JPS6150481A - Television receiver - Google Patents

Abstract

PURPOSE:To provide easily a white balance adjustment for slave picture to a receiver by providing an R, G, B insertion circuit synthesizing the 1st R, G, B signal and the 2nd R, G, B signal and a pulse superimposing circuit applying a clamp pulse between the input terminal of a color difference signal and a matrix circuit. CONSTITUTION:The pulse superimposing circuit 31 is provided between capacitors 11, 12 and an input terminal for signals (R-Y) and (B-Y) except a luminance signal (-Y) in a slave picture colore difference signal. Further, a clamp pulse is fed to the pulse superimposing circuit 31 from a clamp pulse generating circuit 23. The pulse superimposing circuit consists of resistors 41, 42, 43, 44, 45, 46, a transistor 47 and capacitors 48, 49. The R-Y signal is inputted to a base of an emitter follower transistor (TR) 52 through a base and a collector of a TR51 and an output is given to one end of a capacitor 11.

Description

DETAILED DESCRIPTION OF THE INVENTION Industrial Field of Application The water valve [9] relates to a television receiver capable of simultaneously projecting two television images on one cathode ray tube screen.

Conventional configuration and problems thereof Recently, a television receiver called a so-called two-screen television has been announced. Figure 1 is a conceptual diagram of a two-screen television, where 1 is the television receiver, 2 is the main image area, and 3 is the television receiver.
is the child image section into which another TV image is reduced and inserted.

On the other hand, recent signal sources for television receivers include not only on-air broadcast signals, but also video tape recorders, video disc players, personal computers, and RGB signals of teletext broadcasting, and receivers also receive these signals. It has a connection terminal that allows you to switch modes and enjoy a variety of sources.

A conventional television receiver will be described below with reference to the drawings. In FIG. 2, RGB number inputs (R2, G2 .
B2) is the gain adjustment circuit 24 and the capacitors 13 and 14
．． 15 to the R2G, B insertion circuit 22.

- Knob 1 1 C 1 Child image section 3 of television receiver 1
Luminance signal (-Y) and color difference signal (R-Y, B-Y)
) is input to the matrix circuit 21 via capacitors 10, 11, and 12, where it is converted into an RGB signal.
1. G1. B1 signal is R, G, B insertion times Fi1122
is input. A clamp pulse is supplied to the R, G, B insertion circuit 22 from a clamp pulse generation circuit. R,
Respective outputs R3 and G3 from the G and B insertion circuits 22
, B3 are output through the DC level adjustment circuit 26, R4°G4. The B4 signal is input to the signal switching circuit 26.

The signal switching circuit 26 is supplied with the RGB signals (R5, G6°B6) of the video of the main image section 2 of the television shown in FIG. 1, and its outputs R0, Go.

The color cathode ray tube 28
added to.

Next, I will explain how this pro works.

In the case where the parent image is a personal combination, - evening output and the child image is an on-air signal output, the operation of the R, G, B insertion circuit 22 will be explained with reference to FIG. In Figure 3, (a)
is the signal waveform of R2, and (b) is the signal waveform of R1.

1 9″′y, (c)H″・“′°”9°L/
<)v ′″@6 A clamp pulse is used to clamp the noise part of R1 and R2 (generally the synchronization signal part) and adjust the DC level. (d) is a switching signal,
When the level is low, the R2 signal is output, and when the level is high, the R2 signal is output.
1 signal is obtained as output. Therefore, the insertion circuit 22
The output R3 becomes the R1 signal during the period from t=t3 to t4, and becomes the R2 signal during the other periods. Other outputs G3. Since B3 is also obtained by the same operation, the explanation will be omitted.

The signal switching circuit 26 includes the R and G3. The signal of B1 is controlled by the DC level adjustment circuit 26, and its output signal R
4, G4. B4 is added as one input signal, and the switching signal causes R5 and R4°G5 and G4 . It is controlled to output either the B6 or B4 signal. Ro,G
o, Bo is R4, G4. When the B4 signal is displayed, the personal combination 4-evening signal is displayed as the parent image on the TV screen, and the on-air signal is displayed as the child image, and R5,
G5. When switching is controlled to output the B6 signal, on-air signals and images from the VTR, camera, etc. are displayed on the TV screen as the main image section, and on-air signals are displayed on the child image section.

As described above, according to the configuration shown in FIG. 2, it is possible to realize a two-screen television for use with a personal computer, but there are major problems as described below.

In FIG. 2, R6°G5. B
Generally, the white balance of the white side and the black side of the 6 signals is adjusted in the amplifier circuit 27, and variations in the cathode ray tube 28 and circuit elements are absorbed here.

Also, R2 of personal computers, character multiplex signals, etc.
G2. In the B2 signal path, a gain adjustment circuit 24 adjusts the white side, and a DC level adjustment circuit 25 adjusts the black side, so that the white balance is adjusted on the cathode ray tube 28.

However, the signal output for the child image is the luminance signal (-Y)
It is easy to have a white balance adjustment function for the child image for two reasons: the color difference signal (R-Y, B-Y) and the need to adjust the white balance of the child image signal independently. I can't do that. In other words, in the past, the white balance of child images remained unmanaged, resulting in poor quality.

The signal output for the child image is the luminance signal (-η) and the color difference signal (R-
The reason for this is that time compression is essential in order to create a sub screen, so the RIG, B signal, or color difference signal is A/D converted, stored in memory, and then D/A again. Convert to original R, G.

B signal or luminance signal (-Y) and color difference signal (R-Y)
, B-Y), but the method of storing color difference signals is more efficient and requires less memory capacity.

The above configuration has a drawback in that it is difficult to provide a white balance adjustment function for child images.

OBJECTS OF THE INVENTION The present invention solves the above-mentioned conventional problems, and aims to provide a television receiver that can easily have a white balance adjustment function for child images.

Structure of the Invention A television receiver according to the present invention includes a matrix circuit that converts color difference signals into first R, G, and B signals, and a matrix circuit that converts color difference signals into first R, G, and B signals;
R, G, B signals and the second R, G.

An R, G, B insertion circuit that synthesizes the B signal, a clamp pulse is added to this insertion circuit, and the above color difference signal input terminal and -
1- A pulse superimposition circuit for applying the clamp pulse described above is provided between the matrix circuits, and the white balance adjustment function of the color difference signal system can be easily provided.

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

FIG. 4 is a block diagram of a television receiver according to an embodiment of the present invention. In FIG. 4, signals (RY) and (B) of the child image color difference signals excluding the luminance signal (-Y) are
A pulse superimposition circuit 31 is provided between the input terminal of -Y) and the capacitors 11 and 12. Further, a clamp pulse is applied to this pulse superimposing circuit 31 from a clamp pulse generating circuit 23. Components in FIG. 4 that have the same numbers and names as those in FIG. 2 operate in the same way, and their explanations will be omitted.

FIG. 5 shows a specific circuit example of the pulse superimposition circuit 31 shown in FIG. 4, and will be described with reference to the drawings.

The above-mentioned pulse superimposition circuit is composed of resistors 41, 42, 43, 44, 45, 46, an l-run sister 47, and a capacitor 48, 49. The RY signal is the transistor 5
1, passes through the collector, and is input to the base of the enoter follower word transistor 62, and the output is connected to one end of the capacitor 11. 53.54.65
are each resistance. Similarly, the output of the B-Y signal is added to one end of the capacitor 12.

The circuit operation will be explained with reference to FIG. When a clamp pulse of waveform (A) is input to the base of the transistor 47, waveforms (B) and (C) of opposite polarity are obtained at its emitter and collector. this
Resistors 43 and 44 are connected between the collector and emitter of one transistor 47, and a composite of waveforms (b) and (c) is obtained in the mover of each resistor. For example, when resistor 41 - resistor 42, if the movable terminal of resistor 43 is the center, the combined output will be a waveform), and if the movable terminal is the collector of transistor 47, the waveform (c) or emitter When , the waveform becomes -). A similar output is obtained at the movable terminal of the resistor 44. These outputs are connected to R via a capacitor 48 and a resistor 45.
-Y signal, and is superimposed on the B-Y signal via a capacitor 49 and a resistor 46, respectively. The R-Y signal of the collector of the transistor 61 when the movable terminal of the resistor 43 is at the center of the resistor has a waveform (), and no pulses are superimposed during the clamp period 1 = 11 to t2 and t-t6 to t7. This is the same as at 4 o'clock without the switching and pulse superimposition circuit 31, and the R-Y signal is matrixed with the luminance signal -Y using the level of the clamp period as a reference by the matrix circuit 21 in the next stage, and converted into an R signal. .

Next, when the movable terminal of the resistor 43 is at the terminal of the transistor 47, the collector R- of the transistor 61 is
The Y signal has an amplitude where the amplitude of the waveform (b) is A, and a pulse is superimposed on the RY clamp period 1=11 to t2 and 1=16 to t7. R46.

R54 is the resistance value of each resistor 46.54.

The RY signal at this time has a waveform (E). This R, -Y
The signal is matrixed with the luminance signal by the next-stage matrix circuit 21 based on the level of the clamp period. switching, t=t2 to t3 and 1= during the R-Y signal zero period
During the period from 1-16 to t6, it is a signal of 1■Δ, and during the period from 1-13 to t4, when the R-Y signal is on the positive side, it is a signal shifted by VΔ to the negative side, and during the period when the R-Y signal is on the negative side. t=t4~t6
However, since it is processed as a signal shifted by v7 to the negative side, the white balance can be adjusted to reduce the red component. Similarly, by superimposing a pulse of negative polarity on the clamp period of the RY signal, it is possible to obtain a white balance with an increased red component.

It is preferable that the resistance values of the resistors 41 and 42 be the same in view of the variable range, temperature characteristics, etc.

Effects of the Invention As described above, according to the present invention, the child image white balance adjustment function can be provided at the time of the color difference signal in the previous stage that does not affect other signal systems, so the white balance of the child image can be adjusted independently. The excellent effect of being adjustable can be obtained.

[Brief explanation of drawings]

Fig. 1 is a conceptual diagram of a two-screen television, Fig. 2 is a block diagram showing the configuration of a conventional television receiver, Fig. 3 is a waveform diagram for explaining the operation of the receiver shown in Fig. 2, and Fig. 4. 6 is a block diagram showing the configuration of a television receiver according to an embodiment of the present invention, FIG. 6 is a circuit diagram of a specific circuit example of the pulse superimposition circuit in the receiver of FIG. 4, and FIG. FIG. 2 is a waveform diagram for explaining the operation of FIG. 1... Television receiver, 2... Parent image section. 3... Child image section, R1, G1, B1...
...First I RGB signal, R2, G
2. B2...Second RGB signal, 21...
・Matrix circuit, 22...R,G. B insertion circuit, 23... 2-amp pulse generation circuit, 31... pulse superimposition circuit. Name of agent: Patent attorney Toshio Nakao and 16 others Figure 3 Figure 4-Y R-V δ-Y Figure 5

Claims (1)

[Claims] A matrix circuit that converts the color difference signal and the luminance signal into first R, G, B signals, and R, G, B that synthesizes the first R, G, B signals and the second R, G, B signals. A television receiver comprising: an insertion circuit; and a pulse superimposition circuit that applies a clamp pulse to the insertion circuit and applies the clamp pulse between the input terminal of the color difference signal and the matrix circuit.