JP2911259B2 - Television receiver - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a CRT for converting a high definition signal such as a MUSE signal into an NTSC signal.
The present invention relates to a television receiver capable of displaying on a television receiver.

[0002]

2. Description of the Related Art In recent years, high-definition broadcasting using a broadcasting satellite has been put into practical use, and a high-definition screen has been obtained by using a special receiver which forms one screen with approximately twice as many scanning lines as a conventional television receiver. It is possible to watch broadcasts. MUSE (Multiple Sub-Nyqu
ist Sampling Encode) method has been developed.

In such a situation, the MUSE signal is converted to an NTSC signal in response to a request to view a high-definition broadcast using a current television receiver, which is already widely used in ordinary households, without using a special receiver for high-definition television. MUSE / NTSC converters have been developed (for example, the magazine "Television Technology", October 1989, pp. 40-45). According to the MUSE / NTSC converter, a Hi-Vision signal received by a BS tuner is converted into an NTSC signal and supplied to a video input terminal of a television receiver.
Not only broadcast programs, but also high-definition broadcast programs
Can be viewed on one receiver.

[0004] By the way, in the NTSC system television receiver, the aspect ratio of the screen is 4: 3, whereas in the MUSE system it is 16: 9. Also, NTS
In the C system, the number of scanning lines for one screen is 525, whereas in the MUSE system, it is 1,125. Therefore, MU
Assuming that the entire screen with an aspect ratio of 16: 9 by SE broadcasting is not displayed on a CRT screen with an aspect ratio of 4: 3, if the widths of both screens are matched, the entire screen area of an aspect ratio of 4: 3 will be displayed vertically. The width of 75% of the direction becomes the effective display area, and a band-shaped blanking portion is displayed on the upper and lower sides of the screen of the CRT (15) as shown in FIG.

[0005] In this case, 75% of 525 scanning lines out of 525 scanning lines composing the NTSC system screen are effective. In the MUSE / NTSC converter, 1125 scanning lines of MUSE broadcasting are converted into 394 scanning lines. A conversion that reduces to scan lines is required. The ratio of the scanning lines at this time is 2.8.
55: 1, not an integer ratio.

Therefore, in order to perform the conversion of the scanning lines by a simple process, a conversion method of reducing the number of scanning lines of 1125 of MUSE broadcast to 375 at a ratio of 3: 1 is adopted. In this method, the number of scanning lines which should be reduced to 394 lines is reduced to 375 lines.
It is compressed to a ratio of 75/394, ie approximately 95%. Therefore, as shown in FIGS. 4 (a) and 4 (b), the video signal V between the horizontal synchronizing signals H is time-compressed in the horizontal direction, and the width of the screen is also compressed at the same ratio. Without distorting the image sent by
Displayed on RT.

[0007]

However, by compressing the width of the screen to approximately 95% as described above, blanking portions are displayed on the left and right sides of the screen of the CRT (15) as shown in FIG. Becomes In general, in the NTSC system, overscan of about 8% is performed in consideration of the influence of terrestrial magnetism and the like. However, even in this case, since the above-mentioned 95% compression hardly provides a margin for overscan, the horizontal scan is performed. If the synchronization signal and the video signal are slightly out of phase with each other, it is inevitable that blanking portions are displayed on the left and right sides of the screen. If blanking sections are displayed not only on the upper and lower sides of the screen but also on the left and right sides, not only will the screen become difficult to see, but also the viewer will have a problem of feeling uneasy as to whether or not there is an adjustment deviation.

An object of the present invention is to provide a television receiver having a simple configuration in which blanking sections are not displayed on the left and right of the screen.

[0009]

SUMMARY OF THE INVENTION A television receiver according to the present invention has a built-in high-definition / NTSC conversion means (5) for converting a high-definition signal into an NTSC signal.
A first mode for displaying a C broadcast signal on a CRT (15), and a NT mode converted by a Hi-Vision / NTSC conversion means (5)
A second mode for projecting the SC signal on the CRT (15) can be switched and set.

A vertical deflection circuit (18) for switching the amplitude of the vertical deflection sawtooth voltage between large and small, and a horizontal deflection circuit (19) for switching the amplitude of the horizontal deflection sawtooth voltage between large and small.
And a microcomputer (7) connected to both deflection circuits (18) and (19). The microcomputer (7) is configured to control the deflection circuits (18) and (19) when the second mode is set. The amplitude of the sawtooth voltage of the vertical deflection and the horizontal deflection is transmitted as a control signal in which the amplitude of the sawtooth voltage of the vertical deflection and the horizontal deflection in the first mode is increased by the same ratio, respectively. Furthermore, Hi-Vision / NTSC conversion means (5)
Is used to convert HDTV signals to NTSC signals.
Compression is performed only by processing of thinning out scanning lines at regular intervals from the original Hi-Vision signal.

[0011]

In the second mode, vertical and horizontal deflection circuits are provided.
(18) Since the deflection amplitude in (19) is increased and the width and height of the image projected on the screen are enlarged at the same ratio, the width of the screen is reduced to approximately 95% by the HDTV / NTSC conversion means (5). Even when compressed, the enlargement ratio is, for example, 10%.
If it is set to about, no blanking portion is displayed on the left and right of the screen. In addition, since the enlargement ratios of the amplitudes of the vertical deflection and the horizontal deflection are set to the same value, no distortion occurs in the image, and the circularity of the image is maintained.

[0012]

According to the television receiver of the present invention, the amplitudes of the vertical and horizontal deflection circuits (18) and (19) can be simply adjusted without changing the conversion method by the high definition / NTSC conversion means (5). A blanking display on the left and right sides of the screen can be prevented with a simple configuration that only enlarges. The HD / NTSC conversion means (5) converts the HD signal to N
When converting to a TSC signal, compression is performed only by thinning out scanning lines at regular intervals from the original Hi-Vision signal.
The circuit configuration of the high definition / NTSC conversion means (5) can be simplified.

[0013]

The examples are illustrative of the present invention and should not be construed as limiting the invention described in the claims or reducing the scope thereof.

FIG. 1 shows a configuration of a television receiver embodying the present invention. The television signal selected by the UV tuner (1) is detected by a detection circuit (2) and output as a composite video signal. The composite video signal is sent to a video circuit (8) and a sync separation circuit (9) through a changeover switch (6), and the video circuit
The signal is converted into an RGB signal by (8), and a vertical synchronizing signal of 60 Hz and 15.75 K
Hz horizontal sync signal is separated. The output of the video circuit (8) is sent to the CRT (15) via the drive circuit (10).

The vertical synchronization signal and the horizontal synchronization signal are sent to a vertical oscillation circuit (11) and a horizontal oscillation circuit (13), respectively.
The resulting sawtooth voltage is amplified and shaped by the vertical output circuit (12) and the horizontal output circuit (14), and then applied to the CRT (15).

On the other hand, M which is selected by the BS tuner (3)
The USE signal is supplied to a MUSE / NTSC converter (5) via a detection circuit (4) and is converted into an NTSC signal.
The MUSE / NTSC converter (5) performs the above-described scan line conversion and time compression in the horizontal scanning direction, and its specific configuration is the same as that of the conventional one. MUSE /
The NTSC signal from the NTSC converter (5) passes through a changeover switch (6) and a video circuit (8) and a sync separation circuit (9).
Led to.

The mode switching and channel selection operation by the viewer are performed by, for example, key operation of a remote controller, and the operation signal is supplied to the microcomputer (7). Also, M
The USE / NTSC converter (5) supplies the MUSE / NTSC determination signal representing the input to the microcomputer (7) simultaneously with the input of the MUSE signal.

Based on the operation signal and the MUSE / NTSC determination signal, the microcomputer (7)
S tuner (3), changeover switch (6), vertical output circuit (1
2) to control the horizontal output circuit (14) and the like.

[0019] FIG. 2 shows a configuration example of a vertical deflection circuit (18) including a vertical oscillation circuit (11), by closing the switch (16), connected in parallel with the first resistor R ₁ Comprises a _second resistor R2 to be implemented. The amplitude of the vertical sawtooth voltage is increased or decreased by opening or closing the switch (16) by a switching signal from the microcomputer (7).
When the determination signal of the MUSE signal input is sent from the MUSE / NTSC converter (5), the amplitude of the vertical sawtooth voltage is increased by about 7 to 8%.

Meanwhile, FIG. 3 shows a configuration example of a horizontal deflection circuit (19) including a horizontal output circuit (14), by closing the switch (17), parallel with the third resistor R ₃ and it comprises a fourth resistor R ₄ to be connected to. By the switching signal from the microcomputer (7), the switch (1)
By opening and closing 7), the amplitude of the horizontal sawtooth voltage can be switched between large and small, and MUSE / NTSC
When the determination signal of the MUSE signal input is sent from the converter (5), the amplitude of the horizontal sawtooth voltage is increased at the same rate as the amplitude of the vertical sawtooth voltage.

According to the above television receiver, the MUS
When converting E-broadcast to NTSC format and projecting it on the screen,
The output of the MUSE / NTSC converter compressed in the horizontal direction as shown in FIG.
In addition, the deflection swing width of the horizontal deflection circuit (19) is enlarged from the chain line in FIG. As a configuration for this, a switch and a resistor capable of opening and closing control are added to the conventional vertical deflection circuit (18) and horizontal deflection circuit (19), and the software of the microcomputer (7) is slightly added. You just need to fix it. Since both the vertical width and the horizontal width of the screen are enlarged at the same rate, the roundness of the image does not decrease.

By the way, when the functions and features related to the satellite broadcasting of the television receiver are displayed on-screen in the ordinary NTSC system, the screen of the CRT (15) as shown in FIG. Displaying a strip-shaped blanking portion at the top and bottom is performed. In this case, in the conventional television receiver, the channel selection microcomputer counts the horizontal synchronization signal from the time when the vertical synchronization signal is generated, and based on the counted value, the blanking display section at the top and bottom of the screen. Since the start and end positions are determined, the start and end positions of the blanking display section become discrete corresponding to one cycle of the counting operation. As a result, there is a problem that blanking portions are not formed at the top and bottom of the screen as shown in FIG.

To solve this problem, if the vertical width and the horizontal width of the screen are enlarged by a certain ratio as in the present invention, a normal simulated demonstration screen as shown in FIG. 8 can be generated without damaging the background screen. Can be done.

The description of the above embodiments is for the purpose of illustrating the present invention and should not be construed as limiting the invention described in the appended claims or reducing the scope thereof. Further, the configuration of each part of the present invention is not limited to the above-described embodiment, and it is needless to say that various modifications can be made within the technical scope described in the claims.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a television receiver embodying the present invention.

FIG. 2 is a circuit diagram showing a configuration example of a vertical deflection circuit.

FIG. 3 is a circuit diagram illustrating a configuration example of a horizontal deflection circuit.

FIG. 4 is a time chart for explaining a compression operation of a video signal by a MUSE / NTSC converter.

FIG. 5 is an explanatory diagram showing how the vertical and horizontal deflection swing widths are enlarged.

FIG. 6 is a diagram showing an example in which an entire screen of a video signal converted by a MUSE / NTSC converter is displayed on the screen with an aspect ratio of 4: 3.

FIG. 7 is a diagram showing an example in which an entire screen of a video signal obtained by compressing the output of a MUSE / NTSC converter is displayed on the screen at an aspect ratio of 4: 3.

FIG. 8 is a diagram showing an example of a screen of a simulated demonstration of satellite broadcasting.

FIG. 9 is a diagram illustrating a problem when the screen of FIG. 8 is displayed.

[Explanation of symbols]

 (5) MUSE / NTSC converter (18) Vertical deflection circuit (19) Horizontal deflection circuit

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI H04N 11/20 H04N 11/20

Claims (2)

(57) [Claims] An HDTV / NTSC conversion means (5) for converting a HDTV signal into an NTSC signal is built-in.
A first mode for displaying a TSC broadcast signal on a CRT (15);
In a television receiver in which the NTSC signal converted by the HDTV / NTSC conversion means (5) can be switched and set to a second mode for displaying on a CRT (15), the amplitude of the sawtooth voltage for vertical deflection is increased or decreased. A vertical deflection circuit (18) for switching, a horizontal deflection circuit (19) for switching the amplitude of the sawtooth voltage for horizontal deflection to large or small, and both deflection circuits (18)
A microcomputer (7) connected to (19),
When the second mode is set, the microcomputer 7 sets the amplitude of the sawtooth voltage of the vertical deflection and the horizontal deflection to the deflection circuits 18 and 19 so that the vertical deflection and the horizontal deflection in the first mode are changed. A control signal is transmitted to increase the amplitude of the deflection sawtooth voltage at the same ratio, and when the second mode is set, the horizontal width and the vertical width of the image displayed on the screen are expanded at the same ratio, thereby increasing the screen. A television receiver, wherein blanking portions are prevented from being displayed on the left and right, and vertical and horizontal distortion of an image is prevented. 2. HDTV / NTSC conversion means (5)
Is used to convert HDTV signals to NTSC signals.
2. The television receiver according to claim 1, wherein compression is performed only by processing of thinning out scanning lines at regular intervals from the original Hi-Vision signal.