JPH06276545A - Y/c separator circuit - Google Patents

Abstract

PURPOSE:To obtain the Y/C separator circuit with simple configuration and high accuracy. CONSTITUTION:A chrominance subcarrier signal synchronously with a color burst signal is multiplied for a vertical synchronizing signal period at a 1st adder 10 and the multiplexed composite signal is separated into a brightness signal and a chroma signal by a 1H delay line 1. Then a carrier component in an output signal from the 1st adder 10 and a residual carrier component included in the brightness signal of a 2nd adder 3 are multiplied by a multiplier 7 for a vertical synchronizing signal period. Then an output signal from the multiplier 7 controls a gain variable amplifier make the separation between the brightness signal and the chroma signal to be an optimum state at all times.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video signal processing device such as a TV receiver, which uses a 1H (horizontal scanning period) delay line for a video signal in which a luminance signal and a chroma signal are combined.
The present invention relates to a Y / C separation circuit that separates a luminance signal and a chroma signal.

[0002]

2. Description of the Related Art Conventionally, a glass delay line or a CCD delay line has been generally used as a 1H delay line, but the insertion loss of these delay lines is not constant but has individual variations.

On the other hand, one of the important performance items in the Y / C separation circuit is the degree of separation of the luminance signal and the chroma signal (depth of comb characteristic).

Therefore, in the conventional circuit, as shown in FIG.
In order to make the chroma component amplitudes of the signal that has passed through the 1H delay line 1 and the signal that does not pass through the 1H delay line 1, a variable gain amplifier 2 in the manufacturing process of a video signal processing device such as a TV receiver
Had to be adjusted. That is, the variation related to the insertion loss of the 1H delay line 1 is corrected to an optimum state by adjusting the variable gain amplifier 2, and the signals passing through the 1H delay line 1 and the signals not input are input to the adder 3 and the subtractor 4, respectively. , The luminance signal and the chroma signal were extracted from each.

However, in the above circuit, it was necessary to adjust the variable gain amplifier 2 in advance.

Therefore, the present applicant has applied for Japanese Patent Application No. 3-141967 as a solution to the drawbacks of the conventional circuit. As shown in FIG. 3, this circuit uses a signal which does not pass through the 1H delay line 1 (or has passed through) so that the circuit performs a stable convergence operation when the color burst signal in the luminance signal output of the Y / C separation circuit is minimized. Signal) and the color burst signal of the luminance signal output are multiplied by the multiplier 7, and the voltage control type variable gain amplifier 5 is controlled by the output signal of the multiplier 7 to make the amplitude adjustment unadjusted.

[0007]

However, the improved conventional circuit automatically corrects the insertion loss amount of the 1H delay line or the like by detecting the amplitude of the color burst signal. Therefore, when a signal having a large burst level and a small noise is input to a signal such as a weak electric field or VTR reproduction, it is difficult to accurately detect the signal amplitude. That is, the Y / C separation characteristic is the level of the input signal and the S /
There is a problem that it is influenced by N and the like.

The present invention has been made in view of the above-mentioned drawbacks, and an object thereof is to obtain a highly accurate Y / C separation circuit with a simple structure.

[0009]

According to the present invention, there is provided a second signal comprising a first signal composed of a color burst signal and a chroma signal and a luminance signal having a frequency interleave relationship with the first signal.
In the Y / C separation circuit that separates the composite signal with the signal of (1) into a chroma signal and a luminance signal by delaying it using a 1H (horizontal scanning period) delay line, a color subcarrier signal synchronized with the color burst signal is generated. Multiplexing means for multiplexing in the vertical synchronizing signal period of the combined signal, variable gain amplifier for adjusting the amplitude of the signal passed through the 1H delay line, output of separated luminance signal and output from the multiplexing means. Y / C, characterized in that it comprises a multiplying means for multiplying by and a low-pass filter for taking out a DC output signal from the multiplying means, and controlling the gain of the variable gain amplifier by the output signal from the low-pass filter. It is a separation circuit.

Further, according to the present invention, a composite signal of a first signal composed of a color burst signal and a chroma signal and a second signal composed of the first signal and a luminance signal related to frequency interleaving is 1H (horizontal scanning). (Period) Y / separated into a chroma signal and a luminance signal by delaying using a delay line
In the C separation circuit, multiplexing means for multiplexing the color subcarrier signal synchronized with the color burst signal in the vertical synchronizing signal period of the composite signal, and a variable gain amplifier for adjusting the amplitude of the signal passed through the 1H delay line And a low-pass filter for extracting a DC output signal from the multiplying means, and a multiplying means for multiplying the output of the separated luminance signal and the output from the 1H delay line, and an output signal from the low-pass filter. The Y / C separation circuit is characterized in that the gain of the variable gain amplifier is controlled by.

[0011]

In the present invention, the color subcarrier signal synchronized with the color burst signal is multiplexed by the adder in the vertical synchronization period, and the multiplexed composite signal is separated into the luminance signal and the chroma signal by the 1H delay line. Then, the color burst signal of the output signal from the first adder (or the signal that has passed through the 1H delay line) and the color burst signal of the luminance signal output from the second adder are multiplied in the vertical synchronization signal period, and the multiplication is performed. The variable gain amplifier is controlled by the output signal of the device to keep the separation degree between the luminance signal and the chroma signal at an optimum state.

[0012]

FIG. 1 shows an embodiment of the present invention, which will be described below.

First, the composite video signal and the color subcarrier synchronized with the color burst signal of the composite video signal created by a reference oscillator or the like are input to the first adder 10. The operation of the first adder 10 is controlled by the vertical sync signal output from the vertical sync separation circuit 9. During the vertical sync period, the composite video signal and the color subcarrier are added and output from the first adder 10. During the period other than the vertical synchronization period, the composite video signal operates so as to be output from the first adder 10 through. That is,
The output signal from the first adder 10 becomes a signal in which the color subcarrier from the reference oscillator is superimposed only during the vertical blanking period of the composite video signal. (Hereinafter, the output signal from the first adder 10 is referred to as a carrier multiplexed signal.) The carrier multiplexed signal includes the second adder 3, one input terminal of the subtractor 4, the first high-pass filter 11, and the subtractor. Input to 4 and 1H
Input to the delay line 1. Here, the carrier multiplexed signal is 1
After being delayed by one horizontal period by the H delay line 1, it is adjusted to a predetermined gain by the voltage control type variable gain amplifier 5 and input to the other input terminals of the second adder 3 and the subtractor 4.
Then, the luminance signal is output from the second adder 3 and the chroma signal is output from the subtractor 4.

By the way, the above-mentioned first high-pass filter 1
The carrier wave multiplex signal input to 1 has a carrier wave component extracted by the first high-pass filter 11 and input to one input terminal of the multiplier 7. On the other hand, the carrier wave component obtained by extracting the output signal of the second adder 3 by the second high-pass filter 12 is input to the other input terminal of the multiplier 7. That is, the residual carrier component contained in the luminance signal of the second adder 3 is extracted and input to the multiplier 7.

Next, the detection signal from the multiplier 7 is input to the voltage control type variable gain amplifier 5 through the low pass filter 8 which operates only in the vertical synchronizing signal period, and the gain control of the voltage control type variable gain amplifier 2 is performed. As a result, the residual carrier component included in the luminance signal output is minimized.

Here, the multiplier 7 is configured to output in the plus direction (in the direction in which the output DC voltage rises) with the in-phase input and in the minus direction (in the direction in which the output DC voltage falls) with the anti-phase input. There is. Further, the voltage-controlled variable gain amplifier 5 is configured such that the gain changes according to the control voltage given from the low-pass filter 8, the gain increases as the control voltage increases, and the gain decreases as the control voltage decreases. ing.

Next, the specific operation of the Y / C separation circuit of the present invention will be described.

First, when the signal levels input to the second adder 3 are equal, since the phase difference of the carrier signals input to the second adder 3 is 180 degrees, the luminance output from the second adder 3 No residual carrier component is detected in the signal. Therefore, the detection output of the multiplier 7 becomes zero, so that the gain of the voltage-controlled variable gain amplifier 5 is not controlled and is in a stable state.

Next, when the output level of the voltage controlled variable gain amplifier 5 is higher than the output level of the first adder 10, the voltage controlled variable gain is included in the luminance signal from the second adder 3. The residual carrier component due to the amplifier 5 appears. Since the phase at that time is in anti-phase with the carrier wave of the output of the first adder 10 (in-phase with the output of the voltage controlled variable gain amplifier 5), the carrier wave signals respectively input to the multipliers 7 are The phase difference also becomes opposite. Therefore, the output from the multiplier 7 becomes a negative output, so that the output from the low-pass filter 8 decreases, and the voltage-controlled variable gain amplifier 5 operates so as to reduce the gain.

Then, the gain of the voltage-controlled variable gain amplifier 7 is controlled so that the carrier levels of the signals finally input to the second adder 3 become equal.

When the output level from the voltage-controlled variable gain amplifier 5 is smaller than the output level from the first adder 10, the luminance signal from the second adder 3 contains the first level.
The residual carrier component due to the adder 3 appears. Then, the phase at that time is in phase with the carrier wave of the output of the first adder 10 (opposite phase with respect to the output of the voltage control type variable gain amplifier 5), so that the carrier wave signals input to the multipliers 7 are The phase difference is also in phase. Therefore, the output from the multiplier 7 becomes a positive output, so that the output from the low-pass filter 8 rises and the voltage-controlled variable gain amplifier 5 operates so as to increase the gain.

Then, the gain of the voltage-controlled variable gain amplifier 7 is controlled so that the carrier levels of the signals finally input to the second adder 3 become equal.

As described above, since the low-pass filter 8 is supplied with the vertical synchronizing signal and thus operates only in the vertical synchronizing period, the voltage-controlled variable gain amplifier 5 can be accurately operated. Can work.

Further, in the present embodiment, the carrier component from the first adder 10 and the residual carrier component contained in the luminance signal from the second adder 3 are multiplied, and the voltage-controlled variable gain is obtained by this multiplication output. Although the amplifier 5 is controlled, the carrier wave component included in the signal that has passed through the 1H delay line 1 is multiplied by the residual carrier wave component included in the luminance signal from the second adder 3, and the voltage output is variable by this multiplication output. The gain amplifier 5 may be controlled.

[0025]

According to the present invention, a composite signal of a first signal composed of a color burst signal and a chroma signal and a second signal composed of the first signal and a luminance signal related to frequency interleaving is 1H (horizontal scanning). (Period) In a Y / C separation circuit that separates a chroma signal and a luminance signal by delaying using a delay line, a color subcarrier signal synchronized with the color burst signal is multiplexed in a vertical synchronization signal period of the composite signal. Multiplexing means, a variable gain amplifier for adjusting the amplitude of the signal passed through the 1H delay line, multiplying means for multiplying the output of the separated luminance signal and the output from the multiplexing means, and the multiplying means And a low-pass filter for extracting the DC output signal of, and controlling the gain of the variable gain amplifier by the output signal from the low-pass filter. More, even for noisy video signals, such as time or during VTR playback weak electric field, without deteriorating the separation of the luminance signal and chroma signal, it can be realized without adjustment of the amplitude direction.

[Brief description of drawings]

FIG. 1 is a block diagram showing a Y / C separation circuit of the present invention.

FIG. 2 is a block diagram showing a Y / C separation circuit of a conventional circuit.

FIG. 3 is a block diagram showing a Y / C separation circuit of a conventional circuit.

[Explanation of symbols]

 1 1H Delay Line 2 Gain Variable Amplifier 3 First Adder 4 Subtractor 5 Voltage Controlled Variable Gain Amplifier 6 Burst Amplifier 7 Multiplier 8 Low Pass Filter 9 Vertical Sync Separation Circuit 10 First Adder 11 First High Pass Filter 12 Second high-pass filter

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[Procedure amendment]

[Submission date] June 11, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Claim 1

[Correction method] Change

[Correction content]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] Claim 2

[Correction method] Change

[Correction content]

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Change

[Correction content]

[0009]

According to the present invention, there is provided a second signal comprising a first signal composed of a color burst signal and a chroma signal and a luminance signal having a frequency interleave relationship with the first signal.
In the Y / C separation circuit that separates the composite signal with the signal of (1) into a chroma signal and a luminance signal by delaying it using a 1H (horizontal scanning period) delay line, a color subcarrier signal synchronized with the color burst signal is generated. Multiplexing means for multiplexing in the vertical retrace period of the composite signal, a variable gain amplifier for adjusting the amplitude of the signal passed through the 1H delay line, an output of the separated luminance signal and an output from the multiplexing means. Y / C, characterized in that it comprises a multiplying means for multiplying by and a low-pass filter for taking out a DC output signal from the multiplying means, and controlling the gain of the variable gain amplifier by the output signal from the low-pass filter. It is a separation circuit.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0010

[Correction method] Change

[Correction content]

Further, according to the present invention, a composite signal of a first signal composed of a color burst signal and a chroma signal and a second signal composed of the first signal and a luminance signal related to frequency interleaving is 1H (horizontal scanning). (Period) Y / separated into a chroma signal and a luminance signal by delaying using a delay line
In the C separation circuit, multiplexing means for multiplexing the color subcarrier signal synchronized with the color burst signal in the vertical blanking period of the composite signal, and a variable gain amplifier for adjusting the amplitude of the signal passed through the 1H delay line And a low-pass filter for extracting a DC output signal from the multiplying means, and a multiplying means for multiplying the output of the separated luminance signal and the output from the 1H delay line, and an output signal from the low-pass filter. The Y / C separation circuit is characterized in that the gain of the variable gain amplifier is controlled by.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0011

[Correction method] Change

[Correction content]

[0011]

According to the present invention, the color subcarrier signal synchronized with the color burst signal is multiplexed by the adder during the vertical blanking period, and the multiplexed composite signal is separated into the luminance signal and the chroma signal by the 1H delay line. Then, the color burst signal of the output signal from the first adder (or the signal that has passed through the 1H delay line) and the color burst signal of the luminance signal output from the second adder are multiplied in the vertical blanking period, and the multiplication is performed. The variable gain amplifier is controlled by the output signal of the device to keep the separation degree between the luminance signal and the chroma signal at an optimum state.

[Procedure correction 6]

[Document name to be amended] Statement

[Correction target item name] 0013

[Correction method] Change

[Correction content]

First, the composite video signal and the color subcarrier synchronized with the color burst signal of the composite video signal created by a reference oscillator or the like are input to the first adder 10. The operation of the first adder 10 is controlled by the vertical sync signal output from the vertical sync separation circuit 9. During the vertical blanking period, the composite video signal and the color subcarrier are added and output from the first adder 10. , Except for the vertical blanking period, the composite video signal operates so as to be output from the first adder 10 through. That is,
The output signal from the first adder 10 becomes a signal in which the color subcarrier from the reference oscillator is superimposed only during the vertical blanking period of the composite video signal. (Hereinafter, the output signal from the first adder 10 is referred to as a carrier multiplexed signal.) The carrier multiplexed signal includes the second adder 3, one input terminal of the subtractor 4, the first high-pass filter 11, and the subtractor. Input to 4 and 1H
Input to the delay line 1. Here, the carrier multiplexed signal is 1
After being delayed by one horizontal period by the H delay line 1, it is adjusted to a predetermined gain by the voltage control type variable gain amplifier 5 and input to the other input terminals of the second adder 3 and the subtractor 4.
Then, the luminance signal is output from the second adder 3 and the chroma signal is output from the subtractor 4.

[Procedure Amendment 7]

[Document name to be amended] Statement

[Name of item to be corrected] 0015

[Correction method] Change

[Correction content]

Next, the detection signal from the multiplier 7 is input to the voltage control type variable gain amplifier 5 via the low pass filter 8 which operates only in the vertical retrace period, and the gain control of the voltage control type variable gain amplifier 2 is performed. As a result, the residual carrier component included in the luminance signal output is minimized.

Claims (2)

[Claims] 1. A 1H composite signal of a first signal composed of a color burst signal and a chroma signal and a second signal composed of a luminance signal having a frequency interleave relationship with the first signal.
(Horizontal scanning period) In a Y / C separation circuit for separating a chroma signal and a luminance signal by delaying using a delay line, a chrominance subcarrier signal synchronized with the color burst signal is vertically synchronized with the synthesized signal. A gain variable amplifier for adjusting the amplitude of the signal that has passed through the 1H delay line, multiplication means for multiplying the output of the separated luminance signal and the output from the multiplexing means, A Y / C separation circuit comprising: a low-pass filter for extracting a DC output signal from the multiplication means, and controlling the gain of the variable gain amplifier by the output signal from the low-pass filter. 2. A 1H composite signal of a first signal composed of a color burst signal and a chroma signal and a second signal composed of a luminance signal having a frequency interleave relationship with the first signal.
(Horizontal scanning period) In a Y / C separation circuit for separating a chroma signal and a luminance signal by delaying using a delay line, a chrominance subcarrier signal synchronized with the color burst signal is vertically synchronized with the synthesized signal. Multiplex means for multiplexing, a variable gain amplifier for adjusting the amplitude of the signal passed through the 1H delay line, multiplication means for multiplying the output of the separated luminance signal by the output from the 1H delay line, A Y / C separation circuit comprising: a low-pass filter for extracting a DC output signal from the multiplication means, and controlling the gain of the variable gain amplifier by the output signal from the low-pass filter.