JPS6376596A - Television signal processing circuit - Google Patents

Abstract

PURPOSE:To improve the quality of a reception picture by controlling the amplitude of the higher frequency components of a composite color TV signal while including the higher components of an illuminance signal, as well, thereby separating the components to a carrier color signal and an illuminance signal. CONSTITUTION:A Y/C separation circuit 2 separates the output of an adding circuit 20, i.e., a TV signal to which the amplitude of higher components is controlled, into an illuminance signal and a carrier color signal, and the former signal is outputted to an illuminance signal output terminal 3 and the latter signal to the color signal input terminal 25 of a chrominance signal saturation adjusting circuit(SC) 24. The chrominance signal saturation adjusting circuit 24. When the input signal to its input terminal 1 is a color TV signal, adjusts the gain for the carrier chrominance signal from the input terminal 25 by using a saturation designating signal supplied to a saturation adjustment input terminal 16 so that the thickness of a color on the display screen comes to be as designated, and outputs the signal to a carrier chrominance signal output terminal 7. Accordingly, if the input is a color TV signal, since its higher components is controlled of its amplitude to a suitable value by a chrominance signal amplitude control circuit 14 with the color burst for reference and supplied to Y/C separation circuit, the higher components of an illuminance signal is controlled in a suitable amplitude.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a television signal processing circuit, and in particular, to a television signal processing circuit that inputs a composite color television signal, corrects its frequency characteristics, and separates it into a luminance signal and a carrier color signal. The present invention relates to a television signal processing circuit.

[Conventional technology]

Conventionally, a television signal processing circuit that separates a composite color television signal used in television receivers and the like into a luminance signal and a carrier color signal has been developed, for example, by F Gendai Color Television Technology (Ohmsha, 1930).
4), pages 64 and 129, the basic configuration shown in Figure 2 is adopted. In FIG. 2, a television signal input terminal 1, which is connected to the video detection output of a television receiver or the reproduction output of a video tape recorder, is connected to a luminance signal color signal separation (Y/C separation) circuit 2. . The Y/C separation circuit 2 separates the input television signal from the input terminal 1 into a luminance (Y) signal and a carrier color (C) signal using a frequency separation means or the like, and outputs the former to the luminance signal output terminal 3 and the latter to the luminance signal output terminal 3. It is output to the color signal input terminal 5 of the color signal amplitude control adjustment circuit 4.

The color signal amplitude control adjustment circuit 4 checks whether there is a color burst in the carrier color signal at the input terminal 5, and if there is a color burst, the amplitude of the color burst is set to the reference value according to the reference value at the saturation setting reference input terminal 6. The gain for the carrier color signal is adjusted to the value specified by the value, and the carrier color signal with the adjusted gain is output to the carrier color signal output terminal 7. When there is no color burst, that is, when the input television signal is not a composite color television signal but a monochrome television signal, the color signal amplitude control adjustment circuit 4 sets the gain for the carrier color signal to zero and adjusts the gain to the carrier color signal. Noise is prevented from being transmitted to the output terminal 7, and the band limit imposed on the luminance signal for Y/C separation is canceled through the color burst presence/absence signal terminal 8 connected to the YC separation circuit 2.

[Problem that the invention seeks to solve]

The above-mentioned conventional technology has a drawback in that it is not possible to faithfully reproduce narrow patterns on a television screen because the amplitude of the high-frequency component of the luminance signal is not controlled. That is, in the configuration of FIG. 2, as is clear from the above explanation, the amplitude of the carrier color signal at the output terminal 7 is controlled based on the amplitude of the color burst, but the amplitude of the luminance signal at the output terminal 3 is controlled. It has not been. Therefore, if the TV signal at input terminal 1 is a color TV signal and its high frequency components have a relative deviation from the low frequency components (for example, in the receiver, there is a mismatch in the antenna system and resonance occurs. ), the amplitude of the carrier color signal at output terminal 7 becomes a predetermined value;
In the luminance signal, the high frequency component remains with an amplitude deviation from the low frequency component.

Therefore, the purpose of the present invention is to eliminate the drawbacks of the above-mentioned conventional examples,
An object of the present invention is to provide a television signal processing circuit that can also control the amplitude of high-frequency components of a luminance signal when the input signal is a color television signal.

[Means for solving the problem] In order to achieve the above object, the present invention separates a high frequency component including a carrier color signal from an input composite color television signal,
controlling the amplitude of the high frequency component with reference to the amplitude of the color burst, and converting the amplitude controlled high frequency component to at least the low frequency component of the input composite color television signal separated from the input composite color television signal. The amplitude is controlled so that the amplitude of the color burst of the added signal becomes a normal value, and the luminance signal and the carrier color signal are separated from the added signal.

[Effect]

In the above configuration, the gain control means controls the gain of the high frequency component of the input signal including the high frequency component of the luminance signal and the carrier color signal, and the gain of the high frequency component of the input signal including the high frequency component of the luminance signal and the carrier color signal is Since the separation is performed, the amplitude of the high frequency component of the luminance signal is also controlled to a predetermined value, and the drawbacks of the prior art are eliminated.

〔Example〕

The present invention will be explained in detail below.

FIG. 1 is a diagram showing the basic configuration of an embodiment of the present invention. In FIG. 1, the TV signal input terminal 1 has a low frequency range (
L) High frequency (G) is input to the separation circuit 9. The low and high frequency separation circuit 9 separates the television signal at the input terminal 1 into a high frequency component including the carrier color signal and a low frequency component other than the carrier color signal, and outputs the latter to the low frequency output terminal 13 and the former to the high frequency output terminal. Output to 15.

The low and high frequency separation circuit 9 is a so-called demultiplexer, and can be realized using an LC filter, an active filter, a digital filter, etc. The gain of the separation circuit 9 at the color subcarrier frequency is Although it is desirable for the output terminal 13 to be 0 and the high frequency output terminal 15 to be 1, this is not an essential condition as it can be corrected later with amplitude control, etc.Next, the high frequency output terminal 15 is set to 1 for color signal amplitude control. Circuit (ACC)
14.

The color signal amplitude control circuit 14 outputs the signal from the terminal 15 to the signal output terminal 1 when the signal at the input terminal 1 is a color TV (No.
The gain up to 7 is controlled so that the amplitude of the color burst of the sum signal of terminals 13 and 17 becomes a normal value. The low frequency component at the terminal 13 and the high frequency component whose amplitude has been controlled at the terminal 17 are added by the adder circuit 2o to form the Y/C chick shunt circuit 2 output. The color signal amplitude control circuit 14 further sets the gain of the color signal amplitude control circuit 14 to a specific value (usually 1) when a color burst cannot be detected because the signal at the input terminal 1 is a black and white television signal. and control other circuits through the color burst presence/absence signal terminal 18.

The output of the Y/C branch circuit 2 addition circuit 20, that is,
The television signal with the amplitude of the high frequency component controlled is separated into a brightness signal and a carrier color signal, and the former is sent to the brightness signal output terminal 3 and the latter is sent to the color signal input terminal 25 of the color signal saturation adjustment circuit (SC) 24. Output.

The Y/C separation circuit 2 performs simple frequency separation (separation of the carrier color signal using a bandpass filter having a pass band centered on the color subcarrier, separation of the luminance signal using a notch filter that suppresses frequencies near the color printing carrier wave frequency), Separation using the sum difference of signals between scanning lines (separation using a so-called comb filter)
Conventionally known separation circuits such as 1) and separation using a combination of differences between frames can be used. When the input signal at the input terminal 1 is a color television signal, the color 4Z-i'T saturation level 1 checking circuit 24 adjusts the color signal for the carrier color signal at the input terminal 25 using the saturation level designation signal applied to the saturation level adjustment input terminal 1G. The gain is adjusted so that the color density on both sides of the display becomes as specified and output to the carrier color signal output terminal 7. If a color burst cannot be detected because the input signal is a black and white television signal, etc., the color signal saturation adjustment circuit 24 uses the signal from the color burst presence/absence signal terminal 18 of the color signal amplitude control circuit 14 to detect the color burst at the input terminal 25. Transmission of the carrier color signal from the carrier color signal output terminal 7 to the carrier color signal output terminal 7 is cut off. Manny, Y/C separation circuit 2 also has color burst presence/absence signal terminal 1
With the signal from 8, the band limit imposed on the g signal by 9 is lifted.

As explained above, according to the configuration shown in FIG. 1, if the input television signal is a color television signal, the high frequency components of the input television signal are converted to color burst based on the color signal distribution system 'JJ circuit 14. The amplitude is controlled to an appropriate value and Y/C
Since the high frequency component of the brightness signal at the brightness signal output terminal 3 is fed to the separation circuit, the high frequency component is controlled to have an appropriate amplitude.

Note that the configuration shown in FIG. 1 can be modified as follows within the spirit of the present invention. That is, the signal at the input terminal 1 is directly outputted to the low-frequency output terminal 13 without performing low-frequency separation by the low-frequency high-frequency separation circuit 9. In this case, the color signal amplitude control circuit 14 needs to control the gain from the input terminal 15 to the output terminal 17 in both the positive and negative ranges. Therefore, the color signal amplitude control circuit 14 is somewhat more complex than the configuration shown in FIG.

Further, linear deformation is also possible. That is, the carrier color signals are not separated from the output of the adder circuit 20, but directly from the output terminal 17 of the color signal control circuit 14.

Next, a specific configuration of an embodiment of the present invention will be explained with reference to FIG. FIG. 3 shows an example in which the basic configuration of FIG. 1 is realized by digital processing, and is a configuration suitable for a digital high-definition television receiver. In FIG. 3, the television signal input terminal 1 is connected to an AD converter 11, and the AD converter 11 converts the television signal at the input terminal 1 into a digital signal and converts it into a digital low-high frequency separation circuit 19. give to The sampling (clock) frequency for digitization and subsequent digital processing is determined by the digital processing method, but in the following explanation we will assume that the input television signal is an NTSC signal, which is considered to be the most suitable. 4 times the color subcarrier (14,32 MHz
).

In the low frequency and high frequency separation circuit 19, the digital input television signal from the AD converter 11 is first supplied to a delay circuit 101, and further supplied to a delay circuit 102 through the delay circuit 101. The delay circuits 101 and 102 are circuits that delay an input signal by two clock cycles, and can be configured with two-stage connected registers or the like. The input and output of the delay circuit 101 are added by an adder circuit 103, the input and output of the delay circuit 102 are added by an adder circuit 104, and the adder circuits 103 and 10
The outputs of 4 are added by an adder circuit 105. The output of the adder circuit 105 is divided into four by the coefficient unit 106,
It is output to the low frequency output terminal 13 and becomes a low frequency component output. The output of the coefficient multiplier 106 is also subtracted from the output of the delay circuit 101 by a subtraction circuit 107. The output of the subtracter 107 is output to the high frequency output terminal 15 and becomes a high frequency component output.

With the configuration described here, the input and output terminals 13 and 15 of the low frequency and high frequency separation circuit 19 each constitute a -2 router with a tap interval of 2 clock periods and a tap gain of -2.

Therefore, the frequency gain characteristic of the separation circuit 19 is as shown in FIG. That is, the gain to the low-frequency output terminal 13 is 1 for direct current and 3 for the color subcarrier, as shown by the solid line 401.
．． It has zero gain between 58 and 1 Hz. High frequency output terminal 1
The gain to 5 is zero at DC, as shown by the dotted line 402, and the gain to 3
．． It becomes 1 at 58MHz. In Figure 4, 7,
At 16 MHz, the gain to the low frequency output terminal 13 is 1, and the gain to the high frequency output terminal 15 is 1, but since the TV signal band is 5 MHz or less, it is used as a high frequency and low frequency separation. There is no inconvenience.

The high frequency component signal from the high frequency output terminal 15 from the low frequency/high frequency separation circuit 19 is applied to one input terminal of the multiplication circuit 109 of the one color signal amplitude control circuit 14. Color signal amplitude adjustment circuit 14
uses the output of the multiplication circuit 109 as the signal output terminal 17, and further includes the following circuit.

That is, the output of the multiplication circuit 109 is connected to both inputs of the multiplication circuit 111 that constitutes the square circuit 110. The squaring circuit 110 can also be constructed using a read-only memory (ROM).

Note that since the input amplitude range of the square circuit 110 may be somewhat larger than the normal amplitude of the color burst, it is possible to make the number of bits smaller than other multiplication circuits and addition circuits.

The output of the squaring circuit 110 is delayed by a one-clock cycle delay circuit 1/2 and is added to the output by an adder circuit 113. The output of the adder circuit 113 is the sum of the squares of two consecutive samples of the signal at the output terminal 17, and since the sampling frequency is four times the color subcarrier, if the signal at the output terminal 17 is a carrier color signal, then , is equal to the square of the carrier color signal. The output of the adder circuit 113 is subtracted by a subtracter circuit 115 from the value of the square of the normal amplitude of the color burst applied to the burst reference amplitude terminal 114, and is applied to the integration circuit 117 through a switch 116. The integrating circuit 17 outputs the output of the switch 116 only during the period when a color burst exists, which is indicated by the signal at the burst sampling signal terminal 118.
That is, if the switch 116 is on, the difference between the square of the normal amplitude of the color burst and the square of the amplitude of the color burst at the output terminal 17 is integrated. The integration output terminal 119 of the integration circuit 117 becomes the other input of the multiplication circuit 109,
The gain from the high frequency output terminal 15 to the signal output terminal 17 is controlled.

With the configuration described so far, when the switch 116 is on, the amplitude of the color burst at the signal output terminal 17 is controlled to be the normal amplitude by negative feedback,
The color subcarrier and the high frequency components of the luminance signal are output to the signal output terminal 17.
to the appropriate amplitude.

Other components of the color signal amplitude control circuit 14 are for providing additional control. First, the comparator circuit 120 finds the difference between the square of the normal amplitude of the burst at the adder circuit 115 and the square of the burst amplitude at the terminal 17 using the signal at the burst sampling signal terminal 118, and the absolute value of the difference is determined to be within a certain limit. When the value of the difference becomes smaller, the switch 116 is turned off so that the value of the output terminal 119 of the integrator 117 remains at the value at that time, and the absolute value of the difference is set to another fixed limit larger than the fixed limit. Switch 1 when exceeded
16 is turned on. This control may be difficult to achieve in the short term due to the effects of noise and quantization caused by digitalization.
This is to prevent the gain of the color signal amplitude control circuit 14 from fluctuating due to fluctuations in the output of the color signal amplitude control circuit 19, thereby preventing screen unevenness from occurring.

Next, another comparator circuit 121 compares the value of the integrator output terminal 119 with a certain limit, and when it becomes larger than this limit, the value of the integrator output terminal 119 is changed to a value smaller than the limit (from the terminal 15). The integrating circuit 117 is controlled so as to fix the gain to 17 at a value of approximately 1. Comparison circuit 121
Corresponding to the addition circuit 1, the other comparison circuit 122
The value of the square of the amplitude of the color burst at the terminal 17 is found from the output of the output terminal 13 using the signal at the burst sampling signal terminal 118, and when this value becomes larger than a predetermined limit, the output value of the integrating circuit output terminal 119 is determined. Unfix,
The integrating circuit 117 is restored to normal operation. The color signal amplitude control circuit 14 uses the comparison circuits 121 and 122 to
When a color burst cannot be detected because the signal at the input terminal 1 is a black and white television signal, the high frequency component at the terminal 15 is output as is to the terminal 17. Furthermore, the integrating circuit 117 has an integrating circuit output terminal 119
A signal indicating whether or not the output is fixed is output to the color burst presence/absence signal terminal 18. Note that the comparison circuit 12
For 0 and 122, malfunctions caused by noise (especially impulsive noise) can be prevented by temporally averaging and comparing the input signals.

The low frequency component at the low frequency output terminal 13 of the low frequency/high frequency separation circuit 19 and the high frequency component whose amplitude has been controlled at the output terminal 17 of the color signal amplitude control circuit 14 are added by the adding circuit 20 to form Y/C.
The signal is input to the separation circuit 2.

The Y/C separation circuit separates the television signal from the addition circuit 20 in which the amplitude of the high frequency component is controlled into a luminance signal and a carrier color signal, outputs the former to the luminance signal output terminal 3, and outputs the latter to the color signal saturation signal. It is output to the input terminal 25 of the degree adjustment circuit 24. The color signal saturation adjustment circuit 24 inputs the carrier color signal from the input terminal 25 by applying it to one input of the multiplication circuit 123 and multiplying it by the saturation designation signal from the saturation adjustment input terminal 16 which is applied through the switch 124. The amplitude of the carrier color signal is adjusted and outputted to the carrier color signal terminal 7.

In addition, when the integration circuit output 119 is fixed, the signal from the color burst presence/absence signal terminal 18 from the integration circuit 117 of the color signal amplitude control circuit 14 is transmitted to the Y/C separation circuit 2.
At the same time, the band restriction to the luminance signal output terminal 3 is canceled, and the switch 124 of the color signal saturation adjustment circuit 24 is turned off to set one input of the multiplication circuit 123 to zero, thereby transmitting the signal to the carrier color signal output terminal 7. Cut off.

As explained above, the configuration shown in FIG. 3 is a digital implementation of the configuration shown in FIG. 1, and operates accurately.

However, when the amplitude of the high frequency component is significantly increased by the color signal amplitude control circuit 14, quantization noise due to AD conversion is also increased in the high frequency component, which may cause disturbances on the screen. The embodiment shown in FIG. 5 is an improvement on the above problem, and can be used even if the number of bits of AD conversion is reduced. In accordance with the above principle, in the configuration shown in FIG. 5, low frequency and high frequency separation and amplitude control of high frequency components are performed before AD conversion.

That is, in FIG. 5, the television 4 of the signal input terminal 1
The signal g is applied to an analog low-high frequency separation circuit 29. The low frequency high frequency separation circuit 29 separates the signal from the input terminal 1 into 1
It is input to delay circuits 201 and 202 which are connected in cascade and have a delay of 40 nS. The low frequency output terminal 213 has coefficient multipliers 203, 204 and 20 connected to the input of the delay circuit 201, respectively.
A signal obtained by adding the signals multiplied by 5 by 5 in the summation circuit 206 is output. The high frequency output terminal 215 has a delay of 20
The coefficients of m- are sent to the outputs of 2 and 207 and 208, respectively.
The signals multiplied by 209 and 209 are added in a summation circuit 210, and a signal is output. The delay times of the delay circuits 201 and 202 are the same as those of the delay circuits 101 and 102 in FIG. 3, and the tap gain as a transversal filter for each signal is also the same as that of the low-frequency high-frequency separation circuit 19 in FIG. Because it will be the same.

Similar to the separation circuit 19, the wave number characteristics of the gain to each output terminal of the low-high frequency separation circuit 29 are as shown in FIG. A circuit such as the low frequency high frequency separation circuit 29 is, for example,
It can be implemented using switched capacitor circuits in MO8 integrated circuits.

The low frequency output terminal 213 of the low frequency high frequency separation circuit 29 is connected to one input of the adding circuit 220, and the high frequency output terminal 215
is connected to the other input of the summing circuit 220 via the variable gain amplifier 214. The variable gain amplifier 214 is an amplifier whose gain can be controlled by the potential of the control input, and may be an AC-coupled amplifier since it handles signals that do not include DC. The television signal, which is the output of the adder circuit 220 and whose amplification of high-frequency components is controlled, is digitized by the AD converter 221 .

The output of the AD converter 221 is first applied to one of the delay circuit 222 and the subtraction circuit 223 in order to detect the amplitude of the color burst and control the amplitude of the high frequency component. The delay circuit 222 is a circuit that provides a two-clock period delay, and its output is provided to the other input of the subtraction circuit 223. The subtraction circuit 223 reduces the amplitude of the carrier color subcarrier by 2.
The DC component is multiplied, the DC component is cut off, the output is output, and the output is input to the square circuit 224. The output of the square circuit 224 is input to a one-clock period delay circuit 225 and added to the output of the delay circuit 225 by an adder circuit 226.

If the output of the AD converter 221 is a carrier color signal, the output of the adder circuit 226 will be four times the square of the amplitude of the carrier color signal (color burst during the burst period). The reason why the output is four times different from the output of the addition circuit 113 in FIG. 3 is that the amplitude of the carrier color signal is doubled by the delay circuit 222 and the subtraction circuit 223. The output of the adder circuit 226 is subtracted by the subtracter circuit 227 from the value four times the square of the normal amplitude of the color burst applied to the burst reference amplitude terminal 228 .

The output of subtraction circuit 227 is given to integration circuit 229. The integrating circuit 229 integrates the output of the subtracting circuit 227 only during the period in which a color burst exists, which is indicated by the signal at the burst sampling signal terminal 118, and when the integrated value reaches a predetermined upper limit, it outputs one pulse to the upper limit pulse terminal 230. At the same time, the upper limit value is subtracted from the integral value, and when the integral value reaches the lower limit value, one pulse is output to the lower limit pulse terminal 231 and the lower limit value is added to the integral value. The pulse at the upper limit pulse terminal 231 turns on the switch 234, which charges the integrating capacitor 232 with the current g233, for the duration of the pulse, and the pulse at the lower limit pulse terminal 231 turns on the switch 234, which discharges said capacitor 232 by the current source 235.
36 is turned on for the duration of the pulse. Integrating capacitor 232
The terminal to be charged and discharged is connected to the control input terminal 237 of the variable gain amplifier 214.

The terminal 237 controls the variable gain amplifier 214 so that the gain increases when the voltage at the terminal 237 is high and decreases when the voltage at the terminal 237 is low. Here, the voltage at the terminal 237 is the output of the subtraction circuit 227, that is, the integrated value of the difference between the square of the amplitude of the regular color burst and the square of the amplitude of the color burst output from the AD converter 221, multiplied by 4. Proportional. Therefore, the amplitude of the color burst output from the AD converter 221 is controlled to be equal to the normal amplitude by negative feedback via the gain of the variable amplifier 214. Thereby, when the signal at the input signal terminal 1 is a color television signal, the amplitude of the carrier color signal output from the AD converter 221 and the amplitude of the high frequency component of the luminance signal are controlled to appropriate values.

Further, regarding the control of the amplitude of the carrier color signal and the amplitude of the high frequency component of the luminance signal, the following additional control is performed.

First, the output of an OR circuit 238 using an upper limit pulse terminal 230 and a lower limit pulse terminal 231 is connected to an integrating circuit 229 via an integrating circuit reset circuit 239.

When the reset circuit 238 detects that no pulse is generated at either the upper limit pulse terminal 230 or the lower limit pulse terminal 231 for a predetermined fixed period or more, the reset circuit 238 sets the integral value of the integrating circuit 229 to a value shorter than the fixed period. The period is set at the center between the upper limit value and the lower limit value. As a result, after the amplitude of the color burst is controlled to a normal value with sufficient accuracy, generation of upper limit pulses and lower limit pulses due to noise etc. is suppressed, and the voltage at the control input terminal 237 of the variable gain amplifier 2] 4 is prevented from fluctuating. This prevents color unevenness on the lunar surface. When the amplitude of the color burst deviates from the normal value, the reset circuit 239 detects the occurrence of an upper or lower limit pulse within the cycle of the integral value setting and cancels the setting operation, thereby adjusting the amplitude of the color burst. Control is resumed.

Next, the control input terminal 237 of the variable gain amplifier 214 is
It is also input to the integrating capacitor control circuit 240. Integrating capacitor control circuit 240 outputs color burst presence/absence signal terminal 18 when a color burst cannot be detected and the voltage at control terminal 237 becomes higher than a predetermined voltage because the signal at input terminal 1 is a black and white television signal. A signal indicating that no color burst is detected is outputted, and a switch 242 connecting the standard gain power supply 241 to the integrating capacitor 232, ie, the control terminal 237, is turned on. Standard gain? The voltage of 1PJ241 is smaller than the predetermined voltage of variable gain amplifier 2.
This is the voltage that makes the gain of 14 approximately 1. By this Jt,
If a color burst cannot be detected, the high frequency component can be applied to the output of the AD converter 221 with the same amplitude as the input signal terminal 1.

Furthermore, the comparator circuit 243 finds a value four times the square of the amplitude of the color burst output from the AD converter 221 based on the signal of the burst sampling terminal 118 from the output of the adder circuit 226, and this value is determined. When the color burst is greater than the specified limit, the signal at the color burst presence/absence signal terminal 18 from the integrating capacitor control circuit 238 is changed to a color burst signal, and the switch 242 is turned off. As a result, when a color burst appears in the signal at the input terminal 1, it is possible to return to amplitude control of high frequency components based on bursts.

The configuration and operation of the amplitude control of the high frequency component in the fifth part 1 have been described above. In FIG. 5, instead of the output of the adder circuit 20 in FIG. 3, the output of the AD converter 221 is input to the circuit 2 in Y/C portions, and the configuration and operation of the subsequent portions are as follows.
Same as Figure 3. The configuration of the fifth r2+ is slightly modified from the basic configuration shown in FIG. 1 in that the amplitude of the color burst is detected after adding the high frequency component and the low frequency component. However, the operation seen from the input to the output is the same as the configuration shown in FIG. 3 except for the influence of the quantization frustum of the AD converter. In the configuration shown in FIG. 5, the AD converter digitizes a signal in which the amplitude of the high frequency component is controlled, and the high frequency range of the quantized shoe sound is not amplified.
The number of pins can be reduced compared to the AD converter shown in the figure.

In addition, in the explanation so far, the input color television signal is
Although the TSC method has been described above, the present invention is based on the TSC method.
The present invention can be applied to the 5ECE system by simply changing the tarock frequency of digital processing, and can also be applied to the 5ECE system in principle.

〔Effect of the invention〕

1: As explained above, according to the present invention, the amplitude of the high frequency component of the composite color television signal, including the high frequency component of the luminance signal, can be controlled and divided into the carrier color signal and the luminance signal.
Image quality on both sides of image reception can be improved. Particularly, the present invention exhibits great effects when other image quality improvement means such as Y/C separation using inter-frame differences and sequential scanning are used in combination.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the basic configuration of an embodiment of the present invention, FIG. 2 is a block diagram showing the configuration of a conventional example, and FIG.
The figure is a block diagram of a circuit that realizes the configuration of Figure 1 through digital processing. Figure 4 is a graph showing an example of the frequency characteristics of the low-high frequency separation circuit used in the present invention. Figure 5 is a graph showing an example of the frequency characteristics of the low-high frequency separation circuit used in the present invention. FIG. 3 is a block diagram of a circuit showing another embodiment using digital processing. K... TV signal input terminal, 2... Y/C shunt shunt circuit... Brightness No. 42 output terminal,... 1... Color signal amplitude, :] control circuit, 7... Transport color signal output terminal, 8
, 18... Color burst presence/absence No. 43 terminal g, 1g
, 2g...Low and high frequency separation circuit, ]-1,221...
A T) converter, 14... color signal amplitude control circuit, 20
．． '-03,104°105 + 1131220!
2.26... Addition circuit, 2.1... Color signal saturation sub-tube circuit, 1011102°112.201,202,2
22, 225...Delay circuit, 106, 203, 204
,205,207゜208.209... Coefficient unit, 10
7,115,223°227...Subtraction circuit, 109,1
11,123...Multiplication circuit, 110,224...Squaring circuit, 116°124.234,236,240...
・Switch, 1.17, 229...Integrator circuit, 118
...Burst extraction signal terminal, 120, 121, 12
2,243... Comparison circuit, 206,210... Summing circuit, 214... Variable gain amplifier, 232... Integrating capacitor, 233.235... Current source, 238...
・OR circuit, 239...integrator circuit reset circuit, 2
40...Integral compilation 4 Figure

Claims (1)

[Claims] 1. Separating a high-frequency component including a carrier color signal from an input composite color television signal, controlling the amplitude of the high-frequency component based on the amplitude of a color burst, and controlling the amplitude of the high-frequency component with reference to the amplitude of a color burst. adding a high frequency component to a signal containing at least a low frequency component of the input composite color television signal separated from the input composite color television signal, and separating a luminance signal and a carrier chrominance signal from the summed signal; Alternatively, the television signal processing circuit is characterized in that a luminance signal is separated from the added signal and a carrier color signal is separated from the amplitude-controlled high frequency component. 2. Adding the amplitude-controlled high-frequency component to a signal separated from the input composite color television signal and including at least the low-frequency component of the composite color television signal, and adding a luminance signal and a carrier color signal from the added signal. or A/D converting the added signal in a television signal processing circuit that separates a luminance signal from the added signal and separates a carrier chrominance signal from the amplitude-controlled high frequency component. 2. The television signal processing circuit according to claim 1, wherein the television signal processing circuit performs digital processing.