JPH07231410A - Television receiver - Google Patents

Abstract

PURPOSE:To prevent the on-screen character information, etc., from being impaired by detecting the synchronization of a video signal and video quality, judging the propriety of the use of the synchronization and switching external/ internal synchronizations. CONSTITUTION:An external synchronization detection means 5 detects the presence or absence of the synchronization signal of an inputted video signal, a video quality detection means 6 detects video quality and a judgment means 7 judges the propriety of the use of the synchronizing signal of the video signal. Command signals are given to use the synchronizing signal of the inputted video signal when a high quality synchronizing signal is detected and to use an internal synchronizing signal even if the synchronizing signal is detected when a low quality signal including noise component of more than that the reference is detected. An on-screen circuit part 2 inputs a video signal from a tuner 1, superimposes the character signal inputted by an input means 9 on the external/internal video signal switched by synchronizing with the synchronizing signal where the outside/inside are switched by the command of a synchronizing signal switch means 8 and displays the signal on a monitor part 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a television receiver or the like, and more particularly to internal / external synchronous switching control in an on-screen circuit for displaying a selected channel number or the like on the screen.

[0002]

2. Description of the Related Art As shown in FIG. 4, an internal / external synchronization switching control in an on-screen circuit of a conventional television receiver is performed by a video input section for inputting a video signal and a synchronization signal from the input video signal. A sync separation circuit section for separating the sync signal, a sync signal generating section for generating a sync signal, a sync switching control input section for inputting a sync switching control signal, and an internal sync signal from the sync signal generating section by the sync switching control signal. And a synchronization switching means for switching the external synchronization signal from the synchronization separation circuit section, a character generating means for generating a character signal in synchronization with the switching synchronization signal, and a control for controlling the character generating means, the synchronization switching means, etc. Means, superimposing means for superimposing a character signal generated by the character generating means on a video signal input from the video input section, and the superimposing means. In an on-screen circuit section configured by output means for outputting a pause signal, a detection signal obtained by detecting the presence / absence of an external synchronization signal by the synchronization detection means is input to the synchronization switching control input section as a synchronization switching control signal and turned on. The internal / external synchronization of the screen circuit is switched, and when there is no external synchronization signal, the internal synchronization signal from the synchronization signal generator is used. However, in such internal / external synchronization switching control in the on-screen circuit section, if there is a sync signal even if the signal is of a quality such that the video signal is deteriorated and noise is superimposed on the sync signal to disturb synchronization. Since the synchronization of video signals is used, information such as characters to be on-screen may be distorted and displayed on the monitor screen, making it difficult to see.

[0003]

In order to solve such a problem, the present invention detects the presence or absence of a synchronizing signal of an input video signal and the video quality, so that a noise component above a reference level is superimposed. In case of a poor quality signal, even if a sync signal is detected, the internal sync from the sync signal generator is used to display information such as characters as a video signal on the monitor.
An object is to provide a television receiver in which information such as characters can be viewed without being disturbed.

[0004]

In order to solve the above problems, the present invention provides a video input section for inputting a video signal from a tuner or the like, and a sync separation circuit section for separating a sync signal from the input video signal. A sync signal generating section for generating a sync signal, a sync switching control input section for inputting a sync switching control signal, an internal sync signal from the sync signal generating section based on the sync switching control signal, and a sync separation circuit section. A synchronization switching means for switching the external synchronization signal, a character generation means for generating a character signal in synchronization with the switching synchronization signal, and a character signal generated by the character generation means for the video signal input from the video input section. An on-screen circuit section comprising superimposing means for superimposing and output means for inputting the superimposing signal to the monitor section; Character generator means of the screen circuit section,
Control means for controlling the synchronization switching means, external synchronization detection means for detecting the presence or absence of the synchronization signal of the video signal input from the tuner, video quality detection means for detecting the video quality of the video signal, and the detection And a synchronization switching control signal generating means for determining whether or not the external synchronization signal of the video signal can be used based on the external synchronization detection signal and the video quality detection signal. The synchronous switching control signal to be output is input to the synchronous switching control input section.

[0005]

With the above construction, in the television receiver according to the present invention, the image quality detecting means detects the image quality and determines the presence or absence of the synchronizing signal of the video signal input to the synchronization detecting means. Determines whether or not to use the sync signal of the video signal, and switches the internal / external sync of the on-screen circuit. When a good-quality sync signal is detected, the sync signal of the input video signal is detected. When a poor quality signal such as a noise component above the reference is used, the internal sync signal from the external sync signal generator is used to detect characters such as characters even if the sync signal is detected. Information is displayed on the screen as a video signal.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of a television receiver according to the present invention will be described in detail below with reference to the drawings. 1 is a block diagram of essential parts showing an embodiment of a television image receiving apparatus according to the present invention, FIG. 2 is a detailed block diagram of an on-screen circuit unit shown in FIG. 1, and FIG. 3 is a detail of image quality detecting means shown in FIG. A block diagram is shown. In the figure, 1 is TV, C
A tuner for receiving broadcasts such as S and BS demodulates and outputs video signals and the like. Reference numeral 2 is an on-screen circuit unit for inputting the video signal, adding information such as characters and outputting it.
As shown in FIG. 2, a video input unit 21 for inputting a video signal.
A sync separation circuit section 22 for separating a sync signal from the input video signal, a sync signal generation section 23a for generating a sync signal, and a video signal generation section 23 for generating an internal video signal.
b, a sync switching control input section 24 for inputting a sync switching control signal, and a sync switching for switching between an internal sync signal from the sync signal generating section and an external sync signal from the sync separation circuit section by the sync switching control signal. Means 25a, and a video switching means 25b for switching the internal video signal and the video signal input to the video input section 21 by the synchronous switching control signal,
A character generating means 26 for generating and storing a character signal in synchronization with the switching synchronizing signal, and a control input section 2 for inputting control signals to the character generating means 26, the synchronization switching means 25 and the like.
7, superimposing means 28 for superimposing a character signal generated by the character generating means 26 on the video signal input from the video input section 21, and an output section 29 for outputting the superimposing signal. I am configuring. Reference numeral 3 is a monitor unit for inputting an image signal from the on-screen circuit unit and displaying it on the screen. 4 is a control means,
The character generation means 26, the synchronization switching means 25, etc. are controlled via the control input means 27 of the on-screen circuit section 2. Reference numeral 5 denotes an external sync detecting means for detecting the presence or absence of a sync signal of the video signal input from the tuner or the like. Reference numeral 6 denotes a video quality detecting means for detecting the video quality of a video signal input from the tuner or the like, and as shown in FIG. 3, a bandpass filter 61 having a center frequency of about 9 MHz, a reference voltage generating section 62, and a voltage. It is composed of a comparison unit 63. 7
Is a judging means which uses the external synchronizing signal or the internal synchronizing signal based on the presence / absence information of the external synchronizing signal from the external synchronizing detecting means 5 and the image quality information from the image quality detecting means 6. The synchronous switching control signal is input to the synchronous switching control input section 24 of the on-screen circuit section 2. Reference numeral 8 is a synchronization switching control signal generating means, which is composed of the external synchronization detecting means 5, the image quality detecting means 6, and the judging means 7. Reference numeral 9 denotes input means such as a keyboard. Information such as characters input from the input means is input to a memory 26a provided in the character generation means 26 of the on-screen circuit unit 2.

The operation of the above arrangement will be described below. A video signal such as a TV broadcast received and demodulated by the tuner 1 is input to the on-screen circuit unit 2 and the synchronization switching control signal generating means 8. The sync detecting means 5 of the sync switching control signal generating means 8 inputs the presence / absence of the sync signal of the video signal, and the video quality detecting means 6 inputs the demodulated signal to the bandpass filter section 61, and the white noise around 9 MHz is inputted. The component is selectively amplified and input to the voltage comparison means 63, and compared with the voltage generated by the reference voltage generation means 62,
If the white noise that is selectively amplified is smaller than the reference voltage, the quality is detected as good, and if it is large, the quality of the image is detected as poor, and the judging means 7 judges whether or not the sync signal can be used based on the both detection signals. Judgment is made and the synchronization switching control signal is input to the synchronization switching control input section 24 of the on-screen circuit section 2. Also, the on-screen circuit unit 2
On the one hand, the video signal input to the video input section 21 is separated by the sync separation circuit section 22, the sync signal is input to the synchronization switching means 25a, and the other video signal is input to the video switching means 25b. Is entered. The sync signal generated by the sync signal generating section 23a of the on-screen circuit 2 is input to the sync switching means 25a, and the internal video signal generated by the video signal generating means 23b is input to the video switching means 25b. If the input video signal has a synchronization signal and the quality of the video signal is good according to the synchronization switching control signal input to the unit 24, the external synchronization signal and the external video signal are switched to synchronize the input video signal. If there is no signal, or if there is a sync signal and the image signal quality is poor,
The output is switched to internal sync and internal video signals.
The switched synchronizing signal and video signal are input to the character generation means 26 and the superimposing means 28, and information such as characters is synthesized with the switched video signal,
It is input to the monitor unit from the output unit 29 and displayed on the screen. Further, it is possible to input necessary character information from the input means 8 and store it in the storage section of the character generating means 26 to use it as information such as characters.

[0008]

As described above, according to the internal / external synchronization switching control method / apparatus of the present invention, the synchronization of the video signal depending on the presence / absence of synchronization of the video signal input from the tuner and the quality of the video signal. Information such as characters is disturbed because the signal is separated and it is determined whether to use the video signal and sync signal or to use the internal sync signal and internal video signal generated inside the on-screen circuit unit. No video signal is output and displayed on the monitor screen.

[Brief description of drawings]

FIG. 1 is a block diagram of essential parts showing an embodiment of a television receiver according to the present invention.

FIG. 2 is a detailed block diagram of an on-screen circuit unit showing an embodiment of a television receiver according to the present invention.

FIG. 3 is a detailed block diagram of image quality detecting means showing an embodiment of a television image receiving apparatus according to the present invention.

FIG. 4 is a principal block diagram showing a conventional television image receiving device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 tuner 2 on-screen circuit section 3 monitor section 4 control means 5 external synchronization detection means 6 video quality detection means 7 judgment means 8 sync switching control signal generation means 9 input means 21 video input section 22 sync separation circuit section 23a sync signal generation section 23b video signal generating unit 24 synchronous switching control input unit 25a synchronous switching unit 25b video switching unit 26 character generating unit 27 control input unit 28 superimposing unit 29 output unit 61 band pass filter unit 62 reference voltage generating unit 63 voltage comparing unit 63

Claims (5)

[Claims] 1. A video input section for inputting a video signal from a tuner or the like, a sync separation circuit section for separating a sync signal from the input video signal, a sync signal generating section for generating a sync signal, and a synchronization switching control. A synchronization switching control input unit for inputting a signal, a synchronization switching unit for switching between the internal synchronization signal from the synchronization signal generating unit and the external synchronization signal from the synchronization separation circuit unit by the synchronization switching control signal, and the synchronization signal to be switched. And a superimposing means for superimposing a character signal generated by the character generating means on the video signal input from the video input section, and a signal for superimposing the character signal. An on-screen circuit section configured by an output means for inputting to the monitor section, and a character generating means of the on-screen circuit section,
Control means for controlling the synchronization switching means, external synchronization detection means for detecting the presence or absence of the synchronization signal of the video signal input from the tuner, video quality detection means for detecting the video quality of the video signal, and the detection And a synchronization switching control signal generating means for determining whether or not the external synchronization signal of the video signal can be used based on the external synchronization detection signal and the video quality detection signal. A television receiver characterized in that a synchronous switching control signal to be outputted further is inputted to the synchronous switching control input section. 2. The on-screen circuit section is provided with an internal video signal generating means, and an external video signal and an internal video signal from the internal video signal generating means are generated by a synchronous switching control signal input to the synchronous switching control input section. The television receiver according to claim 1, further comprising switching means for switching. 3. The on-screen circuit section is provided with an input means, and information such as characters is inputted and stored in the memory of the character generation means by the input means.
The television receiver described. 4. The image quality detecting means comprises a bandpass filter, a reference voltage generating means, and a comparing means,
When the output signal level of the bandpass filter is higher than the reference signal, the image quality deterioration signal is output from the comparing means, and when the output signal level of the bandpass filter is lower than the reference signal, the image quality good signal is output from the comparing means. 4. The television receiver according to claim 1, claim 2, or claim 3. 5. The television receiver according to claim 1, wherein the bandpass filter has a center frequency of approximately 9 MHz.