JPH04189087A - High definition television receiver - Google Patents

Abstract

PURPOSE:To display a video signal without disturbance even when no synchronizing signal exists by providing a circuit selecting a synchronizing signal detection circuit and a video signal generating circuit and switching the circuits automatically. CONSTITUTION:A changeover circuit 9 switches the output of a video amplifier circuit 3 or the output of a video signal generating circuit 8 based on the output of a synchronizing signal detection circuit 7 and sends the result to a high definition display device 6. The circuit 7 detects the presence of a synchronizing signal and when no synchronizing signal exists, the synchronizing signal generated from a deflection circuit 5 is inputted to the circuit 8, its output is switched by the circuit 9 and a video image is displayed. In this case, the deflection circuit 5 uses a horizontal synchronizing signal and a vertical synchronizing signal outputted from a synchronization processing circuit 4 to take synchronization for horizontal and vertical deflection and generates a synchronizing signal. Thus, even in the absence of the synchronizing signal, the synchronizing signal generated from the circuit 5 is used to display a video image.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a high-definition television receiver.

Conventional technology High-definition television (hi-vision) aims to display detailed television images on a large wide screen to provide new appeal, such as the power and sense of place that cannot be obtained with current television broadcasting. In recent years, interest has been increasing in all countries. This high-definition television has 11,125 scanning lines and an aspect ratio of 16:9, whereas the current standard television system has 525 scanning lines and an aspect ratio of 4:3. However, high-definition television will not suddenly replace the current standard television, and it is thought that both television systems will coexist. At this time, high-definition television reception bag! However, it is necessary to receive and play back images from current standard televisions.

An example of the above-mentioned conventional high-definition television receiving device will be described below with reference to the drawings.

FIG. 3 is a block diagram showing the configuration of a conventional high-definition television receiver. In FIG. 3, 1 is a high-definition video input terminal for inputting a high-definition video signal (G, B, R or Y, Pb, Pr), 2 is a high-definition synchronization input terminal for inputting a high-definition synchronization signal (HD, VD), and 3 is a video amplification circuit that amplifies the aforementioned high-definition video signal, 4 is a synchronization circuit that performs synchronization processing, 5 is a horizontal
A deflection circuit that performs vertical deflection; 6 is the aforementioned video amplification circuit 3;
It is a high-quality display with a 16:9 aspect ratio that displays the output of

The operation of the high-definition television receiving apparatus configured as described above will be explained below.

A high-definition video signal (G, B, R or Y, Pb, Pr) is input from a high-definition video input terminal 1 .

Furthermore, a high-definition synchronization signal (HD, VD) is input from the high-definition synchronization input terminal 2 . The synchronization processing circuit 4 receives a synchronization signal from the input terminal 2 and a video signal from the video amplification circuit 3, and if the synchronization signal is added to the video signal, performs synchronization shunting from the video signal.
The horizontal signal (HD) and vertical signal (VD) are sent to the video amplification circuit 3.
, is output to the deflection circuit 5. The video amplification circuit 3 clamps the aforementioned high-definition video signals (G, B, R) with a horizontal signal, adjusts contrast and brightness, and then amplifies and outputs the signal. The deflection circuit 5 calculates horizontal deflection and vertical deflection from the horizontal and vertical signals output from the synchronization processing circuit 4, respectively.
The vertical deflection is synchronized and the output of the video amplification circuit 3 described above is displayed on a high-quality display 6.

Problem to be Solved by the Invention However, with the above configuration, if there is no video signal (No. 3, synchronization signal), no video is displayed. , I don't know if it's because the high-definition receiver is malfunctioning.

Further, there is a problem in that, although the video signal is normal, if there is no synchronization signal or the level of the synchronization signal is irregular, a distorted video will be displayed.

The present invention outputs a video signal even when there is no synchronization signal, and prevents no video from being displayed or a distorted video from being displayed.

Means for Solving the Problems - In order to solve the problem described in J.2, the present invention provides a synchronization signal detection circuit, a video signal generation circuit that outputs a specific video signal, and a switching circuit, so that when there is no synchronization signal, In this case, the device is configured to generate a specific video signal.

Effect of the present invention With the above-described configuration, the synchronization signal detection circuit detects the presence or absence of a synchronization signal, and if there is no synchronization signal, inputs the synchronization signal generated from the deflection circuit to the video signal generation circuit,
A switching circuit switches the output of the video signal generation circuit to display the video.

Embodiment Hereinafter, a high-definition television receiving apparatus according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of a high-definition television receiver according to an embodiment of the present invention, and FIG. 2 is an explanatory diagram of the operation of a synchronization signal detection circuit.

In FIG. 1, 1 is a high-definition video signal (G.

2 is a high-definition video input terminal for inputting B, R or Y, , Pb, Pr), and 2 is a high-definition synchronizing signal (HD,
3 is a video amplification circuit that amplifies the above-mentioned high-definition video signal, 4 is a synchronization processing circuit that performs synchronization processing, 5 is a deflection circuit that performs horizontal and vertical deflection, and 6 is the above-mentioned deflection circuit. 7 is a synchronization signal detection circuit that detects the presence or absence of a synchronization signal; 8 is a video signal generation circuit that generates a specific video signal; 9 is a switching circuit that switches between the output of the video amplification circuit 3 and the output of the video signal generation circuit 8 based on the output of the synchronization signal detection circuit 7.

The operation of the high-definition television receiving apparatus configured as described in Section 2 will be described below with reference to FIGS. 1 and 2. A high-definition video signal (G, B, R or Y, Pb, Pr) is input from a high-definition video input terminal 1 . Furthermore, a high-definition synchronization signal (HD, VD) is inputted from the high-vision synchronization input terminal 2. In the synchronization processing circuit 4, a synchronization signal is inputted from the input terminal 2 described above, and a video signal is inputted from the image amplification circuit 3. If a synchronization signal is added to the video signal, the synchronization signal is separated from the video signal, and a horizontal signal (DAD) and a vertical signal (VD) are output to the video amplification circuit 3, deflection circuit 5, and synchronization signal detection circuit 7. The video amplification circuit 3 receives the input high-definition video signal (
G, B, R) with a horizontal signal (HD),
After adjusting contrast and brightness, amplify and output.

The synchronization signal detection circuit 7 receives a synchronization signal (for example, a horizontal signal) that is the output of the synchronization processing circuit 4 described above.

The synchronization signal detection circuit 7 is constructed of a retriggerable mono-multi-by-break circuit as shown in FIG. 2(a). As shown in FIG. 2(b), a synchronization signal (for example, a horizontal signal) which is the output of the synchronization processing circuit 4 described above is input to this mono-multivibrator. In the retriggerable mono multi-bi break, the width of the output signal, the retriggerable signal, is IOH (10
The values of the resistors and capacitors are determined so that the horizontal period) is achieved. Therefore, as shown in FIG. 2(C), from the falling edge of the negative pulse of the input signal, a positive pulse between ]ohu is output,
If the negative pulse (J(D)) of the input signal is not continuous during the IOH period, a negative pulse is output. The deflection is synchronized and a deflection signal is output, but if there is no horizontal signal, vertical signal, or both, a free-running horizontal signal, vertical signal, and deflection signal are output from the internal oscillation circuit. 1! ItV image signal generation In the circuit 8, a specific video signal is generated by synchronizing with the horizontal signal and vertical signal which are the outputs of the deflection circuit 5 described above.In the switching circuit 9, the detection signal which is the output of the synchronization signal detection circuit 7 described above is set to Hi. If the detection signal is low (there is a synchronization signal), the output of the video amplification circuit 3 described above is selected, and if the detection signal is Low (there is no synchronization signal), the output of the video signal generation circuit 8 described above is selected.High quality display 6 displays the output of the switching circuit 9 mentioned above.

As described above, according to this embodiment, the synchronization signal detection circuit 7
A video signal generation circuit 8 and a switching circuit 9 are provided, and when there is no synchronization signal, a specific video signal output from the video signal generation circuit 8 is displayed, so that no video is displayed or a distorted video is displayed. can be prevented from being displayed.

Effects of the Invention As described above, according to the present invention, by providing a synchronization signal detection circuit, a video signal generation circuit, and a switching circuit, even when there is no synchronization signal, the signal can be automatically switched and a specific video signal can be increased. It can be displayed on the quality display 6.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of a high-definition television receiver according to an embodiment of the present invention, and FIG.
b) and (C) are a circuit diagram and a waveform diagram for explaining the operation of the period detection circuit, and FIG. 3 is a block diagram showing the configuration of a conventional high-definition television receiver. 1...High-definition video input terminal, 2...
...High-definition synchronization input terminal, 3...Video amplification circuit, 4...Synchronization processing circuit, 5...
Deflection circuit, 6...High quality display, 7...
... Synchronization signal detection circuit, 8 ... Video signal generation circuit, 9 ... Switching circuit.

Claims (1)

[Claims] A video signal amplification circuit that inputs a high-definition television system signal and amplifies the video signal; a synchronization processing circuit that inputs the high-definition television system signal and performs synchronous separation; and a synchronization processing circuit that inputs a synchronization signal and performs deflection. A deflection circuit that generates a signal, a video signal generation circuit that generates a specific video signal, a synchronization signal detection circuit that detects the presence or absence of a synchronization signal output from the synchronization processing circuit, and the output of the video signal amplification circuit described above. It is equipped with a switching circuit that switches between the signal and the output signal of the video signal generation circuit described above, and when there is no synchronization signal, a specific video signal is displayed on a high-quality display using the detection signal that is the output of the synchronization signal detection circuit. High-definition television receiver.