JPH0246071A - Television receiver - Google Patents

Abstract

PURPOSE:To ensure a correct aspect ratio by converting the number of scanning lines into 525 without cutting off both ends to a MUSE signal and changing a vertical deflection width. CONSTITUTION:The MUSE signal inputted from an input terminal 1 is quantized by an A/D converter 2 and its frequency characteristic is corrected by a deemphasis circuit 3. The corrected signal is inputted at a scanning line conversion circuit 5. In the scanning line conversion circuit 5, 1050 out of 1125 are written into a memory, read out at a lower speed than a writing speed and thus, they are converted into the signal of 1050/frame, 2:1 interlace and field frequency 60Hz. The deflection timing of a CRT is made by a 525/60Hz timing generating circuit 13 and drives a vertical deflection circuit 14 and a horizontal deflection circuit 15. A switch 9 selects the output of a D/A converter 8, controls the vertical deflection circuit 14 and reduces the deflection width to a W2. Thus, a longitudinal picture is corrected properly.

Description

[Detailed description of the invention] [Industrial application field] This invention relates to a television receiver.

[Conventional technology]

FIG. 3 shows a television receiver using the MUSE-525 converter, which was reported at the Institute of Electronics, Information and Communication Engineers Spring National Conference D-169. In the figure, 1 is an input terminal,
2 is an A/D converter, 3 is a de-emphasis circuit, and 4 is a P
LL circuit, 5 is a 1125-1050 scanning line conversion circuit that converts 1125 scanning lines to 1050 scanning lines, 6
7 is a luminance signal processing circuit that performs intra-field interpolation of the luminance (Y) signal and interlace conversion of 1050 lines to 525 lines, and 7 is a luminance signal processing circuit that performs intra-field interpolation of the color difference (C) signal and TC.
A color difference signal processing circuit that performs I decoding and 525-line interlace conversion, 8 is a D/A converter, 9 is a switch, 10 is an inverse matrix circuit, 16.17 is an input terminal, 18 is N
It is a TSC decoder.

Next, the operation will be explained. A high-definition signal band-compressed by the MUSE method is input from an input terminal l. The high-definition signal has 1125 scanning lines, a field frequency of 60 Hz, and a 2:1 interlace signal. In the MUSE method, this high-definition signal is transmitted at 8MHzl.
Bandwidth compression for channels. Compression is performed by offset subsampling, using inter-field and inter-frame offsets for static parts and inter-line offsets for moving parts. In addition, two color difference signals (hereinafter referred to as C signals) are transmitted in one channel.
, RY, and B-Y are time-compression multiplexed during the blanking period of the luminance signal (hereinafter referred to as Y signal).

The input MUSE signal is quantized by the A/D converter 2 and input to the PLL circuit 4. In PLL circuit 4, MU
A correct sampling clock is reproduced based on the phase information in the SE signal. The signal sampled with the correct phase in this manner has its frequency characteristics corrected by the de-emphasis circuit 3.

The corrected signal is converted by the 1125-1050 scanning line conversion circuit 5 into a signal of 1050 lines/frame. The conversion method in this case is as shown in Figure 4 (
Of the 1,125 scanning lines in the image a), a total of 75 scanning lines in the upper and lower parts A and H are discarded, resulting in 1,050 scanning lines. Since high-definition images handle images with an aspect ratio of 9:16, they cannot be displayed on a conventional 3:4 CRT. Therefore, the scanning line conversion circuit 5 discards some of the scanning line information (75 lines) as described above, and also discards the information C and D at both the left and right ends, thereby converting it into information with 1050 lines/frame and an aspect ratio of 3:4. The image shown in FIG. 4(b) is obtained.

The signal converted in this way is divided into a Y signal and a C signal and processed. The Y signal processing circuit 6 performs intra-field interpolation corresponding to line offset subsampling to restore the band to its original value. Thereafter, the signals are converted into 525 interlaced signals and converted into analog signals by the D/A converter 8.

On the other hand, the C signal processing circuit 7 time-expands the two time compression multiplexed (TC) C signals RY and B-Y and performs field interpolation to restore the original band.

Thereafter, it is converted into a 525-line interlaced signal and subjected to D/A conversion to obtain two 525-line interlaced signals, RY and BY. Y, RY, B-Y obtained as above
is selected by the changeover switch 9, converted to RGB by the inverse matrix 10, and displayed on the CRT II. On the other hand, the NTSC signal inputted from the input terminal 17 is demodulated into Y, R-Y, and B-Y by the NTSC decoder 18, selected by the changeover switch 9, and inputted to the inverse matrix 10.

Switch 9 is controlled by a signal from input terminal 16.

Now, the output of D/A converter 8 is NTSC decoder 1 with 525 interlaced lines and a field frequency of 60 Hz.
Since the output is the same as that of CRT 8, by switching with switch 9 it is possible to display on the same CRT.

[Problem to be solved by the invention]

Since conventional television receivers are configured as described above, there is a problem in that video information at both ends of high-definition is discarded.

This invention was made to solve the above-mentioned problems, and aims to provide a television receiver that can monitor almost full-screen high-definition images and also receive conventional NTSC (No. 3). purpose.

[Means to solve the problem]

The television receiver according to the present invention includes means for converting the number of scanning lines from 1125 to 525, a switch for switching between the converted signal and the NTSC signal, and a vertical deflection width that changes in conjunction with the switch. It is equipped with means.

[Effect]

In the television receiver of this invention, the number of scanning lines is reduced to 525 without cutting off both ends for the MUSE signal manually.
The correct aspect ratio is ensured by changing the vertical deflection width, while for NTSC input the vertical deflection width is returned to its normal state.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a television receiver according to an embodiment of the present invention, in which 1 is an input terminal for inputting an MLISE signal, 2 is an A/D conversion circuit, 3 is a de-emphasis circuit,
4 is a first PLL circuit that reproduces the clock, 5 is a scanning line conversion circuit that converts the number of scanning lines from 1125 to 1050, 6 is a luminance signal processing circuit, 7 is a color signal processing circuit, and 8 is a D/A Converter circuit, 9 is a switch for switching two systems of Y, R-Y, B-Y signals, 10 is a CRT, 12 is a second P
LL circuit, 13 is HD that drives the deflection circuit.

14 is a vertical deflection circuit, 15 is a horizontal deflection circuit, 16 is an input terminal for inputting a switching signal for the switch 9, 17 is an input terminal for an NTSC signal, and 18 is an NTSC decoder.

A MUSE signal input from an input terminal 1 is quantized by an A/D converter 2, and a clock is regenerated by a PLL circuit 4. On the other hand, the frequency characteristics of the quantized signal are corrected by a de-emphasis circuit 3. The corrected signal is input to the scanning line conversion circuit 5. 11 in the scanning line conversion circuit 5
1050 lines out of the 25 lines are written into the memory, and by reading them out at a speed slower than the writing speed, they are converted into a signal of 1050 lines/frame, 2:1 interlace, and a field frequency of 60 Hz.

The above conversion output is processed by two systems, Y and C. First, in the Y signal processing circuit 6, the band is restored to its original value by intra-field interpolation processing, and the band is converted from 1050 lines to 525 lines interlaced. The signal obtained in this way is converted into an analog signal by the D/A converter 8. On the other hand, since the C signal is time compression multiplexed during the blanking period of the Y signal,
The C signal processing circuit 7 performs time expansion (TCI decoding).

Furthermore, the band is restored to its original value by field interpolation and converted to 525 lines, and outputs R-Y and B-Y.The signals obtained in the manner above 0 are converted into analog signals by the D/A converter 8 in the same way as the Y signal. is converted to

The Y, RY, and BY signals obtained as described above are selected by the switch 9, converted into RGB by the inverse matrix circuit 10, and displayed on the CRT II. CRT deflection timing is generated by a 525 line/60Hz timing generation circuit 13, a vertical deflection circuit 14 and a horizontal deflection circuit 15.
to drive.

These circuits have almost the same speed as normal NTSC (
Horizontal deflection frequency fx = 15.75KHz.

It operates at a vertical deflection frequency of 60 Hz).

The image obtained in the above case is obtained by converting only the number of scanning lines of the high-definition image shown in FIG. Therefore, as shown in FIG. 2(b), the vertical deflection width W1 is large, resulting in a vertically long image. In order to correct this vertically long state, the MUSE/NTSC input from the input terminal 16
When the selection signal for selecting one of them selects MUSE, the switch 9 selects the output of the D/A converter 8, and controls the vertical deflection circuit 14 to reduce the vertical deflection width to W2. . As a result, a vertically long image as shown in FIG. 2 (C1) is corrected correctly.

On the other hand, the NTSC signal input from input terminal 17 is
It is decoded into Y, RY, and B-Y by the SC decoder 18 and enters the switch 9. When the MUSE/NTSC selection signal selects NTSC, switch 9 is set to NTSC.
While selecting the output of the SC decoder 18, the vertical deflection circuit 14 is operated to set the normal vertical deflection width Wl.

Note that in the above embodiment, the interpolation process and the conversion to 525 interlaced lines are performed after performing the conversion from 1125 lines to 1050 lines, but the interpolation process is performed first and then the 1 line conversion is performed.
Interlace conversion from 125 lines to 525 lines may be performed.

Further, in the above embodiment, 1050 out of 1125 lines are extracted and converted into 525 scanning lines, but all 1125 lines may be converted into 525 scanning lines.

〔Effect of the invention〕

As described above, according to the present invention, for the MUSE signal manually, the number of scanning lines is converted to 525 without truncating both ends, and the correct aspect ratio is ensured by changing the vertical deflection width, while the NTSC Since the vertical deflection width was returned to the normal state for human power, the MUSE signal and NTSC
Both signals can be monitored, and MUS
For the E signal, almost the entire screen was converted, so
This has the effect of reducing the amount of information thrown away.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a television receiver according to an embodiment of the present invention, FIG. 2 is a diagram explaining the operation of FIG. 1, and FIG. 3 is a block diagram showing a conventional television receiver. Figure 4 shows the operation of Figure 3, 7 is a color difference signal processing circuit, 9 is a switch, and 14 is a vertical deflection circuit (vertical deflection width variable means).
It is. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] (1) In a television receiver that receives MUSE signals and NTSC signals as input signals, there is a scanning line number conversion means that converts 1125 scanning lines of the MUSE signal into 525 scanning lines, and a scanning line number conversion means that converts the 1125 scanning lines of the MUSE signal into 525 scanning lines. What is claimed is: 1. A television receiver comprising: a switch for switching between an NTSC signal and an NTSC signal according to the switching signal; and vertical deflection width variable means for changing a vertical deflection width in conjunction with the switch.