JPH05292510A - Television set - Google Patents

Abstract

(57) [Abstract] [Purpose] Even when the video displayed on the picture tube is switched to a broadcasting system with a different aspect ratio of the screen, the viewer should not feel the difference in brightness and color of the screen. [Structure] The CRT drive circuit 7 has two color temperature setting sections for high-definition TV broadcasting and NTSC system, and selects the color temperature setting section when the switching control signal f1 is at high level. When the switching control signal f1 is at the low level, the color temperature setting section for the NTSC system is selected. The CRT drive circuit 7 uses the color difference signal g1 and the luminance signal h1 to determine RG.
A B3 primary color signal is created, and a drive current i1 is created based on this RGB3 primary color signal and using the selected color temperature setting unit, is supplied to the CRT 8, and is displayed on the CRT 8. As a result, the image displayed on the CRT8 is NTSC.
It is possible to prevent the viewer from feeling the difference in screen brightness and color when the system is switched to high-definition TV broadcasting.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention displays a television broadcast signal of the first broadcasting system on a picture tube, and a second aspect having a screen aspect ratio larger than that of the first broadcasting system.
The present invention relates to a television receiver that displays a television broadcast signal of the above-mentioned broadcasting system on a picture tube in a state where the vertical direction of the screen is compressed, and in particular, a viewer has a difference in luminance between broadcast images of the first and second broadcasting systems. Also, the present invention relates to a television receiver capable of preventing a color difference from being felt.

[0002]

2. Description of the Related Art The NTSC system with an aspect ratio of 4: 3 has been used as a television broadcast in Japan, but in recent years, as a new television broadcast, an experimental broadcast of a high-definition TV broadcast with an aspect ratio of 16: 9. Is starting to take place.

Since it is difficult in terms of cost to rapidly popularize such a device for directly receiving a high-definition TV broadcast in general households, a MUSE-NTSC television receiver for receiving a normal NTSC television broadcast is used. A device such as a television receiver that has a built-in converter and converts a high-definition TV broadcast into an NTSC system by using a MUSE-NTSC converter and then displays an image with an aspect ratio of 16: 9 in the NTSC system has been put on the market. ..

FIG. 3 is a block diagram showing such a conventional television receiver. In FIG. 3, for simplification of the description, circuits such as a UHF / VHF system diagram for terrestrial broadcasting and a deflection circuit are omitted.

Reference numeral 51 is a parabolic antenna that captures satellite broadcast radio waves, and the satellite broadcast radio waves a2 captured by the parabolic antenna 51 are converted into electrical signals b2 and B
It is supplied to the S tuner 52. The BS tuner 52 selects the electric signal b2 from the parabolic antenna 51,
The BS-IF signal c2 is created and supplied to the video processing circuit 53 and the MUSE-NTSC converter 54. The video processing circuit 53 converts the BS-IF signal c2 into a video signal d2 of NTSC system and guides it to the first input terminal of the switching circuit 55. The MUSE-NTSC converter 54 is a BS
Detecting the presence or absence of a MUSE signal for the IF signal c2,
If there is a MUSE signal, NT which compresses this MUSE signal in the vertical direction of the screen and inserts a black video display section at the top and bottom of the screen.
The video signal e2 of the SC system is converted and supplied to the second input terminal of the switching circuit 55. In addition, MUSE-NTSC
The converter 54 creates the switching control signal f2 based on the detection result of the presence or absence of the MUSE signal, and supplies it to the switching signal input terminal of the switching circuit 55. In this case, the switching control signal f2 becomes high level when the detection result of the MUSE signal is present, and becomes low level when there is no detection result.

The switching circuit 55 is provided for the MUSE-NTSC converter 5 when the switching control signal f2 is at a high level.
The video signal e2 from 4 is led to the output terminal, and the video signal d2 from the video processing circuit 53 is led to the output terminal when the switching control signal f2 is at the low level. Switching circuit 55
The video signal led to the output terminal of the color signal reproduction circuit 56
Is supplied to. The color signal reproduction circuit 56 includes a switching circuit 55.
The color difference signal g2 from the carrier color signal in the video signal from
Is reproduced and supplied to the CRT drive circuit 57 together with the luminance signal h2 of the video signal.

The CRT drive circuit 57 converts the color difference signal g2 and the luminance signal h2 from the color signal reproducing circuit 56 into R.
(Red) G (green) B (blue) 3 primary color signals are created and
The drive current i2 is created based on the B3 primary color signal and C
An image is displayed on the CRT 58 by being supplied to the RT 58.

According to such a television receiver,
When the BS tuner 52 selects high-definition TV broadcasting, that is, MUSE television broadcasting, MUSE-NT
The SC converter 54 uses the BS-from the BS tuner 52.
The MUSE signal supplied as the IF signal c2 is sent to the NTSC
When the MUSE signal is converted into the video signal e2 of the system and the detection result of the MUSE signal becomes valid and the high level switching control signal f2 is supplied to the switching circuit 55, MUSE-N
The NTSC system video signal e2 in which the vertical direction of the screen is compressed from the TSC converter 54 and black image display portions are inserted above and below the screen is sent to the CRT 58 through the switching circuit 55, the color signal reproducing circuit 56 and the CRT drive circuit 57. Is displayed.

When the BS tuner 52 selects an NTSC television broadcast, the MUSE-NTSC converter 54 outputs a low level switching control signal f2 to the switching circuit 55 because the MUSE signal is not detected. Therefore, the NTSC video signal d2 from the video processing circuit 53 is displayed on the CRT 58 via the switching circuit 55, the color signal reproducing circuit 56 and the CRT drive circuit 57.

In this way, the conventional television receiver can display the NTSC system television broadcast on the CRT and also convert the high-definition TV broadcast to the NTSC system and display it on the CRT.

FIG. 4 is an explanatory view showing an image of a television receiver which receives such a high quality TV broadcast.

In FIG. 4, reference numeral 61 is a CRT shown in FIG.
It is a 58 CRT screen, and the aspect ratio is 4: 3. The aspect ratio is 16: 9 on the CRT screen 61.
The screen 62 is displayed in the central 3/4 area of the CRT screen 61, and black image display portions 63 and 64 are displayed in the upper and lower areas of the screen 62.

Here, the screen 62 for high-definition TV broadcasting is CR
Since the vertical direction is compressed and displayed in the center of the T screen 61, the screen brightness is higher than that of the NTSC television broadcast, and the illusion that it is difficult to see visually or the color changes, and high-definition TV broadcast There was a problem that the sharpness of was lost.

[0014]

In the above-mentioned conventional television receiver, the aspect ratio of the screen is 4: 3.
If you want to display high-definition TV broadcast on the picture tube of
Broadcast images are compressed vertically and displayed, so NT
The screen brightness is higher than that of SC television broadcasting,
There are problems that it is difficult to see visually, the illusion that colors change, and the sharpness of high-definition TV broadcasting is lost.

The present invention eliminates the above-mentioned problems, and even when the image displayed on the picture tube is switched to the image of the broadcasting system having a different aspect ratio of the screen, the difference in brightness and color of the screen is given to the viewer. It is an object of the present invention to provide a television receiver that can be made unnoticeable.

[0016]

SUMMARY OF THE INVENTION A television receiver according to the present invention includes a tuner for producing an intermediate frequency signal by selecting television broadcast signals of the first and second broadcasting systems, and a tuner for producing the intermediate frequency signal. When the intermediate frequency signal is the first broadcasting system, a video processing circuit for converting the intermediate frequency signal into the first video signal of the first broadcasting system, and the intermediate frequency signal from the tuner is the second video signal. In the case of the above broadcasting system, a converter for converting the intermediate frequency signal into a second video signal of the first broadcasting system in a state where the vertical direction of the screen is compressed, and a first converter from the converter and the video processing circuit. And a color signal reproducing circuit for separating the second video signal into a luminance signal and a carrier color signal and reproducing a color difference signal from the carrier color signal, and based on the luminance signal and the color difference signal from the color signal reproducing circuit. A picture tube drive circuit for driving the picture tube in a state in which the color temperature can be adjusted; a judgment means for judging whether the intermediate frequency signal from the tuner is the first broadcasting system or the second broadcasting system; A switching circuit which is provided in a path for supplying the second video signal to the color signal reproducing circuit, and which guides one of the first and second video signals to the color signal reproducing circuit based on the judgment result of the judging means, and the judging means. And a color temperature adjusting means for adjusting the color temperature of the picture tube drive circuit on the basis of the determination result.

[0017]

According to this structure, the judging means judges whether the intermediate frequency signal from the tuner is the first broadcasting system or the second broadcasting system, and the color temperature adjusting means determines the judgment result of the judging means. Since the color temperature of the picture tube drive circuit is adjusted based on the above, the viewer feels the difference in brightness and color of the screen when switching between the first broadcasting system and the second broadcasting system having different screen aspect ratios. You can prevent it.

[0018]

The present invention will be described in detail below with reference to the embodiments shown in the drawings.

FIG. 1 is a block diagram showing a television receiver according to the present invention.

In FIG. 1, a parabolic antenna 1 captures a satellite broadcast radio wave a1, converts it into an electric signal b1 and supplies it to a BS tuner 2. The BS tuner 2 selects the electric signal b1 from the parabolic antenna, creates a BS-IF signal c1, and outputs the video processing circuit 3 and the MUSE-NTS.
It is supplied to the C converter 4. The video processing circuit 3 is a BS
-Convert the IF signal c1 into a video signal d1 and lead it to the first input terminal of the switching circuit 5; The MUSE-NTSC converter 4 detects the presence / absence of a MUSE signal in the BS-IF signal c1, and if there is a MUSE signal, compresses the MUSE signal in the vertical direction of the screen as in the case of the MUSE-NTSC converter 4 in FIG. The converted video signal e1 of the NTSC system is supplied to the second input terminal of the switching circuit 5. Further, the MUSE-NTSC converter 4 creates a switching control signal f1 based on the presence or absence of the MUSE signal and supplies it to the switching circuit 5 and the control signal input terminal of the CRT drive circuit 7. In this case, the switching control signal f1 becomes high level when the detection result of the MUSE signal is present, and becomes low level when there is no detection result.

When the switching control signal f1 from the MUSE-NTSC converter 4 is at a high level, the switching circuit 5 supplies the video signal e1 from the MUSE-NTSC converter 4 to the color signal reproducing circuit 6 and the MUSE-NTS.
When the switching control signal f1 from the C converter 4 is at a low level, the video signal d1 from the video processing circuit 3 is supplied to the color signal reproducing circuit 6. The color signal reproduction circuit 6 reproduces the color difference signal g1 from the carrier color signal in the video signal from the switching circuit 5 and supplies it to the CRT drive circuit 7 together with the luminance signal h1 of the video signal.

The CRT drive circuit 7 is provided with a total of two color temperature setting sections for high-quality TV broadcasting (for MUSE system) and NTSC system, and when the switching control signal f1 is at high level, high quality is provided. When the color temperature setting section for TV broadcasting is selected and the switching control signal f1 is at low level, NTS
Select the color temperature setting unit for the C method. The CRT drive circuit 7 creates RGB3 primary color signals from the color difference signal g1 and the luminance signal h1 from the color signal reproduction circuit 6, and this RGB3
The RGB3 primary color signals are displayed on the CRT 8 by creating the drive current i1 based on the primary color signals and using the selected color temperature setting unit and supplying the drive current i1 to the CRT 8.

FIG. 2 is a circuit diagram showing a G primary color signal circuit system of the color temperature setting section of the CRT drive circuit 7 of FIG.

In FIG. 2, the G primary color signal jG generated by the CRT drive circuit 7 is guided to the input terminal 11, and the switching control signal f1 from the MUSE-NTSC converter 4 is supplied to the input terminal 12. ing. The G primary color signal jG guided to the input terminal 11 is applied to the base of the NPN transistor Tr1. NPN transistor T
The emitter of r1 is the common terminal c of the changeover switch SW1.
It is connected to the. The first output terminal a1 of the changeover switch SW1 is connected to the reference potential point via the resistor R1. The second output terminal a2 of the changeover switch SW1 is
It is connected to the reference potential point via the resistor R2. The changeover switch SW1 selects the first output terminal a1 to connect the emitter of the NPN transistor Tr1 to the reference potential point via the resistor R1 when the changeover control signal f1 is low level, and the changeover control signal f1 is high level. In this case, the second output terminal a2 is selected and the emitter of the NPN transistor Tr1 is connected to the reference potential point via the resistor R2. NP
The emitter of the N transistor Tr1 is connected to the G drive current input terminal 13 of the CRT 8, and the signal from the emitter of the NPN transistor Tr1 is supplied to the CRT 8 as the drive current iG of the G primary color signal jG.

When the BS tuner 2 selects a high-definition TV broadcast, the emitter of the NPN transistor Tr1 is connected to the reference potential point via the resistor R2, and the NPN transistor Tr1 is connected to the reference potential point.
The transistor Tr1 and the resistor R2 form a color temperature setting unit for high quality TV broadcasting. On the other hand, BS tuner 2 is NTS
When the C type television broadcast is selected, the NPN transistor Tr1 and the resistor R1 form a color temperature setting unit for the NTSC system by connecting the emitter of the NPN transistor to the reference potential point via the resistor R1. .. In this way, the drive current iG of the G primary color signal jG is changed to MU.
The SE method and the NTSC method can be set individually.

Although not shown, the color temperature setting unit has a G
As in the case of the primary color signal, a B primary color signal circuit system circuit for processing the B (blue) primary color signal is provided. G
The color temperature of the image displayed on the CRT 8 can be adjusted by adjusting the drive currents of the primary color signal and the B primary color signal.

The operation of such a television receiver will be described below.

When the BS tuner 2 selects high-definition TV broadcasting, the MUSE-NTSC converter 4 supplies the MU supplied as the BS-IF signal c1 from the BS tuner 2.
The SE signal is converted into the NTSC video signal e1, and the detection result of the MUSE signal becomes valid, and the high level switching control signal f1 is supplied to the switching circuit 5 and the CRT drive circuit 7. As a result, MUSE-NT
The video signal e1 from the SC converter 4 is transferred to the switching circuit 5
Also, the color difference signal g1 and the luminance signal h1 are supplied to the CRT drive circuit 7 via the color signal reproducing circuit 6. CRT
The drive circuit 7 selects a color temperature setting unit for high-definition TV broadcasting, creates an RGB3 primary color signal from the color difference signal g1 and the luminance signal h1 from the color signal reproduction circuit 6, and based on the RGB3 primary color signal, a high-quality signal. The drive current i1 is adjusted by adjusting the color temperature using the color temperature setting unit for TV broadcasting.
Is prepared and supplied to the CRT 8. As a result, the CRT drive circuit 7 displays the RGB3 primary color signals on the CRT 8.

When the BS tuner 2 selects an NTSC television broadcast, the MUSE-NTSC converter 4 produces no MUSE signal detection result and the low level switching control signal f1 is switched to the switching circuit 5 and CRT
Supply to the drive circuit 7. As a result, the video signal d1 from the video processing circuit 3 is passed through the switching circuit 5 and the color signal reproducing circuit 6 as the color difference signal g1 and the luminance signal h1 to C.
It is supplied to the RT drive circuit 7. The CRT drive circuit 7 selects the color temperature setting unit for the NTSC system and selects R from the color difference signal g1 and the luminance signal h1 from the color signal reproduction circuit 6.
A drive current i1 is generated by creating a GB3 primary color signal and adjusting the color temperature based on the RGB3 primary color signal and using a color temperature setting unit for the NTSC system to create a CRT.
Supply to 8. As a result, the CRT drive circuit 7
The RGB primary color signals are displayed on the CRT 8.

According to such an embodiment, the NTSC television broadcast is displayed on the CRT 8 after the color temperature is adjusted by using the color temperature setting unit for the NTSC system, and the high quality TV broadcast is converted into the NTSC system. Then, the color temperature is adjusted by using the color temperature setting unit for high definition TV broadcasting, and the CRT8
Can be displayed in. Here, the high-definition TV broadcast screen is vertically compressed like the conventional screen shown in FIG. 4, but by adjusting the color temperature using the color temperature setting unit for the high-definition TV broadcast. , NTSC system has a lower color temperature than the screen. When the color temperature is lowered, the brightness of the screen is visually reduced. As a result, the television receiver of the present embodiment prevents the viewer from feeling the difference in brightness and color of the screen when the image displayed on the CRT 8 is switched from the NTSC system to the high-definition TV broadcast. Therefore, it is possible to prevent the visual quality from being deteriorated due to the difficulty of being visually perceived, the illusion that the color is changed, and the loss of sharpness of high-definition TV broadcasting.

In the embodiment shown in FIG. 1, MUSE-
The NTSC converter 4 receives M for the BS-IF signal c1.
Although the presence or absence of the USE signal is detected and the switching control signal f1 is generated, the video processing circuit uses the BS-IF signal c.
The switching control signal f1 may be generated by detecting the presence / absence of an NTSC system signal with respect to 1. Also, as a combination of a broadcasting system with an aspect ratio of 4: 3 and a broadcasting system with 16: 9, the NTSC system and MUS in satellite broadcasting are combined.
Although the C method is used, other combinations such as the PAL method and the M method are used.
A high-definition TV broadcasting system other than the USC system may be used.

[0032]

According to the present invention, even when the image displayed on the picture tube is switched to the broadcasting system having a different aspect ratio of the screen, the viewer does not feel the difference in the brightness and color of the screen. As a result, it is possible to prevent visual quality deterioration such as being difficult to see visually, the illusion that the color changes, and the loss of sharpness in high-definition TV broadcasting.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a television receiver according to the present invention.

2 is a graph of G of the color temperature setting unit of the CRT drive circuit of FIG.
FIG. 3 is a circuit diagram showing a primary color signal circuit system.

FIG. 3 is a block diagram showing a conventional television receiver.

FIG. 4 is an explanatory diagram showing an image on the television receiver of FIG.

[Explanation of symbols]

 1 Parabolic antenna 2 BS tuner 3 Video processing circuit 4 MUSE-NTSC converter 5 Switching circuit 6 Color signal reproduction circuit 7 CRT drive circuit 8 CRT

Claims (1)

[Claims] 1. A television broadcast signal of a first broadcast system is displayed on a picture tube, and a television broadcast signal of a second broadcast system having a screen aspect ratio larger than that of the first broadcast system is displayed on the screen. A tuner for displaying an intermediate frequency signal by selecting a television broadcast signal of the first and second broadcasting systems in a television receiver for displaying on a picture tube in a vertically compressed state, and the tuner. If the intermediate frequency signal from the first broadcasting system is the first broadcasting system,
A video processing circuit for converting the intermediate frequency signal from the tuner to the second broadcasting system, the intermediate frequency signal of the first broadcasting system being compressed in the vertical direction of the screen. A converter for converting into a second video signal, and a color signal for separating the first and second video signals from the converter and the video processing circuit into a luminance signal and a carrier color signal and reproducing a color difference signal from the carrier color signal. A reproduction circuit, a picture tube drive circuit for driving the picture tube in a color temperature adjustable state based on the luminance signal and the color difference signal from the color signal reproduction circuit, and an intermediate frequency signal from the tuner for the first frequency signal. Determining means for determining whether the broadcast system is the second broadcast system or the second broadcast system, and a path for supplying the first and second video signals to the color signal reproducing circuit, based on the determination result of the determining means. A switching circuit for guiding one of the first and second video signals to the color signal reproducing circuit, and a color temperature adjusting means for adjusting the color temperature of the picture tube drive circuit based on the judgment result of the judging means. A television receiver characterized in that