JPH02250587A - Matrix circuit and interchangeable television receiver - Google Patents

Abstract

PURPOSE:To simplify a circuit by commonly using a matrix circuit and a picture quality correcting circuit for an NTSC signal and for a Multiple Sub-Nyquist Sampling Encoding(MUSE) signal. CONSTITUTION:A matrix circuit 24 can execute a matrix processings for the NTSC signal and for the MUSE signal, and it can be shared by the NTSC signal and the MUSE signal. Only by providing a picture quality circuit 22 on the front stage of the matrix circuit, the circuits 22 and 24 can be shared by the NTSC signal and the MUSE signal. Thus since the matrix circuit 24 and the picture quality circuit 22 can be used in common by the NTSC signal and the MUSE signal, the circuit can be simplified.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention provides a matrix circuit suitable for a television receiver compatible with the NTSC system and high-definition television system, and employs this matrix circuit. Regarding compatible television receivers.

(Prior Art) Currently, NTSC television broadcasting is being carried out in Japan, and high-definition television broadcasting on a large screen is about to begin. In this high-definition television broadcasting, M is used as a band compression technology.
US E (Multiple Sub-NVQUi
By developing the St 5 Alt) tin (l Encodina) system, it is now possible to broadcast via satellite. In order to receive a high-definition television broadcast signal (MUSE signal), a satellite broadcast reception tuner, a MUSE decoder, and a high-definition television broadcast monitor are required. However, when considering the prevalence of NTSC television receivers, it is possible to adopt a down converter that converts MLJSE signals to NTSC signals and receive high-definition television broadcasts with NTSC television receivers. It is thought that this system will be used for boat fishing in the future.

FIG. 3 is a block diagram showing a conventional compatible television receiver capable of receiving both MLJSE and NTSC signals.

The NTSC signal induced in antenna 1 is transmitted to NTSC receiver W.
It is input to i2. NTSC reception%! The i-2 selectively receives the NTSC signal of a predetermined channel and outputs it to the NTSC signal processing circuit 3. The NTSC signal processing circuit 3 performs video processing on the received NTSC signal and generates a luminance signal @ (Y signal).
and color difference signals (RY multiplied signal and BY signal) are output to the matrix circuit 4. The matrix circuit 4 performs matrix processing on these luminance signals and color difference signals so that +qt:r<,
a.

The B signal is given to the switching circuit 5. On the other hand, the MUSE signal induced in the parabolic antenna 6 for transmitting and receiving signals from the BS
The signal is input to tuner 7. BS nayuna 7 selectively receives MUSE signals of predetermined channels and outputs them to MUSE down converter 8 . The MUSE down converter 8 converts the MUSE signal into an NTSC signal and converts it into a luminance signal (
Matrix circuit 9
outputs R, G, and B signals obtained by matrix processing these luminance signals and color difference signals to the switching circuit 5. The switching circuit 5 selects the R, G, and B signals from the matrix circuit 4 or the matrix circuit 9 and sends them to the picture tube drive circuit 10.
is giving to In this way, the receiving lIl tube drive circuit 10
gives R, G, B signals to the cathode of c RT 11,
NTSC broadcast or high-definition broadcast video is displayed on the screen. Note that in this system, even high-definition broadcasting has the same screen quality as NTSC broadcasting.

By the way, the MUSE down converter 8 does not convert the matrix coefficients when converting the MUSE signal to an NTSC signal. For this reason, the matrix circuits 4.9 perform matrix operations using mutually different matrix coefficients. That is, the matrix circuit 4 for NTSC signals inputs the Y signal, the RY signal, and the BY signal, and performs the matrix operation shown by the following equation (1) to obtain the R, G, and B signals.

On the other hand, the matrix circuit 9 for the MUSE signal receives the YM multiplied signal R-YM multiplied signal and B-YM multiplied signal, and performs the matrix operation shown in the following equation (2) to obtain R, G, and B signals. .

Due to the difference in matrix coefficients shown in equations (1) and (2) above, it was necessary to provide separate matrix circuits for the NTSC signal and the MUSE signal. Furthermore, since the matrix circuit is individually provided, an image quality correction circuit must also be provided separately.

FIG. 4 is a block diagram showing the image quality correction circuit.

A luminance signal (Y signal) is inputted to the input terminal 12, and color difference signals RY signal and BY signal are inputted to input terminals 13 and 14, respectively. The Y signal from the input terminal 12 is applied to an aperture control circuit 15. The aperture control circuit 15 performs a horizontal peaking operation,
The horizontal contour of the Y signal is emphasized and output to the black expansion circuit 16. The black expansion circuit 16 adjusts the gain on the black level side of the Y signal to emphasize sharpness in dark areas of the picture and supplies it to the gamma correction circuit 17. The gamma correction circuit 17 performs nonlinear processing on the Y signal, suppresses the white peak signal, improves color development, and outputs the signal to the matrix circuit 18. Further, the speed modulation circuit 19 uses the Y signal from the input terminal 12 to
The horizontal scanning speed of the CRT is changed depending on the picture to correct the horizontal contour. On the other hand, R from input terminals 13.14
The -Y signal and the BY signal are provided to the matrix circuit 18 via delay circuits 20 and 21, respectively. As a result, the R-Y signal and the B-Y signal are transferred to the matrix circuit 18 with the same delay amount as the delay m of the Y signal caused by the aperture control circuit 15, black expansion circuit 16, and gamma correction circuit 11.
is given to.

In this way, image quality correction is performed by adjusting only the Y signal. In order to adjust the Y signal, it is necessary to provide an image quality correction circuit before the matrix circuit 4.9. Therefore, matrix circuit 4 for NTSC signals and ML
It was necessary to provide a separate image quality correction circuit upstream of the JSE signal matrix circuit 9.

As described above, in the above-mentioned example, it is necessary to provide separate matrix circuits and image quality correction circuits for NTSC Shintan and MIJSE signals, which poses a problem in that the circuit scale becomes extremely large.

(Problems to be Solved by the Invention) As described above, in the conventional compatible television receiver described above, the matrix circuit and the image quality correction circuit are
It is necessary to provide separate ones for signals and MUSE signals,
There was a problem that the circuit scale became large.

The present invention has been made in view of such problems, and includes:
Matrix circuit and image quality correction circuit for NTSC signal and M
It is an object of the present invention to provide a matrix circuit and a compatible television receiver that can reduce the circuit scale by making it possible to use the same for LJSE signals.

[Structure of the Invention] (Means for Solving the Problems) A matrix circuit according to the present invention includes a first voltage dividing means for dividing a luminance signal at a predetermined voltage dividing ratio, and a first voltage dividing means for dividing a luminance signal at a predetermined voltage dividing ratio;
a second pressure dividing means that divides the pressure at the same partial pressure ratio as the partial pressure ratio of the first pressure dividing means; a third voltage dividing means capable of dividing the BY signal by a pressure ratio; a dividing ratio switching means for switching the dividing ratio of the third voltage dividing means; and an output of the second and third voltage dividing means. a synthesizing means which obtains a G-Y signal by adding at a predetermined ratio, the outputs of the second and third voltage dividing means, and the difference between the output of the synthesizing means and the output of the first voltage dividing means. The compatible television receiver according to the present invention is equipped with a differential amplifier that obtains R, G, and B signals by respectively determining the R, G, and B signals. A signal processing circuit and M
a MULE down converter that converts the USE signal into an NTSC signal and outputs a luminance signal and a color difference signal;
a switching circuit that selectively outputs the outputs of the SC signal processing circuit and the MLJSE down converter based on a switching signal;
a matrix circuit that has matrix coefficients for the NTSC signal and matrix coefficients for the MUSE signal and operates by switching these matrix coefficients based on the switching signal; and a matrix circuit that corrects the image quality of the luminance signal from the switching circuit to The image quality correction circuit is provided with an image quality correction circuit that applies to the matrix circuit.

(Function) In the matrix circuit of the present invention, the synthesizing means adds the outputs of the second and third voltage dividing means at a predetermined ratio to generate G-Y
I'm getting a signal. Therefore, the partial pressure ratio switching means makes the partial pressure ratio of the third pressure dividing means the same as the partial pressure ratios of the first and second pressure dividing means, or makes the matrix coefficient approximately 1.25 times these partial pressure ratios. By changing 1. NTSC
Matrix processing can be performed for both signals and MUSE signals. Further, in the compatible television receiver of the present invention, the switching circuit selects between the luminance signal and color difference signal from the NTSC signal processing circuit and the r41 degree signal and color difference signal from the MULE down converter based on the switching signal. and output it. In addition, this switching signal switches the matrix coefficients of the matrix circuit, and the matrix circuit receives the luminance signal and color difference signal from the NTSC signal processing circuit, or the luminance signal and color difference signal from the MUSE down converter. Zu, R, G, B
I can get a signal. The image quality correction circuit can be installed before the matrix circuit, so the matrix circuit can be
Since it is shared for SC signals and MUSE signals,
The image quality correction circuit can also be shared between the NTSC signal and the MUSE signal.

(Example) Hereinafter, an example of the present invention will be described in detail based on the drawings. FIG. 1 is a block diagram showing an embodiment of a compatible television receiver according to the present invention.

Components in FIG. 1 that are the same as those in FIG. 3 are given the same reference numerals.

Antenna 1, reception@route 2, NTSC (lffi logic circuit 3)
, parabolic amplifier 6, BS tuner 7, MUSE down converter 8, picture tube drive circuit 10, CRTll
, the configurations of the speed modulation circuit 19 and the delay circuits 20 and 21 are the same as those of the prior art.

In this embodiment, Y from the NTSC signal processing circuit 3 is
signal, R-Y signal, B-Y signal, YM times signal R from MUSE down converter 8, -YM times signal and B-Y
The M-fold signal is input to the switching circuit 23. Switching circuit 2
3 is controlled by a switching signal input to the terminal 25,
NTSC signal processing circuit 3 and MUSE down converter 8
The output is selected and output. That is, when a high level (hereinafter referred to as 'H') switching signal is input to the terminal 25, the switching circuit 23 supplies the Y signal of the NTSC signal processing circuit 3 to the speed modulation circuit 19 and the image quality circuit 22, and multiplies the RY The signal and the B-Y signal are respectively applied to delay circuits 20 and 21. On the other hand, a low level (hereinafter referred to as "L") is applied to the terminal 25.
When the switching signal of MLJSE is input, the switching circuit 23
The YM times signal is applied to the speed modulation circuit 19 and the image quality circuit 22 of the down converter 8, and the R-YM times signal and the B-YM times signal are applied to delay circuits 20 and 21, respectively. The image quality circuit 22 is the aperture control circuit 1 in FIG.
5. It is composed of a black expansion circuit 16 and a gamma correction circuit 17. The luminance signal from the image quality circuit 22 and the color difference signal from the delay circuits 20 and 21 are sent to the matrix circuit 24.
is input. The matrix circuit 24 has a control input terminal 26
The matrix coefficients are switched by a switching signal from a terminal 25 that is input to the terminal 25. The matrix circuit 24 outputs R, G, and B signals to the picture tube drive circuit 10.

FIG. 2 is a circuit diagram showing a specific configuration of the matrix circuit 24. As shown in FIG.

The input terminal 27 receives the Y signal or the YM multiplied signal from the image quality circuit 22, and the input terminal 28 receives the R-Y signal from the delay circuit 20.
A signal or an R-YM multiplied signal is input, and a large BY signal or a B-YM signal is input from the delay circuit 21 to the input terminal 29. The input terminal 27 is connected to the reference potential point via resistors R1 and R2, and the connection point of the resistors R1 and R2 is connected to the amplifier Q.
Connected to the inverted end of 1. The non-inverting end of amplifier Q1 is connected to the reference potential point, and the output end is connected to amplifier Q2,
Connected to the inverted ends of Q3 and Q4.

The input terminal 28 is connected to a reference potential point via resistors R3 and R4, and the connection point between the resistors R3 and R4 is connected to the non-inverting end of the amplifier Q2. In addition, the input terminal 29 is connected to the reference potential heat via the resistors R5, Re and the collector-emitter path of the transistor Tr3.
The connection point of R6 is connected to the inverting end of amplifier Q4.

Furthermore, the connection point of resistors R3 and R4 and the resistor 1” (5, R6
The connection points of are connected to the bases of transistors Trl and Tr2, respectively. The transistors Trl and Tr2 form a differential pair, and their collectors are commonly connected and connected to a reference potential point via a resistor R7, as well as to the non-inverting end of an amplifier Q3. The emitter of the transistor Tr1 is connected to the power supply terminal 30 through a resistor R8, and the emitter of the transistor Tr2 is connected to the power supply terminal 30 through a resistor R9. The output terminals of the amplifiers Q2°R3 and R4 are connected to output terminals 31, 32, and 33, respectively. Note that the voltage division ratio by resistors R1 and R2, the voltage division ratio by resistors R3 and R4, and the voltage division ratio by resistors R5° and R6 are all 0.8 (
--) is set to 1.25. Furthermore, the resistances of resistors R7 to R9 are as follows:
The operation of the embodiment configured in this way will be explained.

As shown in equations (1) and (2) above, the matrix coefficients of the line axis and front axis are different between the MUSE signal and the NTSC signal. Now, the matrix coefficient on the BY axis in equation (1) representing the matrix operation for NTSC signals is multiplied by 1.25. As a result, the following formula (3) is obtained.

This equation (3) and the above equation (2) differ only slightly in the linear axis coefficient (+2% for the R-Y axis, -4% for the B-Y axis), and in practice, the equation (3) A matrix circuit having matrix coefficients shown in can be used for the MLJSE signal.

Now, if you want to receive NTSC broadcasting, connect " to terminal 25.
Input HH switching ■). Then, switching circuit 2
3 outputs Y, RY, and BY signals. The transistor Tr3 of the matrix circuit 24 is turned on when ``1'' is applied to its base via the control input terminal 26.

As a result, the BY signal input via the input terminal 29 is divided by the resistors R5 and R6 and applied to the non-inverting end of the amplifier Q4.

Further, the Y signal input to the input terminal 27 is connected to the resistor R1,
The voltage is divided by R2 and applied to the non-inverting ends of amplifiers Q2 to Q4 via amplifier Q1. The RY signal input to the input terminal 28 is divided by resistors R3 and R4 and applied to the non-inverting end of the amplifier Q2. The voltage division ratios of resistors R1, R2, resistors R3, R4, and resistors R5, R6 are all 0.
8, the RY signal and the BY signal are multiplied by 0.8 and applied to the non-inverting ends of the amplifiers Q2 and R4, respectively. The non-inverting terminal inputs of the amplifiers Q2 and R4 are also applied to the bases of the transistors Trl and Tr2. A signal appearing at the common collector of transistors Trl and Tr2 is expressed by the following equation (4).

--0,8 (RY) 0.51-0.8 (B-Y)
0.19-0.8 (G-Y)
...(4) This 0.8 (G-Y) is amplifier Q3
is given at the non-inverting end of . Each of the amplifiers Q2 to Q4 outputs the difference between the input signals at the non-inverting end and the inverting end. That is,
From amplifier Q2, 0.8R(-0,8(R-Y)-(-
0.8Y)) is output, and 0.8G is output from amplifier Q3.
(-0,8(G-Y)-(-〇,8Y)) is output,
From amplifier Q4 0.8B (=0゜8 (B-Y)-
(-0,8Y)) is output.

The matrix processing of the matrix circuit 24 described above can be expressed as the following equation (5).

(5) As shown in equation (5) above, when the HII switching signal is input to the terminal 25, the matrix circuit 24
It can be seen that matrix processing shown in equation 1), that is, matrix processing for NTSC signals is performed. Note that the level of the primary color signal decreases (0.8 times).

On the other hand, when receiving high-definition broadcasting, connect L to terminal 25.
Input the switching signal of II. In this case, switching circuit 2
3 is for YM, R-YM, B-YM and other signal outputs. The YM signal is 0.8 at the inverting ends of amplifiers Q2 to Q4.
It is given multiplied. Further, the R-YM multiplied signal is multiplied by 0.8 and applied to the non-inverting end of the amplifier Q2. The transistor Tr3 has a base connected to it via a control input terminal 26.
is applied and off. Therefore, the B-YM multiplied signal from the input terminal 29 is applied to the non-inverting end of the amplifier Q4 without being voltage-divided.

A signal expressed by the following equation (6) is applied from the common collector of the transistors Trl and Tr2 to the non-inverting end of the amplifier Q3.

=-0,8(R-YM)xO,51-1(B-
YM ) xO, 19...(6) Therefore, the following (
7) Equation is derived.

-0,8 (R-YM) xo, 51 -0.8 (B-YM) Xl, 25X0.19-
-0.8 (R-YM) Xo, 51-0.8 (B
-YM) xo, 2375-0.8 (G-YM
)...(7) Amplifiers Q2 to Q4 are
By finding the difference between the inputs at the non-inverting end and the inverting end, R
, G, B signals are obtained. Matrix circuit 24 described above
The matrix processing of is shown in the following equation (8).

... (8) From the comparison between equation (8) and equation (2), it can be seen that 71
When a switching signal of 11+ is given, matrix circuit 2
It can be seen that matrix operation for the MUSE signal is possible in No. 4.

The receiving circuit 2 selects the NTSC signal induced in the antenna 1 and provides it to the NTSC signal processing circuit 3, and the NTSC signal processing circuit 3 outputs Y, R-Y, and B-Y signals to the switching circuit 23. On the other hand, the 88 tuner 7 tunes the MUSE signal induced in the parabolic antenna 6 and supplies it to the MUSE down converter 8 .

MUSE down converter 8 converts the MULE signal to NTSC
It converts it into a signal and outputs it to the YM, R-YM, and B-YM multiplied signal switching circuit 23. Now, H' is applied to terminal 25.
gives a switching signal. Then, the switching circuit 23 becomes NT
Y, R-Y from the SC signal processing circuit.

The matrix circuit 24 selects and outputs the B-Y signal.
Performs matrix processing of TSC signals. The image quality of the Y signal from the switching circuit 23 is corrected by the image quality circuit 22, and the matrix circuit 24 performs matrix processing to
, B signals to the picture tube drive circuit 10. In this way, NTSC broadcasting can be displayed on the CRTII. On the other hand, when an “L” switching signal is applied to the terminal 25, the switching circuit 23
, R-YM, B-YM multiplied signal is selected and output,
The matrix circuit 24 performs matrix processing of the MUSE signal. The image quality of the YM multiplied signal from the switch 23 is corrected by the image quality circuit 22, and the matrix circuit 24 performs matrix processing shown in equation (8) and outputs R, G, and B signals to the picture tube drive circuit 10. In this way, high quality broadcasting can be displayed on the CRTll.

In this way, in this embodiment, the matrix circuit 24
is capable of matrix processing for NTSC signals and matrix processing for MUSE signals.
It can be shared with the LE signal. As described above, the image quality circuit 22 may be provided at the front stage of the matrix circuit, and can be used for both the NTSC signal and the MULE signal.

[Advantageous Effects of the Invention 1] As described above, according to the present invention, the matrix circuit and the image quality correction circuit can be used in common for NTSC signals and MLJSE signals, so the circuit can be simplified.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of a compatible television receiver according to the present invention, FIG. 2 is a circuit diagram showing a specific configuration of the matrix circuit 24, and FIG. 3 is a conventional compatible television receiver. FIG. 4 is a block diagram showing the image quality correction circuit. 3... NTSC signal processing circuit, 8... MUSE down converter, 22... image quality circuit, 23... switching circuit, 24... matrix circuit,
25...terminal, 26...control input terminal, R1-R9
...Resistance, Trl~Tr3...Transistor, 01
~Q4...Amplifier.

Claims (2)

[Claims] (1) A first voltage dividing means that divides the luminance signal at a predetermined voltage dividing ratio; and a second voltage dividing means that divides the RY signal at the same voltage dividing ratio as the first voltage dividing means. and a third voltage dividing means capable of dividing the BY signal at the same partial pressure ratio as that of the first voltage dividing means and approximately 1.25 times this partial pressure ratio, and this third voltage dividing means. a dividing means for switching the dividing ratio of the third voltage dividing means; a synthesizing means for adding the outputs of the second and third voltage dividing means at a predetermined ratio to obtain a G-Y signal; R, G
, and a differential amplifier for obtaining a B signal. (2) an NTSC signal processing circuit that outputs a luminance signal and a color difference signal obtained from an NTSC signal; a MUSE down converter that converts a MUSE signal into an NTSC signal and outputs a luminance signal and a color difference signal; the NTSC signal processing circuit; a switching circuit that selectively outputs the output of the MUSE down converter based on a switching signal; and a matrix coefficient for the NTSC signal and a matrix coefficient for the MUSE signal, and switches these matrix coefficients based on the switching signal. What is claimed is: 1. A compatible television receiver comprising: a matrix circuit that operates in accordance with the switching circuit; and an image quality correction circuit that corrects the image quality of a luminance signal from the switching circuit and provides the corrected image quality signal to the matrix circuit.