JPH04270581A - Muse/ntsc converter and ntsc receiver - Google Patents

Abstract

PURPOSE:To obtain the vertical resolution equivalent to that of an NTSC signal and to display an HDTV broadcast signal while left and right edges of the picture are not cut off by controlling a time axis conversion section, Y, C signal insert sections and a scanning line conversion section respectively independently so as to display a picture in the squeeze mode. CONSTITUTION:The receiver is provided with a time axis conversion section 1 similar to that of an NTSC receiver, a Y signal insert section 2, a scanning line number conversion section 3 and a C signal insert section 4, and also with an operation switch 5 for display mode selection, a mode control section 6, and a mode decoder 7 discriminating the display mode based on an output of the mode control section 6 and controlling a vertical deflection circuit 8 in the squeeze mode. Then the time axis conversion section 1, the Y signal insert section 2, the scanning line number conversion section 3 and the C signal insert section 4 are controlled respectively independently and the mode in which the vertical resolution is equivalent to the zoom-up mode and left and right edges of a picture are not cut off is provided to vary the vertical deflection of the monitor.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention provides H
M that converts DTV broadcast signals to NTSC TV signals
The present invention relates to a USE/NTSC converter, and particularly to a MUSE/NTSC converter and an NTSC receiver that select and control a mode for displaying HDTV broadcast images on an NTSC monitor.

0002

[Prior Art] Using the MUSE system, high-definition (HDTV) programs broadcast via broadcasting satellites can be received not only by HDTV-dedicated receivers, but also by NTs used to receive standard television broadcasts by the conventional NTSC system.
A MUSE/NTSC converter has been developed that converts an HDTV broadcast signal based on the MUSE system into a TV signal based on the NTSC system so that it can be enjoyed even with an SC receiver. This converter uses an HDT with an aspect ratio of 16:9.
In order to display the V image on an NTSC monitor with an aspect ratio of 4:3, a wide mode as shown in FIG. 4 and a zoom-up mode as shown in FIG. 5 are adopted. In the wide mode, an image with an aspect ratio of 16:9 is displayed inside a screen with an aspect ratio of 4:3 by blanking the upper and lower ends of the screen to make it blackish. In the zoom-up mode, there are no dark areas at the top and bottom edges of the screen, but instead the images at the left and right edges are cut off by 25% of the entire image.

MUSE/NT using these display modes
A conventional MUSE/NTSC converter that performs SC conversion will be described with reference to FIG. 3.

The received MUSE signal is quantized by an A/D (analog-digital) converter (not shown), and then subjected to HDTV signal processing such as de-emphasis. It will be done. The time axis converter 1 is
It has a buffer memory, and using this buffer memory,
One line of the MUSE signal is NTSC.
The time axis is converted so that it becomes one line of the signal. At this time, the frequency of the write clock of the buffer memory is 16
．． Although it is fixed at 2 MHz, the frequency of the read clock is changed depending on the display mode described above. That is, the frequency is 7.37 MHz in the wide mode, and 5.04 MHz in the zoom up mode. The mode control section 12 outputs a 1-bit control signal corresponding to the mode information output from the operation switch (SW) 11, which is selected by the viewer as the display mode, and the time axis conversion section 1, It controls the Y signal interpolation section 2, the C signal interpolation section 4, and the scanning line number conversion section 3.

[0005] In addition, in the time axis conversion unit 1, in the case of the MUSE signal, 516 scanning lines per field are converted into
After applying a pre-filter, it is thinned out to 1/2 and converted to NTSC 525 series. Thereafter, the Y and C signal interpolators 2 and 4 perform TCI decoding and interpolate both the Y and C signals. The scanning line number converter 3 performs prefiltering only in the wide mode to thin out the scanning lines to 2/3. In zoom-up mode, the signal is passed through without any processing.

[0006]

[Problem to be solved by the invention] The above-mentioned conventional MUS
In the E/NTSC converter, in wide mode, the number of scanning lines of the image is thinned out to 2/3, so the vertical resolution is NTSC.
There was a problem in that the left and right edges of the wide image were cut off in the zoom-up mode.

The present invention has been made in view of the above problems, and is a MUSE system that can obtain a vertical resolution comparable to NTSC without cutting off the left and right edges of the image of an HDTV broadcast signal based on the MUSE system. /NTSC converter and NTSC receiver.

[0008]

[Means for solving the problem] MUSE/
The NTSC converter thins the number of scanning lines of the HDTV broadcast signal to 1/2, and when in wide mode, the horizontal component of the HDTV broadcast signal fits within the NTSC screen, and when in zoom-up mode, the horizontal component of the HDTV broadcast signal A time axis conversion unit and a Y and C signal interpolation unit that allow a part of the components to fit within the NTSC screen, and a scan that is thinned out to 1/2 by the time axis conversion unit in the wide mode. A scanning line number converter that further thins out the number of lines to 2/3 and leaves the number of scanning lines that was thinned out to 1/2 in the time axis converter as it is in the zoom-up mode, and these time axis converters and Y
and a mode control section that controls a C signal interpolation section and a scanning line number conversion section according to each of the modes, and a MUSE/NTSC converter that converts an HDTV broadcast signal according to the MUSE system into a TV signal according to the NTSC system. , the mode control section independently controls the time axis conversion section, the Y and C signal interpolation section, and the scanning line number conversion section, and the time axis conversion section and the Y and C signal interpolation section are the same as in the wide mode. The scanning line number converter is characterized by comprising means for controlling to a squeeze mode similar to the zoom-up mode.

The NTSC receiver according to the present invention has the above-mentioned M
The device is characterized in that it includes a built-in USE/NTSC converter, and includes means for reducing the amplitude gain of the vertical deflection circuit in the squeeze mode in conjunction with the mode control section.

0010

[Operation] In the MUSE/NTSC converter of the present invention, the time axis converter, the Y and C signal interpolators, and the scanning line number converter 3 are each independently controlled, and the vertical resolution is the same as that in the zoom-up mode. It is possible to display an image in squeeze mode where the left and right sides of the image are not cut.

In the NTSC receiver of the present invention, in conjunction with the mode switching of the MUSE/NTSC converter described above, in the squeeze mode, an image with high vertical resolution and no distortion is obtained by changing the vertical deflection of the monitor. .

0012

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

FIG. 1 shows a MUSE according to an embodiment of the present invention.
1 shows the configuration of the main parts of an NTSC receiver having a /NTSC converter.

The NTSC receiver shown in FIG. 1 includes a time axis conversion section 1, a Y signal interpolation section 2, a scanning line number conversion section 3, and a C signal interpolation section similar to the conventional NTSC receiver shown in FIG. (TCI
(including a decoder). The NTSC receiver in FIG. 1 further includes an operation switch 5 for selecting a display mode, a mode control section 6, and a squeeze mode (details will be described later) for determining the display mode based on the output to the mode control section 6.
A mode decoder 7 that sometimes controls a vertical deflection circuit 8 is also provided.

[0015] In such a configuration, the received MU
The SE signal is A/D converted, quantized, and further subjected to signal processing such as de-emphasis, and then provided to the time axis converter 1. The time axis conversion unit 1 uses a buffer memory to perform time axis conversion so that one line of the MUSE signal becomes one line of the NTSC signal. At this time, the frequency of the write clock of the buffer memory is fixed at 16.2 MHz, but the frequency of the read clock is changed depending on the display mode. That is, the frequency is 7.37 MHz in wide mode and squeeze mode, and 5.04 MHz in zoom up mode. The display mode is determined by a 1-bit control signal sent from the mode control section 6 to the time axis conversion section 1, the Y signal interpolation section 2, and the C signal interpolation section according to the mode information output from the switch 5 selected by the viewer. 4 and the scanning line number converter 3, and these control signals cause the time axis converter 1, the Y signal interpolator 2, the C signal interpolator 4, and the scanning line number converter 3 to mutually independently controlled.

In the time axis conversion unit 1, in the case of the MUSE signal, the scanning lines, which are 516 lines per field, are converted into NTS
Convert to C 525 line system. Thereafter, the Y and C signal interpolators 2 and 4 perform TCI decoding and interpolate both the Y and C signals. The scanning line number converter 3 performs prefiltering only in the wide mode to thin out the scanning lines to 2/3. In zoom-up mode and squeeze mode, the signal is passed through without any processing.

In the MUSE/NTSC converter of the present invention, the mode control section 6 independently controls the mode of the time axis conversion section 1 and the Y and C signal interpolation sections 2 and 4 and the mode control of the scanning line number conversion section 3. A squeeze mode as shown in FIG. 2 has been added as a display mode that can be selected using the operation switch 5. In this squeeze mode, the entire HDTV image is displayed as shown in FIG. 2, but unlike in the wide mode, the number of scanning lines is not thinned out to 2/3. Therefore, if the image is displayed as is on a monitor with an aspect ratio of 3:4, the image will be vertically long. Therefore, the mode decoder 7 controls the amplitude gain of the vertical deflection circuit 8 of the monitor during the squeeze mode to reduce the amplitude to obtain an image with a normal ratio.

In this way, in a receiver with a built-in converter, by linking the mode control in the squeeze mode and the gain control of the vertical deflection circuit 8, when the viewer changes the mode of the receiver, the vertical This eliminates the need to change the gain of the deflection circuit 8.

Note that the mode control section 6 and the vertical deflection circuit 8 are not interlocked by the mode decoder 7, but the gain of the vertical deflection circuit 8 can be changed by the viewer by operating a switch or the like when the squeeze mode is selected. You can also do this.

[0020]

As described above, according to the present invention, the time axis converter, the Y and C signal interpolators, and the scanning line number converter 3 are each independently controlled to display an image in squeeze mode. By doing so, the MUSE/NTSC converter is capable of obtaining a vertical resolution equivalent to NTSC from HDTV broadcast signals using the MUSE method without cutting off the left and right edges of the image, and in conjunction with mode switching in the squeeze mode. It is possible to provide an NTSC receiver that can control vertical deflection to obtain images with high vertical resolution and no distortion.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of the main parts of an NTSC receiver having a MUSE/NTSC converter according to an embodiment of the present invention.

FIG. 2 is a schematic diagram for explaining an example of display in squeeze mode in the embodiment of FIG. 1;

FIG. 3 is a block diagram showing an example of the configuration of main parts of an NTSC receiver having a conventional MUSE/NTSC converter.

FIG. 4 is a schematic diagram for explaining an example of wide mode display.

FIG. 5 is a schematic diagram for explaining an example of display in zoom-up mode.

[Explanation of symbols]

1; Time axis conversion section 2; Y signal interpolation unit 3; Scanning line number converter 4; C signal interpolation unit 5; Operation switch 6; Mode control section 7; Mode decoder section 8; Vertical deflection circuit

Claims (2)

[Claims] [Claim 1] The number of scanning lines of an HDTV broadcast signal is halved.
In addition, when in wide mode, the horizontal component of the HDTV broadcast signal is made to fit within the NTSC screen, and when in zoom-up mode, a part of the horizontal component of the HDTV broadcast signal is made to fit within the NTSC screen. The time axis conversion section and the Y and C signal interpolation section. In the wide mode, the number of scanning lines that was previously thinned out to 1/2 in the time axis conversion section is further thinned out to 2/3, and in the zoom up mode, A scanning line number converting section that leaves the number of scanning lines thinned out to 1/2 in the time axis converting section as is, these time axis converting sections, and Y and C.
It has a mode control section that controls the signal interpolation section and the scanning line number conversion section according to each mode,
M that converts DTV broadcast signals to NTSC TV signals
In the USE/NTSC converter, the mode control section independently controls the time axis conversion section, the Y and C signal interpolation section, and the scanning line number conversion section, so that the time axis conversion section and the Y and C signal interpolation section M characterized in that the scanning line number converting section is provided with means for controlling to a squeeze mode, which is similar to the wide mode, and which is similar to the zoom up mode.
USE/NTSC converter. [Claim 2] MUSE/NTSC according to claim 1
NTSC comprising a built-in converter and means for reducing the amplitude gain of the vertical deflection circuit during the squeeze mode in conjunction with the mode control section.
Receiving machine.