the 1600 is selected and applied to the character generator 1100.

On the other hand, when no signal is input in the recording or reproducing mode of the VTR, character display cannot be performed (see FIG. 2), and the character is displayed in the following configuration.

The sixth switching unit 2800 that receives the VTR video signal or the reproduced video signal output from the amplifier 2700 selects the VTR video signal and applies it to the signal detector 1800 and the sync separator 1300 during recording. During playback, the playback video signal is selected and applied to the signal detector 1800 and the sync separator 1300.

The signal detector 1800 detects the presence or absence of a signal output from the sixth switch 2800. If there is a signal output from the sixth switching unit 2800, the signal detector 1800 outputs a high signal (signal name: synchronous detection signal H) and a low signal (synchronous detection signal L) if there is no signal. ) Is applied to the system controller 1200 and the AND gate 1700.

The AND gate 1700 is connected to a camera / VTR video signal (CAM (L) / VTR (H) and a camera / VTR video signal (CAM (H) / VTR (L)) output from the system controller 1200. The synchronous detection signal H output from the detector 1800 is input, and when the AND gate 1700 receives the normal video signal in the VTR recording or reproducing mode, a high signal is output. To the third switching unit 1400, the fourth switching unit 1400, and the fifth switching unit 2200. However, when no signal is input in the recording or reproducing mode of the VTR, or in the camera mode. The low signal is output and applied to the third switching unit 1400, the fourth switching unit 1500, and the fifth switching unit 2200.

The operation of the third switch unit 1400 and the fourth switch unit 1500 is the same as described above, and the fifth switch unit 2200 performs the second signal processing system 2000 according to the control signal of the AND gate 1700. Signal from the level attenuator 2300 is selected. Therefore, when the signal output from the AND gate 1700 is high, the fifth switching unit 2200 selects the signal output from the second signal processing system 2000 and outputs the signal from the AND gate 1700. If the received signal is low, the analog image signal formed by inverting the composite synchronous signal output from the synchronization signal generator 1600 by the inverter 2400 and then attenuating the level by the level attenuator 2300 (composite) Sync signal) is applied to the noise canceller 1000.

On the other hand, the system controller 1200 receiving the synchronization detection signal from the synchronization detection unit 1800 recognizes that the signal is no signal when the synchronization detection signal is low, and switches the switch of the second switching unit 300 to video serial data. By connecting to a play back (PB) terminal, a similar image signal is applied to the character mixer 600 so that the character signal is mixed (see FIG. 3). However, when the sync detection signal output from the sync detector 1800 is high, the system controller 1200 performs a normal operation.

As described above, the present invention enables character display during no signal input.

Claims (1)

First switching means (100) for receiving the VTR video signal or the camera video signal and selecting the signal according to the VTR mode or the camera mode; Second switching means (300) for selecting a video signal in accordance with a recording or reproduction mode; A clamp 400 for setting the signal from the second switching means 300 to the level of the sync tip; A composite synchronization separator 1900 for separating and outputting a composite synchronization signal among the image input signals; First signal processing means (500) for processing and outputting a composite synchronization signal from the composite synchronization separator (1900), an image signal from the clamp (400), and a reproduction composite signal; Character mixer means (600) for mixing the character signal and the character blanking signal from the character generating means (1100) with the signal from the clamp (400); Second signal processing means (2000) for receiving and outputting a luminance signal among the signals from the first signal processing means (500); A system controller 1200 which receives a signal from each means and controls generation of a control signal, video serial data, and pseudo vertical synchronization signal; Pseudo-vertical sync mixer (700) for mixing the signal from the character mixer means (600) and the pseudo-vertical sync signal from the system control means (1200); Amplifying means (2700) for amplifying the video signal from the first signal processing means (500); In the video signal processing system comprising a Y / C mixer 800 for mixing the signal from the pseudo vertical synchronizing mixer 700 from the first signal processing means 500 to output a video signal. A sixth switching means 2800 for selecting a video signal from the VTR video signal or the amplifier 2700 according to the recording or reproducing mode of the apparatus; Synchronization separation means (1300) for separating and outputting the signal applied from the sixth switching means (2800) into a vertical synchronization signal and a horizontal synchronization signal; Synchronization signal generating means 1600 for generating a vertical synchronization signal, a horizontal synchronization signal, and a composite synchronization signal in the VCR or camera mode; Inverting means 2400 for inverting the composite synchronous signal output from the synchronous signal generating means 1600; Level attenuating means (2300) for attenuating the level of the composite synchronization signal inverted from the inverting means (400); Signal detection means (1800) for receiving the video signal from the sixth switching means (2800) and detecting the presence or absence of the video signal; A signal obtained by inverting the control signal CAM (H) / VTR (L) from the system control unit 1200 and a signal from the signal detection unit 1800 is applied to receive a high or low signal. AND gate means 1700 for outputting; Third switching means (1400) for selecting a vertical synchronous signal from the synchronous separation unit (1300) or a vertical synchronous signal from the synchronous signal generating means (600) based on the signal of the AND gate means (1700); Fourth switching means 1500 for selecting a horizontal synchronous signal from the synchronous separation unit 1300 or a horizontal synchronous signal from the synchronous signal generating means 1600 based on the signal of the AND gate means 1700; And fifth switching means 2200 for selecting a signal from the second signal processing end 2000 or a signal from the level attenuation means 2300 based on the signal of the AND gate means 1700. Character display device for no signal input of video signal processing system.