JPH0483494A - Converter for converting high-vision signal into ntsc signal - Google Patents

Abstract

PURPOSE:To prevent the generation of a band-like burning on a boundary by outputting a video signal to which a DC of a prescribed level is superimposed to the video signal blank part of a high-vision signal generated due to down- conversion to an NTSC system through a selector. CONSTITUTION:The video signal of a high-vision signal down-converted into the NTSC system and a video blank signal generated from a video blank signal generator 4 are applied to the selector 2 through an input terminal 1. A video signal increasing the brightness of upper and lower blank parts by superimposing a DC to the blank parts is outputted from the selector 2 and supplied to an output terminal as a video output signal. Consequently, the generation of a band-like burning on the boundary between a video signal displaying part and a blank part can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a converter for converting high-definition signals to NTSC signals.

In order to view high-definition signals on current general NTSC signal reproduction TVs, it is necessary to convert the number of scanning lines, and
Since the aspect ratios of screens also differ, it is also necessary to handle differences in aspect ratios.

[Conventional technology]

The aspect ratio of the high-definition signal is 9:16, and the NTS
The aspect ratio of the C signal is 3:4, and in order to handle this difference in aspect ratio, conventionally, the vertical length of the west side of the high-definition signal was projected on the screen of the TV for reproducing the NTSC signal. Either cut off the horizontal length of the high-definition signal screen, compress the horizontal length of the high-definition signal screen, or convert the high-definition signal screen to NT with the same aspect ratio of 9=16.
I was trying to display it on the screen of a TV that plays SC signals.

[Problem to be solved by the invention]

The aspect ratio of the high-definition signal screen is 9:
16 (I semi-mode)') on the screen of a television for reproducing NTSC signals, and assuming that the vertical length of the screen for reproducing NTSC signals is 3, the video signal is 1.5/4. As shown in FIG. 3, blank areas without NTSC signals appear at the top and bottom of the screen of a television set for reproducing NTSC signals.

If you receive images in this state for a long time, the luminescent characteristics of the cathode ray tube's phosphor in the area where the video signal is displayed will change, so the boundary between the area where the video signal is displayed and the blank area will become brighter, causing the NTSC signal to be reproduced. When playing, the band-shaped cracks appear on the playback screen and become an eyesore.

The present invention 3) superimposes a DC level on the blank part where no video signal occurs in the video part of a high-definition signal that has been down-converted to the NTSC system to increase the brightness of the blank part, so that the part showing the video signal and the blank part The purpose of this invention is to prevent the occurrence of band-like glare at the boundaries between picture areas by keeping the changes in the light emission characteristics of the phosphors of the cathode ray tubes substantially the same.

[Means to solve the problem]

As shown in FIG. 1, the NT
The video signal of the high-definition signal that has been down-converted to the SC system is input to the selector 2, and by the signal added from the video blank signal generator 4 at the selector 2, the high-definition signal generated by down-converting to the NTSC system is input. The selector 2 outputs a video signal in which a direct current of a predetermined level is superimposed on a blank portion of the video signal.

[Effect]

As shown in FIG. 2, the present invention has the above-described configuration.
The selector 2 synthesizes the video blank signal waveform 1, in which the DC level superimposed on the upper blank portion and the lower blank portion is adjusted to a predetermined value, with the waveform V representing the video signal of the high-definition signal down-converted to the SC system. , the selector 2 outputs the video signal waveform (8) with the brightness of the blank portion increased.

Therefore, the output has the same aspect ratio of 9:16.
Even if the display is displayed for a long time on the screen of a television that plays back NTSC signals, the brightness level of the blank areas is raised, so that the changes in the luminescent characteristics of the cathode ray tube's phosphor in the areas where the video signal is displayed and the blank areas are almost the same. It is possible to prevent the occurrence of burning at the border.

〔Example〕

FIG. 1 shows a high-definition signal showing an embodiment of the present invention.
This is an electric circuit block diagram of a converter for converting to TSC, and a video signal of a high-definition signal as shown by waveform V in FIG. has been done.

Reference numeral 4 denotes a video blank signal generator, and the level of the video blank signal generated can be adjusted by a rotary switch 5 connected to the video blank signal generator 4, as shown in waveform 1 in FIG. In this way, the level of the video blank signal is set to a predetermined level, outputted from the video blank signal generator 4, and inputted to the selector 2.

The selector 2 receives a video signal of a high-definition signal down-converted to the NTSC system as shown in the waveform V in FIG. The selector 2 outputs the signals ■ and ■1 alternately, and the waveform V is output during the vertical synchronization signal period, and the waveform ■■ during the upper blank period. 1 is outputted, waveform ■ is outputted during the video signal period, and waveform V is outputted during the lower blank period, so that the upper blank part and the lower part are A video signal in which a direct current is superimposed on the blank portion to increase the brightness of the blank portion is output from the selector 2, and is supplied to the output terminal 3 as a video output signal.

In FIG. 1, a digital signal output is used as the video blank signal generator 4, and the digital signal output is switched by a rotary switch 5 to make the output level of the digital signal variable. When the video signal input and video signal output are digital signals, a digital compatible selector 2 is used.

If the video signal input and video signal output are analog signals, the output of the video blank signal generator 4 may be input to the selector 2 via a D/A converter.

〔Effect of the invention〕

As explained above, according to the present invention, a DC level is superimposed on the blank portion where no video signal occurs in the video portion of a high-definition signal that has been down-converted to the NTSC system, and the brightness of the blank portion is increased, thereby increasing the brightness of the video signal. By making the changes in the luminescent characteristics of the cathode ray tube's phosphor in the visible and blank areas almost the same, it is possible to prevent band-like glare from occurring at the boundary between the visible and blank areas of the video signal. This greatly contributes to improving the performance of converters that convert high-definition signals to NTSC signals.

[Brief explanation of the drawing]

FIG. 1 shows a high-definition signal showing an embodiment of the present invention.
Electrical circuit block diagram of converter for TSC, 2nd
The figure is an explanatory waveform diagram of a video signal of a high-definition signal down-converted to the NTSC system, and FIG. 3 is an explanatory diagram of a screen display of a television for reproducing an NTSC signal. 1- input terminal, 2-...- selector, 3...-
Output terminal, 4-・Video blank signal generator, 5-...
・Low reswitch. Patent applicant: Fujitsu General Ltd. Figure 1 Figure 3 Figure 2

Claims (2)

[Claims] (1) A converter for converting a high-definition signal into an NTSC signal, which outputs a video signal in which a predetermined level of direct current is superimposed on a blank portion of the video signal of a high-definition signal generated by down-converting to the NTSC system. (2) Consisting of a selector and a video blank signal generator whose brightness level can be adjusted, a high-definition video signal down-converted to the NTSC system is input to the selector, and the selector generates the video blank signal generator. Converting a high-definition signal to NTSC, which is characterized by outputting a video signal in which a predetermined level of direct current is superimposed on the blank portion of the video signal of the high-definition signal generated by down-converting to the NTSC system, using a signal added from the NTSC system. converter.