JPH02312379A - Hdtv signal discrimination switching circuit - Google Patents

Abstract

PURPOSE:To obtain an appropriate video corresponding to the kind of a signal by automatically switching a phase or picture width by automatically discriminating the kind of an HDTV signal. CONSTITUTION:The circuit is comprised of a signal discrimination circuit 1 to discriminate a baseband signal from a MUSE signal, a horizontal picture phase switching circuit 2 to switch the phase and width of a horizontal picture, respectively setting the discrimination output of the discrimination circuit 1 as input, and a horizontal picture width switching circuit 3. And the phase and the width of the horizontal picture can be automatically switched so as to set the signal at the one corresponding to the kind of the HDTV signal by discriminating the baseband signal from the MUSE signal. In such a way, it is possible to save time and labor for manual adjustment, and to obtain the video with appropriate picture phase and picture width corresponding to the kind of the signal.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention is directed to HDT used in high-definition receivers,
The present invention relates to a V signal discrimination switching circuit that can automatically discriminate between two types of HDTV signals and automatically switch the phase and width of a horizontal screen depending on the type.

(Prior art) There are two types of transmission formats for high-definition signals: baseband signals and MUSE signals.The MUSE signal compresses a baseband signal with a band of 30MHz to 8.IMHz and can be transmitted in a band equivalent to one satellite channel. The high-definition receiver usually uses this MUS.
Although it only receives B signals, television cameras and
It is also possible to receive a baseband signal from a TR or the like as an external input.

By the way, as shown in Fig. 3, the baseband signal and ML
The ISB signal differs in phase and width (time) based on the horizontal synchronization signal of the image information, so conventionally, the horizontal position and width of the screen were adjusted according to the type of signal, and the baseband signal Switching of the phase and horizontal width of the image by automatic discrimination between the signal and the MUSE signal was not particularly performed.

[Problem to be solved by the invention]

In this way, automatic discrimination between the baseband signal and the MUSE signal has not been performed in the past, and if adjustments are made for either signal, the horizontal position of the screen will change when the other signal is input. , screen width, etc. are misaligned, and the 4th
As shown in the figure, there were problems such as the screen position shifting and the horizontal width being cut off.

This invention was made in order to solve the problems of the conventional ones as mentioned above.
It is an object of the present invention to provide an HDTV signal discrimination switching circuit that can automatically discriminate between signals and switch the horizontal position, screen width, etc. to appropriate ones for either signal input.

[Means to solve the problem]

The HDTV signal discrimination switching circuit according to the present invention is based on the MUSE
It is provided with a discrimination circuit that discriminates between a signal and a baseband signal, and a horizontal screen phase switching circuit and a horizontal width switching circuit that receive the output of the discrimination circuit as input.

[Effect]

In this invention, by distinguishing between the baseband signal and the MUSE signal, the phase and width of the horizontal screen are automatically switched to match the type of HDTV signal. Appropriate images can be obtained depending on the type.

〔Example〕

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

FIG. 1 is an overall configuration diagram of an HDTV signal discrimination switching circuit according to an embodiment of the present invention. In FIG. 1, 1 is a signal discrimination circuit that discriminates between a baseband signal and a MUSE signal, and 2 and 3 are horizontal screen phase switching circuits that use the discrimination output of discrimination circuit 1 as input to switch the horizontal screen phase and horizontal screen width, respectively. circuit and horizontal screen width switching circuit.

FIG. 2 is a block diagram showing the discrimination method of the signal discrimination circuit. In FIG. 2, 4 is an input circuit, 5.6 is a timing pulse generator, 7 is an AND circuit, 8 is an output circuit,
9.10 is an output terminal of the input circuit 4.

Next, the operation of the above embodiment will be explained with reference to FIG. FIG. 3 is a timing chart of the MUSE signal (see (a) in the figure) and the baseband signal (see (b) in the figure).

First, when a video signal is input, the synchronization signal is used as a reference.
Pulses are generated from the timing pulse generator 5 after T and after T2 from the timing pulse generator 6, and are input to the input circuit 4. The input circuit 4 takes in the video signal in response to the generation of the pulse, and outputs from the output terminal 9 the presence or absence of the video signal at 11 o'clock, and from the output terminal 10 T.
The presence or absence of the video signal at time t is output to the AND circuit 7.

As is clear from FIG. 3, since there is a video signal after T+ and Tg only in the case of the baseband signal, the AND circuit 7
When the output is high, it is determined that it is a baseband signal, and when it is low, it is determined that it is a MUSE signal, and the output circuit 8 drives the horizontal screen phase switching circuit 2 and the horizontal screen width switching circuit 3.

The horizontal screen phase switching circuit 2 and the horizontal screen width switching circuit 3 switch the horizontal screen phase and horizontal screen width by respectively switching circuit constants such as resistance values depending on whether or not the output circuit 8 is driven.

In this way, in this embodiment, the baseband signal and MUS
By distinguishing between E and E signals, the phase and width of the horizontal screen are automatically switched to match the type of HDTV signal, eliminating the need for manual adjustment. It is possible to obtain an image of one screen width with an appropriate screen phase.

In the above embodiment, the phase 1 width of the horizontal screen is switched, but the vertical width, raster distortion, convergence, etc. may also be switched.

Furthermore, although the above embodiments have been described as being used in high-definition receivers, they may also be used in high-definition VTRs, etc., and the same effects as in the above embodiments can be achieved.

〔Effect of the invention〕

As described above, according to the I (DTV signal discrimination switching circuit) according to the present invention, the phase and screen width are automatically switched by automatically discriminating the type of HDTV signal. This has the effect of obtaining an appropriate phase and screen width depending on the situation.

[Brief explanation of drawings]

FIG. 1 is an overall configuration diagram of an HDTV signal discrimination switching circuit according to an embodiment of the present invention, FIG. 2 is a block diagram showing a discrimination method of the signal discrimination circuit, and FIG. 3 is a timing diagram of a baseband signal and a MUSE signal. A diagram showing a chart, and FIG. 4 is a diagram showing a screen when a MUSE signal is input after adjustment is performed using a baseband signal. In the figure, 1 is a signal discrimination circuit, 2 is a horizontal screen phase switching circuit, 3 is a horizontal screen width switching circuit, 4 is an input circuit in the signal discrimination circuit, 5.6 is a timing pulse generation circuit, and 7 is an A
ND circuit, 8 is an output circuit, and 9.10 is an output terminal of the output circuit. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] (1) Baseband signal which is HDTV signal and MUSE
An HDTV signal discrimination switch comprising: a discrimination circuit for discriminating signals; and a horizontal screen phase switching circuit and a horizontal width switching circuit for switching a horizontal screen phase and a horizontal screen width according to a discrimination output of the discrimination circuit. circuit.