JP3503442B2 - 2-line YC separator - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention can reduce the cost by reducing the number of delay circuits for delaying the horizontal period, and can greatly reduce the comb filter operation error as compared with the conventional one. It relates to a comb filter.

[0002]

2. Description of the Related Art In recent years, a two-line YC separation device has been regarded as important as a device for YC separation at low cost and with high accuracy.

FIG. 11 is a block diagram of a two-line YC separation device disclosed in Japanese Patent Application No. 62-272952 (Japanese Patent Laid-Open No. 1-1174494). Figure 1
1, reference numeral 2201 is a video composite signal signal, 2202
Is one horizontal period delay circuit, 2203 is a subtraction circuit, 220
4 is a subtraction circuit, 2205 is a bandpass filter circuit, 2206 is a switch circuit, 2207 is a color subcarrier frequency trap circuit, 2208 is a switch circuit, and 2209.
Is a luminance signal output, 2210 is a chroma signal output, 2211
Is a low pass filter circuit, 2212 is a YL correlation detection circuit, 2213 is a band pass filter circuit, 2214 is a chroma detection circuit, and 2215 is an AND circuit.

The operation of the 2-line YC separation circuit configured as described above will be described below. First,
The current video composite signal 2201 to one horizontal period delay circuit 220
For the signal obtained by subtracting the signal after passing 2, the YL correlation output signal obtained through the low-pass filter circuit 2211 and the band-pass filter circuit 2213 are detected by extracting the signal at the center of the color subcarrier frequency. Create an output signal and control the comb filter with both AND outputs. That is, only when the YL correlation output circuit 2212 determines that there is no correlation and the chroma detection circuit 2214 determines that there is a chroma signal, the switch circuit 2208 is turned on and at the same time the switch circuit 2206 is applied to the current video composite signal 2201 side. Otherwise, for example, when the YL correlation detection circuit 2212 determines that there is a correlation, or when the YL correlation output circuit 2212
If the chroma detection circuit 2214 determines that there is no chroma signal, the switch circuit 2208
Is turned off, and the switch circuit 2206 is pushed to the bandpass filter circuit 2205 side.

[0005]

However, with the above configuration, the YC separation cannot be performed accurately with respect to the input signal having the pattern as shown in FIG. FIG. 12A is a pattern in which the vertical stripes of the luminance signal whose frequency is the frequency of the color subcarrier in the vertical direction of the screen are up to the 3Hth point, and the luminance signal disappears from the 4th hour.

Here, FIG. 12A shows a video composite signal, FIG. 12B shows an output signal of the one horizontal period delay circuit 2202, and FIG. 12C shows an output signal of the subtraction circuit 2203. , FIG. 12D shows the low-pass filter circuit 2
12 (e) is the output result of the YL correlation detection circuit 2212, FIG. 12 (f) is the output result of the chroma detection circuit 2214, and FIG. 12 (g) is the chroma signal. 12 (h) shows the luminance signal. Here, since the output signal of the bandpass filter circuit 2205 passes through the frequency component of the color subcarrier of the output signal of the subtraction circuit 2203, when the pattern as shown in FIG. The output signal and the output signal of the bandpass filter circuit 2205 are the same signal. FIG. 12E shows 0, Y when there is YL correlation.
It is shown as 1 when there is no L correlation, and FIG. 12 (f) shows 1 when there is a chroma signal and 0 when there is no chroma signal.
Is shown. Further, FIG. 12 (i) is a luminance signal that should be originally output, and FIG. 12 (j) is a chroma signal that is originally desired to be output.

Here, paying attention to FIGS. 12 (e) and 12 (f), the YL correlation detection circuit 2212 judges that there is no correlation for each line of 1H, 2H, 3H, 4H, 5H,
Moreover, since the chroma detection circuit 2214 does not judge that there is a chroma signal, the switch circuit 2208 is off and the switch circuit 2206 is the bandpass filter circuit 2205.
Push it to the side. In this way, the luminance signal output is the bandpass filter circuit 2 from the current image composite signal FIG.
The output signal of 205, that is, the output signal of the subtraction circuit 2203 is the result of subtraction of FIG. 12C, and the signal of FIG. 12H is output. The chroma signal output is the output signal of the bandpass filter circuit 2205, that is, the output signal of the subtraction circuit 2203, as shown in FIG. 12C, and FIG.
Signal is output.

That is, in the pattern in which the vertical stripes of the luminance signal whose frequency is the frequency of the color subcarrier in the vertical direction of the screen as shown in FIG. The luminance signal is shown in FIG. 12 (h), and the chroma signal is shown in FIG. 12 (g). On the other hand, the signal originally desired to be output is the luminance signal shown in FIG.
(I), the chroma signal is shown in FIG.

As described above, according to the conventional technique, the YC separation is not performed properly, and the horizontal resolution is deteriorated, or the originally colorless portion is colored, or the luminance component appears in the originally colored portion. It had the problem of occurring.

[0010]

In order to solve the above problems, a 2-line YC separation apparatus of the present invention is provided with a first delay circuit for delaying an input composite video signal by an integral multiple of a horizontal period. Of the first bandpass filter circuit, the second bandpass filter circuit receiving the output signal of the first delay circuit as an input, and the first and second bandpass filter circuits A Y correlation detection circuit that receives an output signal, a C level detection circuit that receives the output signals of the first and second bandpass filter circuits, and a C level that receives the output signal of the C level detection circuit.
A correlation detection circuit, a second delay circuit that delays the output signal of the Y correlation detection circuit for a horizontal period, a third delay circuit that delays an output signal of the C correlation detection circuit for a horizontal period, and the first band. A first inverting circuit that receives the output signal of the pass filter circuit; an arithmetic circuit that receives the output signals of the first and second band pass filter circuits; and a Y correlation detection circuit and a C correlation detection circuit. A first switch determination circuit that receives the output signal and the output signals of the second and third delay circuits as input, the output signals of the Y correlation detection circuit and the C correlation detection circuit, and the second and third delay circuits. Switch deciding circuit receiving the output signal of the second input circuit, a second inverting circuit receiving the output signal of the second bandpass filter circuit, the output signal of the arithmetic circuit and the second inverting circuit. The output signal of the Of the output signal of the band-pass filter circuit of the first switch circuit, the output signal of the first switch determination circuit, the output signal of the arithmetic circuit and the output signal of the second band-pass filter circuit A second switch circuit that switches according to the output signal of the second switch determination circuit; and a three-line comb operation circuit that receives the output signals of the first inverting circuit and the output signals of the first and second switch circuits as inputs. In addition to the configuration of a subtraction circuit that receives the output signal of the first delay circuit and the output signal of the 3-line comb arithmetic circuit and a filter circuit that receives the output signal of the 3-line comb arithmetic circuit, A DC detection circuit that receives the composite video signal thus generated and the output signal of the first delay circuit as an input, detects the difference between the two signals, and detects the level of the DC component; A DC level amplitude detection circuit that removes the frequency component of the color subcarrier from the output signal of the C detection circuit and a multi-burst that determines whether there is correlation or not according to the output signal of the DC level amplitude detection circuit A detection circuit and a DC adaptation circuit that determines whether there is a correlation or not according to the output signal of the DC detection circuit;
A DC correlation detection circuit for determining whether there is correlation or not according to the output signal of the C level amplitude detection circuit, and an AND circuit for taking a logical product of the output signal of the DC correlation detection circuit and the output signal of the Y correlation detection circuit are provided. It is a thing.

In view of the above-mentioned problems, the present invention provides a 2-line YC separation device which has few malfunctions as in the conventional example and has a small horizontal period delay circuit.

[0012]

A two-line YC separation device according to a first aspect of the present invention includes a first delay circuit for delaying an input composite video signal by an integral multiple of a horizontal period, and an input video signal. A first bandpass filter circuit as input,
A second bandpass filter circuit that receives the output signal of the first delay circuit; a Y correlation detection circuit that receives the output signals of the first and second bandpass filter circuits; A C level detection circuit having an output signal of the second band pass filter circuit as an input, a C correlation detection circuit having an output signal of the C level detection circuit as an input, and an output signal of the Y correlation detection circuit having a horizontal period delay A second delay circuit, a third delay circuit that delays the output signal of the C correlation detection circuit for a horizontal period, and a first inverting circuit that receives the output signal of the first bandpass filter circuit as an input. An arithmetic circuit that receives the output signals of the first and second band pass filter circuits as inputs; the Y correlation detection circuit;
A first switch determination circuit that receives the output signal of the correlation detection circuit and the output signals of the second and third delay circuits, the output signals of the Y correlation detection circuit and the C correlation detection circuit, and the second and the second A second switch determination circuit that receives the output signal of the third delay circuit, a second inverting circuit that receives the output signal of the second bandpass filter circuit, an output signal of the arithmetic circuit, and the second The output signal of the second inverting circuit and the output signal of the second bandpass filter circuit
Switching according to the output signal of the switch determination circuit of the first
Switch circuit, the output signal of the arithmetic circuit and the second
Second switch circuit for switching the output signal of the band-pass filter circuit of the present invention by the output signal of the second switch determination circuit, the output signal of the first inverting circuit, and the outputs of the first and second switch circuits A 3-line comb arithmetic circuit that receives a signal; a subtraction circuit that receives the output signal of the first delay circuit and an output signal of the 3-line comb arithmetic circuit; and an output signal of the 3-line comb arithmetic circuit. In addition to the configuration of the input filter circuit, a DC detection circuit that receives the input composite video signal and the output signal of the first delay circuit, detects the difference between the two signals, and detects the level of the DC component, A DC level amplitude detection circuit that removes the frequency component of the color subcarrier from the output signal of the detection circuit and detects the amplitude of the color subcarrier is correlated with the output signal of the DC level amplitude detection circuit. , A multi-burst detection circuit determines No, there correlation in accordance with the output signal of the DC detection circuit,
There is a correlation between the DC adaptation circuit that determines the absence and the output signal of the DC level amplitude detection circuit, and the DC correlation detection circuit that determines the absence, the output signal of the DC correlation detection circuit, and the output signal of the Y correlation detection circuit. An AND circuit that takes a logical product is provided, and it is determined whether the output signal of the DC level amplitude detection circuit is added to the C correlation detection circuit according to the output of the DC adaptation circuit. AND is performed by detecting and using the output signal of the C correlation detection circuit as the color correlation selection signal of the switch determination circuit, and the brightness of the output signal of the Y correlation detection circuit and the DC correlation detection circuit.
The output signal of the circuit is used as a selection signal of the luminance correlation of the switch determination circuit, and YC separation is performed with higher accuracy.

According to another aspect of the present invention, in a two-line YC separation device, a first delay circuit delays an input composite video signal by an integral multiple of a horizontal period, and a first delay circuit receives the input video signal. Band-pass filter circuit, second band-pass filter circuit that receives the output signal of the first delay circuit, and Y correlation detection circuit that receives the output signals of the first and second band-pass filter circuits A C level detection circuit that receives the output signals of the first and second bandpass filter circuits, a C correlation detection circuit that receives the output signal of the C level detection circuit, and a Y correlation detection circuit. A second delay circuit for delaying the output signal in the horizontal period, a third delay circuit for delaying the output signal of the C correlation detection circuit in the horizontal period, and an output signal of the first bandpass filter circuit are input. A first inverting circuit, an arithmetic circuit that receives the output signals of the first and second band pass filter circuits as input, output signals of the Y correlation detection circuit and C correlation detection circuit, and the second and third First switch determination circuit that receives the output signal of the delay circuit of No. 2 and input signals of the output signals of the Y correlation detection circuit and the C correlation detection circuit and the output signals of the second and third delay circuits Switch deciding circuit, a second inverting circuit that receives the output signal of the second bandpass filter circuit, an output signal of the arithmetic circuit, an output signal of the second inverting circuit, and the second band. The first switch circuit that switches the output signal of the pass filter circuit according to the output signal of the first switch determination circuit, the output signal of the arithmetic circuit, and the output signal of the second band pass filter circuit are the second A second switch circuit that switches according to the output signal of the switch determination circuit; a three-line comb arithmetic circuit that receives the output signal of the first inverting circuit and the output signals of the first and second switch circuits as inputs; A subtraction circuit having as inputs the output signal of the delay circuit of No. 1 and the output signal of the three-line comb arithmetic circuit;
In addition to the configuration of the filter circuit that receives the output signal of the 3-line comb arithmetic circuit, the input composite video signal and the output signal of the first delay circuit are input, and the difference between the two signals is calculated to obtain the DC component. A DC detection circuit for detecting the level, and a DC level amplitude detection circuit for removing the frequency component of the color subcarrier from the output signal of the DC detection circuit to detect the amplitude thereof are provided. It is characterized by including a DC correlation detection circuit for determining whether there is correlation or not according to the output signal of the level amplitude detection circuit, and using the output of the DC correlation detection circuit as a selection signal of the luminance correlation of the switch determination circuit. Yes, YC separation is performed with higher accuracy.

According to another aspect of the present invention, in a two-line YC separation device, a first delay circuit that delays an input composite video signal by an integral multiple of a horizontal period, and a first delay circuit that receives the input video signal as input. Band-pass filter circuit, second band-pass filter circuit that receives the output signal of the first delay circuit, and Y correlation detection circuit that receives the output signals of the first and second band-pass filter circuits A C level detection circuit that receives the output signals of the first and second bandpass filter circuits, a C correlation detection circuit that receives the output signal of the C level detection circuit, and a Y correlation detection circuit. A second delay circuit for delaying the output signal in the horizontal period, a third delay circuit for delaying the output signal of the C correlation detection circuit in the horizontal period, and an output signal of the first bandpass filter circuit are input. A first inverting circuit, an arithmetic circuit that receives the output signals of the first and second band pass filter circuits as input, output signals of the Y correlation detection circuit and C correlation detection circuit, and the second and third First switch determination circuit that receives the output signal of the delay circuit of No. 2 and input signals of the output signals of the Y correlation detection circuit and the C correlation detection circuit and the output signals of the second and third delay circuits Switch deciding circuit, a second inverting circuit that receives the output signal of the second bandpass filter circuit, an output signal of the arithmetic circuit, an output signal of the second inverting circuit, and the second band. The first switch circuit that switches the output signal of the pass filter circuit according to the output signal of the first switch determination circuit, the output signal of the arithmetic circuit, and the output signal of the second band pass filter circuit are the second A second switch circuit that switches according to the output signal of the switch determination circuit; a three-line comb arithmetic circuit that receives the output signal of the first inverting circuit and the output signals of the first and second switch circuits as inputs; A subtraction circuit having as inputs the output signal of the delay circuit of No. 1 and the output signal of the three-line comb arithmetic circuit;
In addition to the configuration of the filter circuit that receives the output signal of the 3-line comb arithmetic circuit, the input composite video signal and the output signal of the first delay circuit are input, and the difference between the two signals is calculated to obtain the DC component. Depending on the output signal of the DC detection circuit for detecting the level, the DC level amplitude detection circuit for removing the frequency component of the color subcarrier from the output signal of the DC detection circuit, and the amplitude thereof, and the output signal of the DC level amplitude detection circuit. A multi-burst detection circuit for determining whether there is correlation is provided, and the output of the multi-burst detection circuit is added to the C correlation detection circuit to determine C correlation. It is characterized in that it is used as a selection signal, and YC separation is performed with higher accuracy.

According to another aspect of the present invention, in a two-line YC separation device, a first delay circuit that delays an input composite video signal by an integral multiple of a horizontal period, and a first delay circuit that receives the input video signal as input. Band-pass filter circuit, second band-pass filter circuit that receives the output signal of the first delay circuit, and Y correlation detection circuit that receives the output signals of the first and second band-pass filter circuits A C level detection circuit that receives the output signals of the first and second bandpass filter circuits, a C correlation detection circuit that receives the output signal of the C level detection circuit, and a Y correlation detection circuit. A second delay circuit for delaying the output signal in the horizontal period, a third delay circuit for delaying the output signal of the C correlation detection circuit in the horizontal period, and an output signal of the first bandpass filter circuit are input. A first inverting circuit, an arithmetic circuit that receives the output signals of the first and second band pass filter circuits as input, output signals of the Y correlation detection circuit and C correlation detection circuit, and the second and third First switch determination circuit that receives the output signal of the delay circuit of No. 2 and input signals of the output signals of the Y correlation detection circuit and the C correlation detection circuit and the output signals of the second and third delay circuits Switch deciding circuit, a second inverting circuit that receives the output signal of the second bandpass filter circuit, an output signal of the arithmetic circuit, an output signal of the second inverting circuit, and the second band. The first switch circuit that switches the output signal of the pass filter circuit according to the output signal of the first switch determination circuit, the output signal of the arithmetic circuit, and the output signal of the second band pass filter circuit are the second A second switch circuit that switches according to the output signal of the switch determination circuit; a three-line comb arithmetic circuit that receives the output signal of the first inverting circuit and the output signals of the first and second switch circuits as inputs; A subtraction circuit having as inputs the output signal of the delay circuit of No. 1 and the output signal of the three-line comb arithmetic circuit;
In addition to the configuration of the filter circuit that receives the output signal of the 3-line comb arithmetic circuit, the input composite video signal and the output signal of the first delay circuit are input, and the difference between the two signals is calculated to obtain the DC component. Depending on the output signal of the DC detection circuit for detecting the level, the DC level amplitude detection circuit for removing the frequency component of the color subcarrier from the output signal of the DC detection circuit, and the amplitude thereof, and the output signal of the DC level amplitude detection circuit. A multi-burst detection circuit for determining whether there is correlation or not, and D
A DC adaptive circuit that determines whether there is correlation or not according to the output signal of the C detection circuit, and determines whether to add the output signal of the DC level amplitude detection circuit to the C correlation detection circuit according to the output of the DC adaptation circuit. It is characterized in that the C correlation is detected, the C correlation is detected by the C correlation detection circuit, and the output of the C correlation detection circuit is used as a color correlation selection signal of the switch determination circuit. It is a thing.

According to another aspect of the present invention, in a two-line YC separation device, a first delay circuit that delays an input composite video signal by an integral multiple of a horizontal period, and a first delay circuit that receives the input video signal as input. Band-pass filter circuit, second band-pass filter circuit that receives the output signal of the first delay circuit, and Y correlation detection circuit that receives the output signals of the first and second band-pass filter circuits A C level detection circuit that receives the output signals of the first and second bandpass filter circuits, a C correlation detection circuit that receives the output signal of the C level detection circuit, and a Y correlation detection circuit. A second delay circuit for delaying the output signal in the horizontal period, a third delay circuit for delaying the output signal of the C correlation detection circuit in the horizontal period, and an output signal of the first bandpass filter circuit are input. A first inverting circuit, an arithmetic circuit that receives the output signals of the first and second band pass filter circuits as input, output signals of the Y correlation detection circuit and C correlation detection circuit, and the second and third First switch determination circuit that receives the output signal of the delay circuit of No. 2 and input signals of the output signals of the Y correlation detection circuit and the C correlation detection circuit and the output signals of the second and third delay circuits Switch deciding circuit, a second inverting circuit that receives the output signal of the second bandpass filter circuit, an output signal of the arithmetic circuit, an output signal of the second inverting circuit, and the second band. The first switch circuit that switches the output signal of the pass filter circuit according to the output signal of the first switch determination circuit, the output signal of the arithmetic circuit, and the output signal of the second band pass filter circuit are the second A second switch circuit that switches according to the output signal of the switch determination circuit; a three-line comb arithmetic circuit that receives the output signal of the first inverting circuit and the output signals of the first and second switch circuits as inputs; A subtraction circuit having as inputs the output signal of the delay circuit of No. 1 and the output signal of the three-line comb arithmetic circuit;
In addition to the configuration of the filter circuit that receives the output signal of the 3-line comb arithmetic circuit, the input composite video signal and the output signal of the first delay circuit are input, and the difference between the two signals is calculated to obtain the DC component. Depending on the output signal of the DC detection circuit for detecting the level, the DC level amplitude detection circuit for removing the frequency component of the color subcarrier from the output signal of the DC detection circuit, and the amplitude thereof, and the output signal of the DC level amplitude detection circuit. A DC correlation detection circuit that determines whether there is correlation and an AND circuit that takes a logical product of the output signal of the DC correlation detection circuit and the output signal of the Y correlation detection circuit are provided, and the output of the AND circuit is provided to the switch determination circuit. It is characterized in that it is used as a selection signal for luminance correlation, and more accurately performs YC separation.

According to another aspect of the present invention, in a two-line YC separation device, a first delay circuit that delays an input composite video signal by an integral multiple of a horizontal period, and a first delay circuit that receives the input video signal as input. Band-pass filter circuit, second band-pass filter circuit that receives the output signal of the first delay circuit, and Y correlation detection circuit that receives the output signals of the first and second band-pass filter circuits A C level detection circuit that receives the output signals of the first and second bandpass filter circuits, a C correlation detection circuit that receives the output signal of the C level detection circuit, and a Y correlation detection circuit. A second delay circuit for delaying the output signal in the horizontal period, a third delay circuit for delaying the output signal of the C correlation detection circuit in the horizontal period, and an output signal of the first bandpass filter circuit are input. A first inverting circuit, an arithmetic circuit that receives the output signals of the first and second band pass filter circuits as input, output signals of the Y correlation detection circuit and C correlation detection circuit, and the second and third First switch determination circuit that receives the output signal of the delay circuit of No. 2 and input signals of the output signals of the Y correlation detection circuit and the C correlation detection circuit and the output signals of the second and third delay circuits Switch deciding circuit, a second inverting circuit that receives the output signal of the second bandpass filter circuit, an output signal of the arithmetic circuit, an output signal of the second inverting circuit, and the second band. The first switch circuit that switches the output signal of the pass filter circuit according to the output signal of the first switch determination circuit, the output signal of the arithmetic circuit, and the output signal of the second band pass filter circuit are the second A second switch circuit that switches according to the output signal of the switch determination circuit; a three-line comb arithmetic circuit that receives the output signal of the first inverting circuit and the output signals of the first and second switch circuits as inputs; A subtraction circuit having as inputs the output signal of the delay circuit of No. 1 and the output signal of the three-line comb arithmetic circuit;
In addition to the configuration of the filter circuit that receives the output signal of the 3-line comb arithmetic circuit, the output signal of the Y correlation detection circuit is delayed for a certain time, and the signal within that time is extended to a non-correlation state in time. When the output of the Y correlation detection circuit is provided with a circuit, the result of the correlation detection is used as a selection signal of the switch determination circuit in a state of no correlation, which is more accurate. YC separation is performed.

(Embodiment 1) An embodiment of the invention described in claim 1 of the present invention will be described below with reference to FIG.

In FIG. 1, 101 is a composite video signal 10
A delay circuit that delays 0 by 1 horizontal period, 102 is a bandpass filter circuit that receives the composite video signal 100 as input, 1
Reference numeral 03 is a bandpass filter circuit that receives the output signal of the delay circuit 101, 104 is a C level detection circuit that detects the level of the color signal, and 105 is C correlation detection that receives the output signals of the bandpass filter circuits 102 and 103. A circuit, 106 is a delay circuit that delays the input signal by one horizontal period, 107 and 108 are inverting circuits that invert the input signal,
109 is an arithmetic circuit that outputs the average value of the input signal;
0 and 111 are switch decision circuits that generate switching control signals for the switch circuits 112 and 113, 112 and 113 are switch circuits that switch the flow of signals, and 114 is an output signal from the switch circuits 112 and 113 and the inverting circuit 107, A 3-line comb operation circuit for performing an operation, 115 is a subtraction circuit for subtracting an input signal to output a luminance signal output 117, and 116 is an output signal of the 3-line comb operation circuit 114 for filtering and outputs a color signal 118. A filter circuit 119 for controlling the composite video signal 100
And the output signal of the delay circuit 101 are input to detect the level of the DC component by taking the difference between the two signals, and 120 removes the frequency component of the color subcarrier from the output signal of the DC detection circuit 119. , D to detect its amplitude
A C level amplitude detection circuit, 121 is a DC correlation detection circuit for determining whether there is correlation or not according to the output signal of the DC level amplitude detection circuit 120, and 122 is for determining whether there is correlation or not according to the output signal of the DC detection circuit. DC adaptation circuit, 123
124 is a multi-burst detection circuit that is turned on when the output result of the DC adaptation circuit 122 has a correlation, passes the output signal of the DC level amplitude detection circuit, and turns off when there is no correlation,
Is a Y correlation detection circuit that receives the output signals of the bandpass filter circuits 102 and 103, and 125 is an AND circuit that takes the logical product of the input signals.

The operation of the 2-line YC separation device constructed as described above will be briefly described. The bandpass filter circuits 102 and 103 are filters that pass a band centered on the color subcarrier frequency, and the C level detection circuit 104 detects the level of the color signal from the output signals of the bandpass filters 102 and 103. The C correlation detection circuit 105 uses the result of detecting the level of the color signal in the C level detection circuit 104 and the output result of the multi-burst detection circuit to determine that there is a correlation when the color signal is input, and to determine the correlation otherwise. Judge as none.

As for the DC component, the DC level detection circuit 119 subtracts the output signal of the composite video signal 100 and the delay circuit 101, and the DC level amplitude detection circuit detects the level of the DC component. The DC adaptation circuit 122 receives the output signal of the DC level detection circuit as an input and detects the correlation before passing through the 2-input band pass filter. When the DC adaptation circuit determines that there is a correlation, the multi-burst detection circuit is turned on, and the output signal of the DC level amplitude detection circuit is added to the C correlation detection circuit to control so that the color correlation is enhanced.

On the other hand, the Y correlation detection circuit 124 is a circuit for detecting a luminance signal from the output signals of the band-pass filters 102 and 103, and judges that there is a correlation when the luminance signal is input, and judges that there is no correlation otherwise. To do. From the result of the DC level amplitude detection circuit 120, the DC correlation detection circuit 121 determines that there is correlation when a DC component is input, and determines that there is no correlation otherwise. This DC correlation detection circuit 1
The AND circuit 125 obtains the logical product of the output signal of the reference numeral 21 and the output signal of the Y correlation detection circuit 124 to determine the luminance correlation.

The switch decision circuits 110 and 111 receive the output signal of the C correlation detection circuit 105, the output signal of the AND circuit 125 and the output signal of the delay circuit 106 which receives the output signals of the C correlation detection circuit 105 and the AND circuit 125, respectively. As a result, a switching control signal is generated by the logic shown in FIG. 2 to switch the output signals of the switch circuits 112 and 113. In FIG. 2, (a) shows a logic table of the output signal 143 of the switch circuit 112, and (b) shows the switch circuit 1
13 shows a logic table of 13 output signals 144. Thirteen
0 is the output signal of the DC correlation detection circuit 121, 131 is 13
0 signal delayed by one horizontal period by the delay circuit 106, 13
Reference numeral 2 is a signal obtained by delaying 133 by the delay circuit 106 for one horizontal period, and 133 is an output signal of the C correlation detection circuit 105.
1 if there is a correlation, 130 if there is no correlation, 1
The output signals 143 and 144 of the switch circuits 112 and 113 are converted into the output signal 140 of the inverting circuit 108 and the bandpass filter 10 by the combination of the signals of 31, 32 and 133.
The output signal 141 of No. 3 and the signal of the arithmetic circuit 109 are switched.

The 3-line comb arithmetic circuit 114 is the circuit shown in FIG. 3, which is a filter originally developed for the 3-line comb arithmetic circuit. Here, the input signal is the switch circuit 112, the output signal 143, and the switch circuit 113. Output signal 144 and the output signal 145 of the inverting circuit 107 are input.

The subtraction circuit 115 subtracts the output signal of the delay circuit 101 and the output signal of the 3-line comb operation circuit 114, and outputs a luminance signal output 117. Also, 3
The output signal of the line comb calculation circuit 114 is filtered by the filter circuit 116, and the result is color signal output 11
Output as 8.

FIG. 4 shows the waveform of each part. Color carrier frequencies are extracted from the current signal of (a) and the signal of (b) obtained by delaying the signal of (a) by one horizontal period to obtain (c) and (d). Paying attention to the DC components of (a) and (b), 1 is output when there is a correlation in the DC correlation detection circuit, and 0 is output when there is no correlation. The output of this DC correlation detection circuit is obtained as shown in (e). Similarly, paying attention to (a) and (b), 1 is output when there is a correlation in the DC adaptive circuit, and 0 is output when there is no correlation. The output of this DC adaptation circuit is obtained as shown in (f). Next, paying attention to (c) and (d), 1 is output when the Y correlation detection circuit has a correlation, and 0 is output when there is no correlation.
Is output. The output of this Y correlation detection circuit is obtained as shown in (g). Paying attention to (c) and (d), when the output of the multi-burst detection circuit is 1, the result of the DC level amplitude detection circuit is taken into consideration and 1 is output when there is a correlation in the C correlation detection circuit. If there is no, 0 is output. The output of this C correlation detection circuit is obtained as shown in (h). Further, the output (g) of the Y correlation detection circuit and the output (e) of the DC correlation detection circuit
(I) is the AND of A signal obtained by delaying the signal of (h) by one horizontal period is (j), and a signal obtained by delaying the signal of (i) by one horizontal period is (k). The signals (h), (i), (j), and (k) are input to the switch determination circuits 110 and 111, and the output signals (l) and the output signals (l) of the switch circuits 112 and 113 according to the logic table of FIG.
(M) is obtained. Further, () n is created by inverting the signal of (d), and (l), (m), and (n) are input to 2H before, 1H before, and 0H of the 3-line comb arithmetic circuit of FIG. 3, and output. Get the signal (o). The luminance signal output (p) is obtained by subtracting this output signal from (b). This (o),
The waveform of (p) is the desired signal to be obtained (i) of FIG.
It can be seen that it is the same as (j). In other words, conventional YC
Patterns that could not be separated by the separation device can be completely YC separated by the device of the present invention.

(Embodiment 2) An embodiment of the invention described in claim 2 of the present invention will be described below with reference to FIG.

In FIG. 5, 201 is a composite video signal 20.
A delay circuit for delaying 0 by 1 horizontal period, 202 is a bandpass filter circuit which receives the composite video signal 200 as an input, 2
Reference numeral 03 is a bandpass filter circuit that receives the output signal of the delay circuit 201, 204 is a C level detection circuit that detects the level of the color signal, and 205 is C correlation detection that receives the output signals of the bandpass filter circuits 202 and 203. A circuit, 206 is a delay circuit that delays the input signal by one horizontal period, 207 and 208 are inverting circuits that invert the input signal,
209 is an arithmetic circuit that subtracts the input signal and outputs a signal whose amplitude is halved. 210 and 211 are switch circuits 21.
A switch determination circuit for generating switching control signals 2 and 213, 212 and 213 are switch circuits that switch the flow of signals, and 214 is a three-line comb that performs calculation using the output signals of the switch circuits 212 and 213 and the inverting circuit 207 as inputs. An arithmetic operation circuit 215 subtracts an input signal and outputs a luminance signal output 217. A subtraction circuit 216 receives the output signal of the 3-line comb arithmetic operation circuit 214 as an input for filtering and outputs a color signal 218.
Reference numeral 9 is a DC detection circuit which receives the composite video signal 200 and the output signal of the delay circuit 201 and detects the level of the DC component by calculating the difference between the two signals, and 220 is the DC detection circuit 2
A DC level amplitude detection circuit for removing the frequency component of the color subcarrier from the output signal of 19 and detecting the amplitude thereof, 22
Reference numeral 1 is a DC correlation detection circuit that determines whether there is correlation or not according to the output signal of the DC level amplitude detection circuit 220.

The operation of the 2-line YC separation device configured as described above will be briefly described. The bandpass filter circuits 202 and 203 are filters that pass a band centered on the color subcarrier frequency, and the C level detection circuit 204 detects the level of the color signal from the output signals of the bandpass filters 202 and 203. The C correlation detection circuit 205 uses the output result of the C level detection circuit 204 to detect the level of the color signal, determines that there is a correlation when the color signal is input, and determines that there is no correlation otherwise.

Regarding the DC component, the DC level detection circuit 219 subtracts the composite video signal 200 and the output signal of the delay circuit 201, and the DC level amplitude detection circuit detects the level of the DC component. From the result of the DC level amplitude detection circuit 220, the DC correlation detection circuit 221 determines that there is a correlation when the DC component is input, and determines that there is no correlation otherwise. The luminance correlation is determined by the output signal of the DC correlation detection circuit 221.

The switch decision circuits 210 and 211 are the output signals of the C correlation detection circuit 205, the output signals of the DC correlation detection circuit 221, the C correlation detection circuit 205, and the DC correlation detection circuit 2.
The output signal of the delay circuit 206 which receives the output signal of 21 is input, and the switching control signal is generated by the logic as shown in FIG. 2 to switch the output signals of the switch circuits 212 and 213. In FIG. 2, (a) shows the switch circuit 21.
2 shows a logic table of the output signal 243 of No. 2 and (b) shows a logic table of the output signal 244 of the switch circuit 213. 230 is the output signal of the DC correlation detection circuit 221;
Reference numeral 31 is a signal obtained by delaying 230 by one horizontal period by the delay circuit 206, 232 is a signal obtained by delaying 233 by one horizontal period by the delay circuit 206, and 233 is an output signal of the C correlation detection circuit 205. The output signals 243 and 2 of the switch circuits 212 and 213 are set according to the combination of the signals of 230, 231, 232 and 233 where 1 is set to have a correlation and 0 is set to have no correlation.
44 is switched to any one of the output signal 240 of the inverting circuit 208, the output signal 241 of the bandpass filter 203, and the arithmetic circuit 209.

The 3-line comb arithmetic circuit 214 is the circuit shown in FIG. 3, which is a filter originally developed for the 3-line comb arithmetic circuit. Here, the input signal is the switch circuit 212, the output signal 243, and the switch circuit 213. Of the output signal 244 and the output signal 245 of the inverting circuit 207 are input.

The subtraction circuit 215 subtracts the output signal of the delay circuit 201 and the output signal of the 3-line comb operation circuit 214 and outputs a luminance signal output 217. Also, 3
The output signal of the line comb calculation circuit 214 is filtered by the filter circuit 216, and the result is output as the color signal output 21.
Output as 8.

(Embodiment 3) An embodiment of the invention described in claim 3 of the present invention will be described below with reference to FIG.

In FIG. 5, 301 is a composite video signal 30.
A delay circuit that delays 0 by 1 horizontal period, 302 is a bandpass filter circuit that receives the composite video signal 300 as input, 3
Reference numeral 03 is a bandpass filter circuit that receives the output signal of the delay circuit 301, 304 is a C level detection circuit that detects the level of the color signal, and 305 is C correlation detection that receives the output signals of the bandpass filter circuits 302 and 303. A circuit, 306 is a delay circuit that delays the input signal by one horizontal period, 307 and 308 are inverting circuits that invert the input signal,
Reference numeral 309 denotes an arithmetic circuit that subtracts the input signal and outputs a signal obtained by halving the amplitude. Reference numerals 310 and 311 denote switch circuits 31.
A switch determination circuit for generating switching control signals of 2, 313, 312, 313 is a switch circuit for switching the flow of signals, 314 is a three-line comb for performing calculation using the output signals of the switch circuits 312, 313, and the inverting circuit 307 as inputs. An arithmetic circuit 315 subtracts an input signal and outputs a luminance signal output 317. A subtraction circuit 316 receives the output signal of the 3-line comb arithmetic circuit 314 as an input for filtering and outputs a color signal 318.
Reference numeral 9 is a DC detection circuit that receives the composite video signal 300 and the output signal of the delay circuit 301 and detects the level of the DC component by calculating the difference between the two signals, and 320 is the DC detection circuit 3.
A DC level amplitude detection circuit for removing the frequency component of the color subcarrier from the output signal of 19 and detecting the amplitude thereof, 32
Reference numeral 3 is a multi-burst detection circuit that allows the output signal of the DC level amplitude detection circuit to pass therethrough, and reference numeral 324 is a Y correlation detection circuit that receives the output signals of the bandpass filter circuits 302 and 303.

The operation of the 2-line YC separation device configured as described above will be briefly described. The bandpass filter circuits 302 and 303 are filters that pass a band centered on the color subcarrier frequency, and the C level detection circuit 304 detects the level of the color signal from the output signals of the bandpass filters 302 and 303. The C correlation detection circuit 305 uses the result of detecting the level of the color signal in the C level detection circuit 304 and the output result of the multi-burst detection circuit to determine that there is a correlation when the color signal is input, and otherwise correlates. Judge as none.

Regarding the DC component, the DC level detection circuit 319 subtracts the composite video signal 300 and the output signal of the delay circuit 301, and the DC level amplitude detection circuit detects the level of the DC component. The multi-burst detection circuit is turned on by the output signal of the DC level amplitude detection circuit, and the output signal of the DC level amplitude detection circuit is added to the C correlation detection circuit to control so as to strengthen the color correlation.

On the other hand, the Y correlation detection circuit 324 is a circuit for detecting the luminance signal from the output signals of the band-pass filters 302 and 303, and judges that there is a correlation when the luminance signal is input, and judges that there is no correlation otherwise. Then, the luminance correlation is judged.

The switch decision circuits 310 and 311 are output signals of the C correlation detection circuit 305, output signals of the DC correlation detection circuit 321, the C correlation detection circuit 305, and the Y correlation detection circuit 32.
The output signal of the delay circuit 306 whose input is the output signal of No. 4 is input, and a switching control signal is generated by the logic as shown in FIG. 2 to switch the output signals of the switch circuits 312 and 313. In FIG. 2, (a) shows the switch circuit 312.
4B shows a logic table of the output signal 343 of the switch circuit 313, and FIG. 9B shows a logic table of the output signal 344 of the switch circuit 313. 330 is an output signal of the Y correlation detection circuit 324, 331
Is a signal obtained by delaying 330 by one horizontal period by the delay circuit 306, 332 is a signal obtained by delaying 333 by one horizontal period by the delay circuit 306, and 333 is an output signal of the C correlation detection circuit 305. 1 if there is a correlation, 3 if 0 if there is no correlation
By combining the signals of 30, 331, 332, 333,
Output signals 343, 344 of the switch circuits 312, 313
Is switched to any one of the output signal 340 of the inverting circuit 308, the output signal 341 of the band pass filter 303, and the arithmetic circuit 309.

The 3-line comb arithmetic circuit 314 is the circuit shown in FIG. 3, which is a filter originally developed for the 3-line comb arithmetic circuit. Here, the input signal is the switch circuit 312, the output signal 343, and the switch circuit 313. Of the output signal 344 and the output signal 345 of the inverting circuit 307 are input.

The subtraction circuit 315 subtracts the output signal of the delay circuit 301 and the output signal of the 3-line comb operation circuit 314 and outputs a luminance signal output 317. Also, 3
The output signal of the line comb operation circuit 314 is filtered by the filter circuit 316, and the result is output as the color signal output 31.
Output as 8.

(Embodiment 4) An embodiment of the invention described in claim 4 of the present invention will be described below with reference to FIG.

In FIG. 7, 401 is a composite video signal 40.
A delay circuit that delays 0 by 1 horizontal period, 402 is a bandpass filter circuit that receives the composite video signal 400 as input, 4
Reference numeral 03 is a bandpass filter circuit that receives the output signal of the delay circuit 401, 404 is a C level detection circuit that detects the level of the color signal, and 405 is C correlation detection that receives the output signals of the bandpass filter circuits 402 and 403. A circuit, 406 is a delay circuit that delays the input signal by one horizontal period, 407 and 408 are inverting circuits that invert the input signal,
Reference numeral 409 is an arithmetic circuit that subtracts the input signal and outputs a signal whose amplitude is halved, and 410 and 411 are switch circuits 41.
A switch determination circuit for generating switching control signals 2 and 413, 412 and 413 are switch circuits that switch the flow of signals, 414 is a three-line comb that performs calculation using the output signals of the switch circuits 412 and 413 and the inverting circuit 407 as inputs. An arithmetic circuit 415 subtracts an input signal and outputs a luminance signal output 417. A subtraction circuit 416 receives the output signal of the 3-line comb arithmetic circuit 414 as an input for filtering and outputs a color signal 418.
Reference numeral 9 is a DC detection circuit that receives the composite video signal 400 and the output signal of the delay circuit 401 as an input and detects the level of the DC component by taking the difference between the two signals and 420 is the DC detection circuit 4
A DC level amplitude detection circuit for removing the frequency component of the color subcarrier from the output signal of 19 and detecting the amplitude thereof;
2 is a DC adaptive circuit that determines whether there is correlation according to the output signal of the DC detection circuit, and 423 is turned on when the output result of the DC adaptation circuit 422 is correlated, and the output signal of the DC level amplitude detection circuit is passed. A multi-burst detection circuit 424 that is turned off when there is no correlation is a Y correlation detection circuit that receives the output signals of the bandpass filter circuits 402 and 403 as input.

The operation of the 2-line YC separation device configured as described above will be briefly described. The bandpass filter circuits 402 and 403 are filters that pass a band centered on the color subcarrier frequency, and the C level detection circuit 404 detects the level of the color signal from the output signals of the bandpass filters 402 and 403. The C correlation detection circuit 405 uses the result of detecting the color signal level in the C level detection circuit 404 and the output result of the multi-burst detection circuit, determines that there is a correlation when the color signal is input, and correlates other than that. Judge as none.

Regarding the DC component, the DC level detection circuit 419 subtracts the composite video signal 400 and the output signal of the delay circuit 401, and the DC level amplitude detection circuit detects the level of the DC component. The DC adaptation circuit 422 receives the output signal of the DC level detection circuit and detects the correlation before passing through the 2-input bandpass filter. When the DC adaptation circuit determines that there is a correlation, the multi-burst detection circuit is turned on, and the output signal of the DC level amplitude detection circuit is added to the C correlation detection circuit to control so that the color correlation is enhanced.

On the other hand, the Y correlation detection circuit 424 is a circuit for detecting the luminance signal from the output signals of the band-pass filters 402 and 403. When the luminance signal is input, it is determined that there is a correlation, and otherwise the luminance is regarded as no correlation. Judge the correlation.

The switch decision circuits 410 and 411 output the output signal of the C correlation detection circuit 405, the output signal of the Y correlation detection circuit 424 and the C correlation detection circuit 405 and the Y correlation detection circuit 424.
The output signal of the delay circuit 406, which receives the output signal of FIG. 2 as an input, is used as an input to generate a switching control signal by the logic shown in FIG. 2 to switch the output signals of the switch circuits 412 and 413. In FIG. 2, (a) shows a logic table of the output signal 443 of the switch circuit 412, and (b) shows a logic table of the output signal 444 of the switch circuit 413. 430 is an output signal of the DC correlation detection circuit 421, 43
Reference numeral 1 is a signal obtained by delaying 430 by one horizontal period by the delay circuit 406, 432 is a signal obtained by delaying 433 by one horizontal period by the delay circuit 406, and 433 is an output signal of the C correlation detection circuit 405. 4 if there is a correlation and 1 if there is no correlation
By combining the signals of 30, 431, 432, 433,
Output signals 443 and 444 of the switch circuits 412 and 413
Is switched to any one of the output signal 440 of the inverting circuit 408, the output signal 441 of the bandpass filter 403, and the arithmetic circuit 409.

The 3-line comb arithmetic circuit 414 is the circuit shown in FIG. 3, which is a filter originally developed for the 3-line comb arithmetic circuit. Here, the input signal is the switch circuit 412, the output signal 443, and the switch circuit 413. Of the output signal 444 and the output signal 445 of the inverting circuit 407 are input.

The subtraction circuit 415 subtracts the output signal of the delay circuit 401 and the output signal of the 3-line comb operation circuit 414, and outputs a luminance signal output 417. Also, 3
The output signal of the line comb calculation circuit 414 is filtered by the filter circuit 416, and the result is color signal output 41.
Output as 8.

(Embodiment 5) An embodiment of the invention described in claim 5 of the present invention will be described below with reference to FIG.

In FIG. 8, 501 is a composite video signal 50.
A delay circuit that delays 0 by 1 horizontal period, 502 is a bandpass filter circuit that inputs the composite video signal 500, and 5
Reference numeral 03 is a bandpass filter circuit that receives the output signal of the delay circuit 501, 504 is a C level detection circuit that detects the level of the color signal, and 505 is C correlation detection that receives the output signals of the bandpass filter circuits 502 and 503. A circuit, 506 is a delay circuit that delays the input signal by one horizontal period, 507 and 508 are inverting circuits that invert the input signal,
Reference numeral 509 denotes an arithmetic circuit for subtracting the input signal and outputting a signal obtained by halving the amplitude. 510, 511 denote switch circuits 51.
A switch determination circuit for generating the switching control signals of 2, 513, 512 and 513 are switch circuits that switch the flow of signals, 514 is a three-line comb that performs calculation by using the output signals of the switch circuits 512 and 513 and the inverting circuit 507 as inputs. An arithmetic circuit 515 subtracts an input signal and outputs a luminance signal output 517. A subtraction circuit 516 receives the output signal of the 3-line comb arithmetic circuit 514 as an input for filtering and outputs a color signal 518.
Reference numeral 9 is a DC detection circuit that receives the composite video signal 500 and the output signal of the delay circuit 501 as an input, detects the difference between the two signals, and detects the level of the DC component, and 520 is the DC detection circuit 5.
A DC level amplitude detection circuit for removing the frequency component of the color subcarrier from the output signal of 19 and detecting the amplitude thereof;
1 is a DC correlation detection circuit that determines whether there is correlation according to the output signal of the DC level amplitude detection circuit 520, 524 is a Y correlation detection circuit that receives the output signals of the bandpass filter circuits 502 and 503, and 525 is an input It is an AND circuit that takes the logical product of signals.

The operation of the 2-line YC separation device constructed as described above will be briefly described. The bandpass filter circuits 502 and 503 are filters that pass a band centered on the color subcarrier frequency, and the C level detection circuit 504 detects the level of the color signal from the output signals of the bandpass filters 502 and 503. The C correlation detection circuit 505 uses the result of detecting the level of the color signal by the C level detection circuit 504, determines that there is a correlation when the color signal is input, and determines that there is no correlation otherwise.

Regarding the DC component, the DC level detection circuit 519 subtracts the composite video signal 500 and the output signal of the delay circuit 501, and the DC level amplitude detection circuit detects the level of the DC component.

On the other hand, the Y correlation detection circuit 524 is a circuit for detecting a luminance signal from the output signals of the band-pass filters 502 and 503. When the luminance signal is input, it is determined that there is a correlation, and otherwise the correlation is determined to be non-correlation. To do. From the result of the DC level amplitude detection circuit 520, the DC correlation detection circuit 521 determines that there is a correlation when a DC component is input, and otherwise determines that there is no correlation. This DC correlation detection circuit 5
The AND circuit 525 obtains the logical product of the output signal of the reference numeral 21 and the output signal of the Y correlation detection circuit 524 to determine the luminance correlation.

The switch decision circuits 510 and 511 input the output signal of the C correlation detection circuit 505, the output signal of the AND circuit 525 and the output signal of the delay circuit 506 which receives the output signals of the C correlation detection circuit 505 and the AND circuit 525, respectively. As a result, a switching control signal is generated by the logic shown in FIG. 2 to switch the output signals of the switch circuits 512 and 513. In FIG. 2, (a) shows a logic table of the output signal 543 of the switch circuit 512, and (b) shows the switch circuit 5
13 shows a logic table of 13 output signals 544. 53
0 is the output signal of the DC correlation detection circuit 521, 531 is 53
0 signal delayed by one horizontal period by the delay circuit 506, 53
Reference numeral 2 is a signal obtained by delaying 533 by one horizontal period by the delay circuit 506, and reference numeral 533 is an output signal of the C correlation detection circuit 505.
When there is a correlation, 1 is set, and when there is no correlation, 0 is set to 530, 5
The output signals 543 and 544 of the switch circuits 512 and 513 are converted to the output signal 540 of the inverting circuit 508 and the bandpass filter 50 by the combination of the signals of 31, 532 and 533.
3 of the output signal 541 and the signal of the arithmetic circuit 509.

The 3-line comb arithmetic circuit 514 is the circuit shown in FIG. 3, which is a filter originally developed for the 3-line comb arithmetic circuit. Here, the input signal is the switch circuit 512, the output signal 543, and the switch circuit 513. Of the output signal 544 of the inverting circuit 507 and the output signal 545 of the inverting circuit 507 are input.

The subtraction circuit 515 subtracts the output signal of the delay circuit 501 and the output signal of the 3-line comb operation circuit 514 and outputs a luminance signal output 517. Also, 3
The output signal of the line comb calculation circuit 514 is filtered by the filter circuit 516, and the result is color signal output 51.
Output as 8.

(Embodiment 6) An embodiment of the invention described in claim 6 of the present invention will be described below with reference to FIG.

In FIG. 5, reference numeral 601 denotes a composite video signal 60.
A delay circuit that delays 0 by 1 horizontal period, 602 is a bandpass filter circuit that receives the composite video signal 600 as input, 6
Reference numeral 03 is a bandpass filter circuit that receives the output signal of the delay circuit 601 as input, 604 is a C level detection circuit that detects the level of the color signal, and 605 is C correlation detection that receives the output signals of the bandpass filter circuits 602 and 603. A circuit, 606 is a delay circuit that delays the input signal by one horizontal period, 607 and 608 are inverting circuits that invert the input signal,
Reference numeral 609 denotes an arithmetic circuit that subtracts the input signal and outputs a signal whose amplitude is halved.
A switch determination circuit for generating the switching control signals of 2 and 613, 612 and 613 are switch circuits that switch the flow of signals, and 614 is a three-line comb that performs calculation by using the output signals of the switch circuits 612 and 613 and the inverting circuit 607 as inputs. An arithmetic circuit, 615 is a subtraction circuit which subtracts an input signal and outputs a luminance signal output 617, 616 is a filter circuit which receives the output signal of the three-line comb arithmetic circuit 614 as input, performs filtering, and outputs a color signal 618, 62
Reference numeral 4 is a Y correlation detection circuit that receives the output signals of the bandpass filter circuits 602 and 603, and reference numeral 626 is a correlation spreading circuit that extends the input signal to a non-correlated state in the time axis direction.

The operation of the 2-line YC separation device constructed as described above will be briefly described. The bandpass filter circuits 602 and 603 are filters that pass a band centered on the color subcarrier frequency, and the C level detection circuit 604 detects the level of the color signal from the output signals of the bandpass filters 602 and 603. The C correlation detection circuit 605 uses the result of detecting the level of the color signal by the C level detection circuit 604, determines that there is a correlation when the color signal is input, and otherwise determines the color correlation as no correlation.

On the other hand, the Y correlation detection circuit 624 is a circuit for detecting a luminance signal from the output signals of the band-pass filters 602 and 603. When the luminance signal is input, it is determined that there is a correlation, and otherwise the luminance is regarded as no correlation. Judge the correlation.

Next, the correlation spreading circuit 606 will be described with reference to FIG. When there is an input like (a) (b)
When sampling at such timing, the output result is determined by the value at that moment. The results are shown in (c). Therefore, a signal (d) obtained by shifting (c) in the time axis direction is created, and the logical product of (c) and (d) is obtained and used as the output signal (e). By doing so, it is possible to prevent the fluttering of the correlation detection signal.

The switch decision circuits 610, 611 obtain the output signal of the C correlation detection circuit 605 by inputting it to the correlation spreading circuit 626 and the output signal of the Y correlation detection circuit 624 by inputting it to the correlation spreading circuit 626. The obtained signal and the output signal of the C correlation detection circuit 605 are input to the correlation spreading circuit 626, and the output signal of the Y correlation detection circuit 624 is input to the correlation spreading circuit 626. 2 with the output signal of the delay circuit 606 as an input.
A switching control signal is generated by such logic to switch the output signals of the switch circuits 612 and 613.
In FIG. 2, (a) shows the output signal 643 of the switch circuit 612.
2B shows a logic table of the output signal 644 of the switch circuit 613. 630 is DC
The output signal of the correlation detection circuit 621, 631 is a signal obtained by delaying 630 by the delay circuit 606 for one horizontal period, and 632 is 63.
3 delayed by the delay circuit 606 for one horizontal period, 63
Reference numeral 3 is an output signal of the C correlation detection circuit 605. 630, 631, 6 as 1 when there is a correlation and 0 when there is no correlation
The switch circuit 61 is formed by combining the signals of 32 and 633.
The output signals 643 and 644 of 2, 613 are inverted to the inverting circuit 608
Output signal 640, the output signal 641 of the bandpass filter 603, and the arithmetic circuit 609.

The 3-line comb arithmetic circuit 614 is the circuit shown in FIG. 3, and is a filter originally developed for the 3-line comb arithmetic circuit. Here, the input signal is the switch circuit 612, the output signal 643, and the switch circuit 613. Of the output signal 644 and the output signal 645 of the inverting circuit 607 are input.

The subtraction circuit 615 subtracts the output signal of the delay circuit 601 and the output signal of the 3-line comb operation circuit 614 and outputs a luminance signal output 617. Also, 3
The output signal of the line comb calculation circuit 614 is filtered by the filter circuit 616, and the result is output as the color signal output 61.
Output as 8.

[0066]

According to the present invention, it is possible to provide a 2-line YC separation device which has less malfunctions, performs more accurate YC separation, and has less horizontal period delay circuits.

[Brief description of drawings]

FIG. 1 is a block configuration diagram of a 2-line YC separation device according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a logic table of a 2-line YC separation device.

FIG. 3 is a block configuration diagram of a 3-line comb arithmetic circuit.

FIG. 4 is an operation waveform diagram of the 2-line YC separation device according to the first embodiment of the present invention.

FIG. 5 is a block configuration diagram of a 2-line YC separation device according to a second embodiment of the present invention.

FIG. 6 is a block configuration diagram of a 2-line YC separation device according to a third embodiment of the present invention.

FIG. 7 is a block configuration diagram of a 2-line YC separation device according to a fourth embodiment of the present invention.

FIG. 8 is a block configuration diagram of a 2-line YC separation device according to a fifth embodiment of the present invention.

FIG. 9 is a block configuration diagram of a 2-line YC separation device according to a sixth embodiment of the present invention.

FIG. 10 is an operation waveform diagram of a correlation spreading circuit according to the sixth embodiment of the present invention.

FIG. 11 is a block configuration diagram of a conventional 2-line YC separation device.

FIG. 12 is an operation waveform diagram of a conventional 2-line YC separation device.

[Explanation of symbols]

100 Composite video signal input terminal 101, 106 1 horizontal line delay circuit 102, 103 band pass filter circuit 105 C correlation detection circuit 124 Y correlation detection circuit 121 DC correlation detection circuit 123 Multiburst detection circuit 110,111 switch decision circuit 112,113 switch circuit 107, 108 Inversion circuit 109 arithmetic circuit 114 3 line comb arithmetic circuit 115 Subtraction circuit 116 Filter circuit

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) H04N 9/78

Claims (6)

(57) [Claims] 1. A first delay circuit that delays an input composite video signal by an integral multiple of a horizontal period, a first bandpass filter circuit that receives the input video signal, and the first delay circuit. A second bandpass filter circuit that receives the output signal of the first bandpass filter circuit and a Y correlation detection circuit that receives the output signals of the first and second bandpass filter circuits.
A C level detection circuit that receives the output signals of the first and second bandpass filter circuits, a C correlation detection circuit that receives the output signal of the C level detection circuit, and an output signal of the Y correlation detection circuit. For a horizontal period, a third delay circuit for delaying the output signal of the C correlation detection circuit for a horizontal period, and a first delay circuit for inputting the output signal of the first bandpass filter circuit. An inverting circuit, an arithmetic circuit that receives the output signals of the first and second bandpass filter circuits, an output signal of the Y correlation detection circuit and the C correlation detection circuit, and the second and third delay circuits. A first switch determination circuit that receives an output signal, output signals of the Y correlation detection circuit and C correlation detection circuit, and the second and third
Second switch determination circuit having the output signal of the delay circuit as an input, a second inverting circuit having the output signal of the second bandpass filter circuit as an input, the output signal of the arithmetic circuit and the second Of the inverting circuit and the output signal of the second bandpass filter circuit are switched by the output signal of the first switch determination circuit, the output signal of the arithmetic circuit and the second switch circuit. A second switch circuit that switches the output signal of the bandpass filter circuit according to the output signal of the second switch determination circuit, the output signal of the first inverting circuit, and the output signals of the first and second switch circuits. A 3-line comb operation circuit, a subtraction circuit having an output signal of the first delay circuit and an output signal of the 3-line comb operation circuit as inputs, and the 3-line In addition to the configuration of the filter circuit that receives the output signal of the digital operation circuit, the input composite video signal and the output signal of the first delay circuit are input, and the difference between the two signals is calculated to detect the level of the DC component. And a DC level amplitude detection circuit that removes the frequency component of the color subcarrier from the output signal of the DC detection circuit and detects the amplitude thereof, and there is a correlation according to the output signal of the DC level amplitude detection circuit, A multi-burst detection circuit that determines whether there is no correlation, and a DC adaptive circuit that determines whether there is correlation according to the output signal of the DC detection circuit, and a DC that determines whether there is correlation depending on the output signal of the DC level amplitude detection circuit A correlation detection circuit, and an AND circuit that takes the logical product of the output signal of the DC correlation detection circuit and the output signal of the Y correlation detection circuit.
According to the output of the adaptation circuit, it is determined whether the output signal of the DC level amplitude detection circuit is added to the C correlation detection circuit. For the color, the C correlation detection circuit detects the C correlation, and the output signal of the C correlation detection circuit. Is used as the color correlation selection signal of the switch determination circuit, and for the luminance, the output signal of the AND circuit which is the logical product of the output signal of the Y correlation detection circuit and the DC correlation detection circuit is used as the selection signal of the luminance correlation of the switch determination circuit. A 2-line YC separation device characterized by being used. 2. A first delay circuit that delays an input composite video signal by an integral multiple of a horizontal period, a first bandpass filter circuit that receives the input video signal, and the first delay circuit. A second bandpass filter circuit that receives the output signal of the first bandpass filter circuit and a Y correlation detection circuit that receives the output signals of the first and second bandpass filter circuits.
A C level detection circuit that receives the output signals of the first and second bandpass filter circuits, a C correlation detection circuit that receives the output signal of the C level detection circuit, and an output signal of the Y correlation detection circuit. For a horizontal period, a third delay circuit for delaying the output signal of the C correlation detection circuit for a horizontal period, and a first delay circuit for inputting the output signal of the first bandpass filter circuit. An inverting circuit, an arithmetic circuit that receives the output signals of the first and second bandpass filter circuits, an output signal of the Y correlation detection circuit and the C correlation detection circuit, and the second and third delay circuits. A first switch determination circuit that receives an output signal, output signals of the Y correlation detection circuit and C correlation detection circuit, and the second and third
Second switch determination circuit having the output signal of the delay circuit as an input, a second inverting circuit having the output signal of the second bandpass filter circuit as an input, the output signal of the arithmetic circuit and the second Of the inverting circuit and the output signal of the second bandpass filter circuit are switched by the output signal of the first switch determination circuit, the output signal of the arithmetic circuit and the second switch circuit. A second switch circuit that switches the output signal of the bandpass filter circuit according to the output signal of the second switch determination circuit, the output signal of the first inverting circuit, and the output signals of the first and second switch circuits. A 3-line comb operation circuit, a subtraction circuit having an output signal of the first delay circuit and an output signal of the 3-line comb operation circuit as inputs, and the 3-line In addition to the configuration of the filter circuit that receives the output signal of the digital operation circuit, the input composite video signal and the output signal of the first delay circuit are input, and the difference between the two signals is calculated to detect the level of the DC component. And a DC level amplitude detection circuit that removes the frequency component of the color subcarrier from the output signal of the DC detection circuit and detects the amplitude thereof. Instead of the Y correlation detection circuit, a DC level amplitude detection circuit is provided. A two-line YC separation device comprising a DC correlation detection circuit for determining whether there is correlation or not according to an output signal of the circuit, and using the output of the DC correlation detection circuit as a selection signal for the luminance correlation of the switch determination circuit. . 3. A first delay circuit that delays an input composite video signal by an integral multiple of a horizontal period, a first bandpass filter circuit that receives the input video signal, and the first delay circuit. A second bandpass filter circuit that receives the output signal of the first bandpass filter circuit and a Y correlation detection circuit that receives the output signals of the first and second bandpass filter circuits.
A C level detection circuit that receives the output signals of the first and second bandpass filter circuits, a C correlation detection circuit that receives the output signal of the C level detection circuit, and an output signal of the Y correlation detection circuit. For a horizontal period, a third delay circuit for delaying the output signal of the C correlation detection circuit for a horizontal period, and a first delay circuit for inputting the output signal of the first bandpass filter circuit. An inverting circuit, an arithmetic circuit that receives the output signals of the first and second bandpass filter circuits, an output signal of the Y correlation detection circuit and the C correlation detection circuit, and the second and third delay circuits. A first switch determination circuit that receives an output signal, output signals of the Y correlation detection circuit and C correlation detection circuit, and the second and third
Second switch determination circuit having the output signal of the delay circuit as an input, a second inverting circuit having the output signal of the second bandpass filter circuit as an input, the output signal of the arithmetic circuit and the second Of the inverting circuit and the output signal of the second bandpass filter circuit are switched by the output signal of the first switch determination circuit, the output signal of the arithmetic circuit and the second switch circuit. A second switch circuit that switches the output signal of the bandpass filter circuit according to the output signal of the second switch determination circuit, the output signal of the first inverting circuit, and the output signals of the first and second switch circuits. A 3-line comb operation circuit, a subtraction circuit having an output signal of the first delay circuit and an output signal of the 3-line comb operation circuit as inputs, and the 3-line In addition to the configuration of the filter circuit that receives the output signal of the digital operation circuit, the input composite video signal and the output signal of the first delay circuit are input, and the difference between the two signals is calculated to detect the level of the DC component. And a DC level amplitude detection circuit that removes the frequency component of the color subcarrier from the output signal of the DC detection circuit and detects the amplitude thereof, and there is a correlation according to the output signal of the DC level amplitude detection circuit, The multi-burst detection circuit for determining the absence is provided, the output of the multi-burst detection circuit is added to the C correlation detection circuit to determine C correlation, and the output signal of the C correlation detection circuit is used as the color correlation selection signal of the switch determination circuit. A 2-line YC separation device characterized by being used. 4. A first delay circuit that delays an input composite video signal by an integral multiple of a horizontal period, a first bandpass filter circuit that receives the input video signal, and the first delay circuit. A second bandpass filter circuit that receives the output signal of the first bandpass filter circuit and a Y correlation detection circuit that receives the output signals of the first and second bandpass filter circuits.
A C level detection circuit that receives the output signals of the first and second bandpass filter circuits, a C correlation detection circuit that receives the output signal of the C level detection circuit, and an output signal of the Y correlation detection circuit. For a horizontal period, a third delay circuit for delaying the output signal of the C correlation detection circuit for a horizontal period, and a first delay circuit for inputting the output signal of the first bandpass filter circuit. An inverting circuit, an arithmetic circuit that receives the output signals of the first and second bandpass filter circuits, an output signal of the Y correlation detection circuit and the C correlation detection circuit, and the second and third delay circuits. A first switch determination circuit that receives an output signal, output signals of the Y correlation detection circuit and C correlation detection circuit, and the second and third
Second switch determination circuit having the output signal of the delay circuit as an input, a second inverting circuit having the output signal of the second bandpass filter circuit as an input, the output signal of the arithmetic circuit and the second Of the inverting circuit and the output signal of the second bandpass filter circuit are switched by the output signal of the first switch determination circuit, the output signal of the arithmetic circuit and the second switch circuit. A second switch circuit that switches the output signal of the bandpass filter circuit according to the output signal of the second switch determination circuit, the output signal of the first inverting circuit, and the output signals of the first and second switch circuits. A 3-line comb operation circuit, a subtraction circuit having an output signal of the first delay circuit and an output signal of the 3-line comb operation circuit as inputs, and the 3-line In addition to the configuration of the filter circuit that receives the output signal of the digital operation circuit, the input composite video signal and the output signal of the first delay circuit are input, and the difference between the two signals is calculated to detect the level of the DC component. And a DC level amplitude detection circuit that removes the frequency component of the color subcarrier from the output signal of the DC detection circuit and detects the amplitude thereof, and there is a correlation according to the output signal of the DC level amplitude detection circuit, An output signal of the DC level amplitude detection circuit is provided, which includes a multi-burst detection circuit for determining absence and a DC adaptation circuit for determining presence or absence of correlation according to the output signal of the DC detection circuit. Is added to the C correlation detection circuit, and C is detected by the C correlation detection circuit.
Correlation detection is performed, and the output of the C correlation detection circuit is used as a color correlation selection signal of the switch determination circuit.
Line YC separation device. 5. A first delay circuit that delays an input composite video signal by an integral multiple of a horizontal period, a first bandpass filter circuit that receives the input video signal, and the first delay circuit. A second bandpass filter circuit that receives the output signal of the first bandpass filter circuit and a Y correlation detection circuit that receives the output signals of the first and second bandpass filter circuits.
A C level detection circuit that receives the output signals of the first and second bandpass filter circuits, a C correlation detection circuit that receives the output signal of the C level detection circuit, and an output signal of the Y correlation detection circuit. For a horizontal period, a third delay circuit for delaying the output signal of the C correlation detection circuit for a horizontal period, and a first delay circuit for inputting the output signal of the first bandpass filter circuit. An inverting circuit, an arithmetic circuit that receives the output signals of the first and second bandpass filter circuits, an output signal of the Y correlation detection circuit and the C correlation detection circuit, and the second and third delay circuits. A first switch determination circuit that receives an output signal, output signals of the Y correlation detection circuit and C correlation detection circuit, and the second and third
Second switch determination circuit having the output signal of the delay circuit as an input, a second inverting circuit having the output signal of the second bandpass filter circuit as an input, the output signal of the arithmetic circuit and the second Of the inverting circuit and the output signal of the second bandpass filter circuit are switched by the output signal of the first switch determination circuit, the output signal of the arithmetic circuit and the second switch circuit. A second switch circuit that switches the output signal of the bandpass filter circuit according to the output signal of the second switch determination circuit, the output signal of the first inverting circuit, and the output signals of the first and second switch circuits. A 3-line comb operation circuit, a subtraction circuit having an output signal of the first delay circuit and an output signal of the 3-line comb operation circuit as inputs, and the 3-line In addition to the configuration of the filter circuit that receives the output signal of the digital operation circuit, the input composite video signal and the output signal of the first delay circuit are input, and the difference between the two signals is calculated to detect the level of the DC component. And a DC level amplitude detection circuit that removes the frequency component of the color subcarrier from the output signal of the DC detection circuit and detects the amplitude thereof, and there is a correlation according to the output signal of the DC level amplitude detection circuit, A DC correlation detection circuit for determining whether there is no
Two lines characterized by being provided with an AND circuit that takes the logical product of the output signal of the correlation detection circuit and the output signal of the Y correlation detection circuit, and the output of the AND circuit is used as the selection signal of the luminance correlation of the switch determination circuit. YC separation device. 6. A first delay circuit that delays an input composite video signal by an integral multiple of a horizontal period, a first bandpass filter circuit that receives the input video signal, and the first delay circuit. A second bandpass filter circuit that receives the output signal of the first bandpass filter circuit and a Y correlation detection circuit that receives the output signals of the first and second bandpass filter circuits.
A C level detection circuit that receives the output signals of the first and second bandpass filter circuits, a C correlation detection circuit that receives the output signal of the C level detection circuit, and an output signal of the Y correlation detection circuit. For a horizontal period, a third delay circuit for delaying the output signal of the C correlation detection circuit for a horizontal period, and a first delay circuit for inputting the output signal of the first bandpass filter circuit. An inverting circuit, an arithmetic circuit that receives the output signals of the first and second bandpass filter circuits, an output signal of the Y correlation detection circuit and the C correlation detection circuit, and the second and third delay circuits. A first switch determination circuit that receives an output signal, output signals of the Y correlation detection circuit and C correlation detection circuit, and the second and third
Second switch determination circuit having the output signal of the delay circuit as an input, a second inverting circuit having the output signal of the second bandpass filter circuit as an input, the output signal of the arithmetic circuit and the second Of the inverting circuit and the output signal of the second bandpass filter circuit are switched by the output signal of the first switch determination circuit, the output signal of the arithmetic circuit and the second switch circuit. A second switch circuit that switches the output signal of the bandpass filter circuit according to the output signal of the second switch determination circuit, the output signal of the first inverting circuit, and the output signals of the first and second switch circuits. A 3-line comb operation circuit, a subtraction circuit having an output signal of the first delay circuit and an output signal of the 3-line comb operation circuit as inputs, and the 3-line In addition to the configuration of the filter circuit that receives the output signal of the digital operation circuit, the output signal of the Y correlation detection circuit is delayed for a certain time, and the correlation spreading circuit that extends the signal within that time to the uncorrelated state in time is provided. If the output of the Y correlation detection circuit flutters, the result of the correlation detection is brought into a non-correlated state and used as a selection signal of the switch determination circuit.