JP2667492B2 - Composite television signal generation circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial application field) The present invention multiplexes a luminance signal and a chrominance signal or an additional signal according to the movement of a television image to form a composite television signal. The present invention relates to a composite television signal generation circuit for generating.

(Prior Art) The current color television system uses a composite television signal in which a luminance signal is superimposed on a color subcarrier (chromaticity signal) modulated with a color signal. For example, the NTSC system is described on pages 132 to 141 of the broadcasting system (Japan Broadcasting Corporation, issued on January 20, 1983). The television signal transmission / reception system based on the NTSC system shown in
Figure 10 shows.

In FIG. 10, reference numeral 10 denotes an NTSC encoder on the transmission side. The NTSC encoder supplies R (red), G (green), and B (blue) from a signal source (not shown) such as a camera and a VTR supplied to the encoder 10. Each video signal is supplied to the matrix circuit 11 for a luminance signal Y and color signals I, Q
Is converted to Among them, the Y signal is directly supplied to the addition circuit (Σ) 12. The I and Q signals are low-pass filters (L
After being band-limited by the PFs 13 and 14, they are quadrature-modulated by the carrier signals (frequency is fsc) from the carrier generation circuit 17 in the multipliers 15 and 16 to become chromaticity signals. Each chromaticity signal is supplied to an addition circuit 12, where it is added to the Y signal to form a composite television signal.

On the other hand, reference numeral 18 denotes an NTSC decoder on the receiving side. The composite television signal supplied from the encoder 10 to the decoder 18 is converted by a Y / C separation circuit 19 into a Y signal and a C signal (I signal and Q signal are subjected to quadrature modulation). Color signal).
The separated Y signal is directly supplied to the inverse matrix circuit 20, and the C signal is demodulated into I and Q signals by the multipliers 21 and 22 and the carrier generation circuit 23, and the low pass filter 2
After being band-limited at 4,25, it is supplied to the inverse matrix circuit 20. The inverse matrix circuit 20 converts the Y, I, and Q signals into the original video signals R, C, and B, and outputs the signals to, for example, a monitor (not shown).

As described above, since the luminance signal and the chrominance signal are multiplexed on the transmitting side of the conventional NTSC color television signal, luminance / color (hereinafter, referred to as Y / C) separation processing is required on the receiving side. is there. However, if this processing is simply performed,
Image quality deterioration such as cross color and dot crawl due to incomplete separation occurs. Recently, there is a tendency to use a comb filter having good separation performance for Y / C separation processing, but still the resolution in the oblique direction is not sufficient.

In order to improve such a problem, in recent years, a Y / C separation circuit which detects movement information of a picture and changes a parameter of a filter characteristic has been developed. The configuration of this circuit is
For example, from page 470 of the SMPTE Journal (issued in May 1984)
As described on page 476, for high-definition television signal processing, a motion detection signal is generated by performing an inter-frame operation on a still image, and Y / C separation is performed in accordance with the motion detection signal. It is something to do. Eleventh
The figure shows the configuration of the Y / C separation circuit according to the literature.

In FIG. 11, the composite television signal supplied to the input terminal 26 is supplied to a subtracter 27, an inter-line calculator 28, an inter-frame calculator 29, and a motion detector 30. Line to line calculator
28, the inter-frame calculator 29 sequentially calculates the difference components between lines and frames from the input composite television signal, and outputs of the calculators 28 and 29 are output via gain control circuits 31 and 32, respectively. It is supplied to the adder 32a and is synthesized. The synthesized output obtained here is led out from the output terminal 34 as a color signal C via the horizontal bandpass filter 33 and is also supplied to the subtracter 27. That is, the subtracter 27 extracts the luminance signal Y by subtracting the color signal C from the composite television signal, and the luminance signal Y is derived from the output terminal 35. On the other hand, the motion detector 30 detects a motion amount corresponding to the motion of the image from the input composite television signal, generates a control signal corresponding to the motion amount, and adjusts the gains of the gain control circuits 31 and 32. To control.

That is, when the composite television signal is stationary between frames, the signal is as shown in Figure 12 (a), each frequency component of the luminance signal component y ₁ and chromaticity signal components c ₁ is in a vertical direction spread, because it does not spread in a time direction, it is possible to separate the chrominance signal c ₁ in operation between frames. Conversely, if the composite television signal is moving between frames,
The signal is a luminance signal component y _{1 as} shown in FIG.
Since each frequency component of the chromaticity signal component c ₁ does not spread in the vertical direction but spreads in the time direction, the chromaticity signal c ₁ can be separated by an operation between lines. So, above
In the Y / C separation circuit, in the case of a still image, the gain of the gain control circuit 32 is increased to decrease the gain of the gain control circuit 31, and in the case of a moving image, control opposite to that of the still image is performed. .

By the way, since the Y / C separation circuit having the above configuration performs the separation process in accordance with the motion of the image, it should be able to obtain good Y / C separation characteristics. Assuming that the spectrum does not spread in the direction, the spectrum spread in the vertical direction is large even in the moving image due to the high performance of the TV camera in the actual television image. There is a problem in that crosstalk occurs due to.

On the other hand, in recent years, the EDTV (Extended Def.
inition TV) system is being developed. As one candidate of the EDTV system, there is a wide aspect TV system in which additional information for expanding an aspect ratio is multiplexed into an oblique high-frequency component of a television signal to achieve compatibility with a current receiver. This method is described, for example, in the Technical Report of the Institute of Television Engineers of Japan (August 1988, Vol. 12), pp. 55-60. The additional information multiple spectrum according to this document is
Shown in the figure.

That is, FIG. 13A shows each region in the horizontal direction and the vertical direction when the main signal (luminance signal) and the multiplex signal (additional signal) are multiplexed, and FIG. Each area in the vertical direction is shown. This utilizes the fact that the oblique high frequency component of the luminance signal has a low visual contribution, and is used as a multiplex area. However, if the television signal in which the additional signal is multiplexed in the obliquely wide area is encoded into the NTSC composite television signal, the crosstalk between the Y signal and the C signal generated at the time of the Y / C separation as described above. In addition to this, crosstalk of multiplex signals also occurs, which is not preferable in principle.

(Problems to be Solved by the Invention) As described above, in the conventional motion adaptive Y / C separation circuit, when the NTSC television signal is separated into the Y signal and the C signal, the Y signal and the C signal are used at the time of moving image. Crosstalk occurs. Further, when the additional information is multiplexed in the obliquely high frequency range of the luminance signal, a stroke of the multiplexed signal is further generated.

The present invention has been made in order to solve the above-mentioned problems, and Y / C separation that is accurately adapted to motion can be performed even during a moving image without deteriorating image quality. It is an object of the present invention to provide a composite television signal generation circuit which can prevent crosstalk from occurring even when multiplexing is performed.

[Composition of the Invention] (Means for Solving the Problems) In order to achieve the above object, a composite television signal generation circuit according to the present invention comprises: (1) a composite television signal obtained by multiplexing a luminance signal and a chrominance signal; A motion detecting means for detecting each motion amount of the luminance signal and the color signal; and a selecting means for selecting and outputting a larger one of the motion amounts of the luminance signal and the color signal obtained by this means. Extracting, from the luminance signal, a component equal to or higher than the horizontal boundary frequency with respect to the color signal, extracting a component equal to or lower than the vertical boundary frequency with respect to the color signal from the component, and extracting both components from the motion amount obtained by the selection means. And a first band limiting unit that adds a component equal to or lower than a horizontal boundary frequency with the color signal to the mixed output to limit the luminance signal according to the motion. , The color From the color sub-carrier frequency and the horizontal boundary frequency, extract a component equal to or less than the difference between the color sub-carrier frequency and the vertical boundary frequency from the component, and extract this component and the current color. A second band limiting unit that mixes the signals with a weighting ratio determined according to the amount of motion obtained by the selecting unit, performs quadrature modulation with the color subcarrier, and limits the band of the color signal according to the motion. The first feature is that it further comprises: a multiplexing unit that frequency-multiplexes the luminance signal and the chrominance signal output from the first and second band limiting units to generate a composite television signal.

(2) In a device for generating a composite television signal by multiplexing a luminance signal, a chrominance signal and an additional signal, a component equal to or higher than a boundary frequency in the horizontal direction with the additional signal is extracted from the luminance signal, and an additional signal is extracted from the component. A third band-limiting means for extracting a component equal to or less than the boundary frequency in the vertical direction and the time direction and adding a component equal to or less than the boundary frequency in the horizontal direction to the additional signal to limit the band of the luminance signal; First multiplexing means for frequency-multiplexing the additional signal in a band-limited frequency region of the luminance signal obtained by the means, and motion detecting means for detecting each motion amount of the luminance signal and the chrominance signal obtained by this means. Selecting means for selecting and outputting the larger one of the motion amounts of the luminance signal and the chrominance signal obtained by this means; and a horizontal boundary frequency between the luminance signal obtained by the first multiplexing means and the chrominance signal. Since , A component below the vertical boundary frequency with the color signal is extracted from the component, and both components are mixed at a weighting ratio determined according to the amount of motion obtained by the selection means. A first band limiting unit that adds a component equal to or lower than a horizontal boundary frequency with respect to the color signal to limit the band of the luminance signal in accordance with the motion, and a color subcarrier frequency from the color signal and the horizontal boundary. Taking out a component less than the difference from the frequency, taking out a component less than the difference between the color subcarrier frequency and the vertical boundary frequency from the component, and determining both components according to the amount of motion obtained by the selection means A second band-limiting unit that performs quadrature modulation with a chrominance subcarrier after mixing at a weighting ratio, and band-limits the color signal according to motion; and a luminance signal output from the first and second band-limiting units. And color signals with multiple frequencies To the second; and a second multiplexing means for generating a composite television signal.

(Operation) In the composite television signal generation circuit having the above configuration, in the case of (1), each of the motion amounts of the luminance signal and the chrominance signal is detected and the larger one is selected and output. The components equal to or greater than the horizontal boundary frequency are band-limited to the vertical boundary frequency or less according to the motion amount, and the color signals are color subcarrier frequencies and the horizontal boundary frequency according to the motion amount for the color signal. Or less, the band is limited to a component equal to or less than the difference between the color subcarrier frequency and the vertical boundary frequency, and then quadrature-modulated with the color subcarrier, and the color signal is frequency-multiplexed into the band-limited region of the luminance signal. To generate a composite television signal. According to this, since the composite television signal at the time of the moving image does not spread in the vertical direction with both the luminance signal and the chrominance signal, the composite television signal can be separated without causing crosstalk at a specific vertical frequency.

In the case of (2), the components of the luminance signal that are equal to or higher than the boundary frequency in the horizontal direction with respect to the additional signal and equal to or lower than the boundary frequencies in the vertical and time directions are band-limited, and the additional signal is frequency-multiplexed in the band-limited region. Detecting each motion amount of the multiplexed luminance signal and chrominance signal of the additional signal and selectively outputting the larger one, and extracting the component of the luminance signal equal to or higher than the horizontal boundary frequency with the chrominance signal, The band is limited to be equal to or less than the vertical boundary frequency in accordance with the amount, while the color signal is equal to or less than the difference between the color subcarrier frequency and the horizontal boundary frequency in accordance with the amount of motion, the color subcarrier frequency and the vertical direction. , And then quadrature-modulates with the color subcarrier, frequency-multiplexes the color signal into the band-limited region of the luminance signal to generate a composite television signal. According to this, a composite television signal at the time of a moving image is an additional signal,
Since neither the luminance signal nor the chrominance signal spreads in the vertical direction, separation can be performed at a specific vertical frequency without causing crosstalk.

In both (1) and (2), the vertical high-frequency component of the luminance signal is band-limited, but since the human visual characteristics are low in sensitivity to the resolution at the time of moving images, the image quality degradation at the time of moving images is almost negligible. .

(Embodiment) An embodiment of the present invention will be described below with reference to FIGS. 1 to 9.

FIG. 1 shows a configuration in which the present invention is applied to an NTSC encoder, and a luminance signal and a chrominance signal are adapted to the motion of an image to generate a composite television signal. However,
In FIG. 1, the same parts as those of the circuit of FIG. 10 are denoted by the same reference numerals, and the description thereof is omitted here.

First, R, C, and B video signals output from a signal source such as a camera and a VTR are converted into Y, I, and Q signals by a matrix circuit 11. Y signal is a low-pass filter (LPF) 3
6 and the subtractor 37. The cutoff frequency of the low-pass filter 36 is 3.0 [MHz], and the subtractor
The component of 3.0 [MHz] or higher is output from 37. This 3.0
Frequency signals above [MHz] are supplied to a vertical low-pass filter (vertical LPF) 38. The cutoff frequency of the vertical low-pass filter 38 is selected to be 525/8 [cph], and the output signal thereof is supplied to the first mixer circuit (MIX) 39 together with the output of the subtracter 37.

On the other hand, the Y signal output from the matrix circuit 11 is
At the same time, it is also supplied to the first motion detection circuit 40. This first
The motion detection circuit 40 calculates the difference component of the Y signal between one frame and generates a distant detection signal indicating the motion amount from the calculation result. The motion detection signal is a maximum value selection circuit (MA
A first mixer circuit 39 (and a second mixer circuit (MIX) 46 described later) via an X: 2 input which outputs the larger one) 41
Supplied to The mixer circuit 39 increases the weight of the output signal of the vertical low-pass filter 38 in accordance with the amount of motion when judging the motion detection signal as a moving image, and weights the output of the subtractor 37 when judging it as a still image. Is to be large. The output of the first mixer circuit 39 is a low-pass filter
It is supplied to the adder 42 together with the output of 36, where it is added and synthesized and supplied to the addition circuit (Σ) 12.

The I and Q signals output from the matrix circuit 11 are band-limited by the low-pass filters 13 and 14, and then time-division multiplexed by the selector 43. The IQ multiplexed signal output from the selector 43 is supplied to a second motion detection circuit 44, a low-pass filter (LPF) 45, a second mixer circuit 4
Supplied to 6. The second motion detection circuit 44 calculates the difference component between one frame from the I and Q multiplexed signals and generates a motion detection signal indicating the amount of motion from the calculation result. This motion detection signal selects the maximum value. The signal is supplied to the second mixer circuit 46 (and the above-described first mixer circuit 39) via the circuit 41. The maximum value selection circuit 41 compares the motion detection output of the Y signal and the motion detection output of the I / Q multiplexed signal and selects and outputs the maximum value. The output signal is a first and a second mixer circuit. It is used for controlling the mixing ratio in 39 and 46.

Only the low-frequency components of the I and Q multiplexed signals input to the low-pass filter 45 are extracted and further band-limited by a vertical low-pass filter (vertical LPEF) 47 before being supplied to a second mixer circuit 46. This second mixer circuit 46
As in the case of the Y signal, the weight of the I and Q multiplexed signals band-limited by the low-pass filter 45 and the vertical low-pass filter 47 is increased in the case of a moving image, and is output from the selector 43 in the case of a still image. The weighting of I and Q multiplexed signals which are not band-limited is increased and both are mixed and output.
The cutoff frequency of the low-pass filter 45 is 0.5 [MH
z], the cutoff frequency of the vertical low-pass filter 47 is 5
Selected as 25/8 [cph].

The I / Q multiplexed signal output from the second mixer circuit 46 is separated into an I signal and a Q signal by a separation circuit 48.
Then, the signals are balanced-modulated by the carrier signals (the frequency is fsc) from the carrier generation circuit 17 by the multipliers 15 and 16 and supplied to the addition circuit 12, where they are added to the Y signal to form a composite television signal. Derived as encoder output via 49.

2 and FIG. 3 show the spectra at the time of a moving image and a still image, respectively, and the operation thereof will be described below. Incidentally, in FIG. 2 and FIG.
(A) shows the frequency domain in the horizontal direction and the vertical direction, and (b) shows the frequency domain in the time direction and the vertical direction at the horizontal frequency a in (a).

First, the current Y is set by the low-pass filter 36 and the subtractor 37.
A horizontal component of 3.0 [MHz] or more is extracted from the signal, input to the first mixer circuit 39 for a still image, and is output from the output of the subtractor 37 by a vertical low-pass filter 38 to 525/8 [cp].
h] The following vertical component is extracted and the first
To the mixer circuit 39 of FIG. After performing the motion adaptive processing here, the adder 42 outputs 3.0 [MH from the low-pass filter 36.
z] and the following horizontal frequency components are input to the addition circuit 12.

On the other hand, the I / Q multiplexed signal output from the selector 43 is input to the second mixer circuit 46 for still images, and the I / Q multiplexed signal is
A horizontal component of [MHz] or less is extracted, and a vertical component of 525/8 [cph] or less is further extracted by a vertical low-pass filter 47 and input to the second mixer circuit 46 for a moving image. After performing the motion adaptation processing here, the separation circuit
At 48, the signals are separated into I and Q signals, quadrature-modulated by the carrier signals at the mixers 15 and 16, input to the addition circuit 12, and added to the Y signal to generate a composite television signal.

Here, if the image is a moving image, the mixing ratio of the first and second mixer circuits 39 and 46 changes according to the larger value of the amount of motion detected by the motion detecting circuits 40 and 44, respectively. Weight is applied to the components. For this reason, in the composite television signal, as shown in FIG. 2A, the luminance signal component of 3.0 [MHz] or more is band-limited to 525/8 [cph] or less, and the chrominance signal component is carrier frequency fsc = 3.58. The band is limited to ± 0.5 [MHz] in the horizontal direction and ± 525/8 [cph] in the vertical direction with respect to [MHz].

At this time, looking at the frequency domain of the composite television signal in the time direction and the vertical direction of 3.0 [MHz] or more, it spreads in the time direction as shown in FIG. 2 (b), but spreads in the vertical direction. 525/8 vertical frequency
Completely separated by [cph]. Therefore, even if the composite television signal obtained by this encoder is input to the conventional Y / C separation circuit shown in FIG. 11 and subjected to motion adaptive processing to perform Y / C separation, no crosstalk occurs. It is possible to separate the luminance signal and the color signal. In this case, although the oblique high frequency component of the luminance signal decreases, the visual angle of a human is insensitive to the movement, so that there is no apparent effect.

On the other hand, if the image is a still image, the first and second images are determined according to the larger value of the motion amount detected by the motion detection circuits 40 and 44, respectively.
The mixing ratio of the mixer circuits 39 and 46 changes, and the components for the still image are weighted. Therefore, in the composite television signal, as shown in FIG. 3A, the luminance signal component of 3.0 [MHz] or more is not band-limited, and the chrominance signal component is not band-limited either. At this time, looking at the frequency domain in the time direction and vertical direction of 3.0 [MHz] or more of the composite television signal,
As shown in FIG. 3 (b), although it spreads in the vertical direction, it does not spread in the time direction and is completely separated at a specific frequency in the time direction. Therefore, the conventional device shown in FIG.
The Y / C separation circuit can also separate the luminance signal and the chrominance signal without causing crosstalk.

Therefore, the NTSC encoder configured as described above generates a composite television signal by band-limiting the luminance signal and the chrominance signal so that the spectrum in the vertical direction does not spread during moving images. In addition, even when the signal is separated into color signals, crosstalk between the luminance signal and the color signal does not occur. Therefore, it is possible to perform Y / C separation that accurately adapts to motion without degrading image quality.

FIG. 4 shows another embodiment according to the present invention, in which this circuit is constructed so that an additional signal is multiplexed in the oblique high band of the luminance signal in the embodiment of FIG. In FIG. 4, the same parts as those in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted.

First, the Y signal output from the matrix circuit 11 is
It is input to the low-pass filter 50 and the subtractor 51. The low-pass filter 50 has a cut-off frequency selected to be 2.0 [MHz], extracts a low-frequency component of 2.0 [MHz] or less from the input Y signal, and supplies it to the subtractor 51 and the adder 52. Subtractor
The Y signal supplied to 51 is subjected to subtraction of low-frequency components of 2.0 [MHz] or lower, and is supplied to the vertical-time filter 53 as only high-frequency components of 2.0 [MHz] or higher. The vertical-time filter 53 limits the vertical component of the input signal to 525 × 3/8 [cph] or less and the time component to ± 15 [Hz] or less.
The output is combined by the adder 52 with the low-frequency component from the low-pass filter 50. By the above processing, the oblique high frequency component is reduced from the Y signal. The additional signal is multiplexed by the adder 54 in this area. The following is the same as in the case of FIG.

The specific configuration of the vertical-time filter 53 is shown in FIG. Here, a configuration with seven taps is shown as an example, but the number of taps can be increased by adding hardware.

The vertical-time filter shown in FIG. 5 converts the signal input to the input terminal 55 into one-line delay units (1H) 56 to 58 and 60 to 6
2 and a field memory (259H) 59, a predetermined pixel is taken out, and 0.1-1, -2, -262, -263,
7 lines of −264 and −265 are sent, and the second weighted sum circuit 6
To 4, seven line pixels of 0, −1, −2, −3, −263, −264, −265 are sent, and the calculation in the vertical direction is performed. The output of the first weighted sum circuit 63 is stored in the field memory (263H) 65.
, And is input to the selector 66 together with the output of the second weighted sum circuit 64. The selector 66 outputs the data from the output terminal 67 in the order of the first field and the second field.

That is, as shown in FIG. 6A, the first weighted sum circuit 63 calculates the weighted sum of the line pixels of -262 to -265 in the first field and the line pixels of 0 to -2 in the second field. Thus, the value of the -1 line pixel in the second field as the main tap is obtained. First weighted sum circuit
The output of 63 is the value of the second field as shown in FIG. 6B, and the value is delayed to the third field in the field memory 65 as shown in FIG. 6C.

On the other hand, in the second weighted sum circuit 64, as shown in FIG. 6 (d), the weighted sum of the -263 to -265 line pixels in the first field and the 0 to -2 line pixels in the second field is calculated. The value of −264 line pixels in the first field, which is the main tap, is obtained by calculation. Second weighted sum circuit 6
Since the output of 4 is the value of the second field as shown in FIG. 6 (e), if the output from the output terminal 67 in the order of the first field, the second field,... High frequency components can be reduced.

For example, as shown in FIG. 7A, when a black object moves in the horizontal direction on a white background, a luminance difference occurs between the first field and the second field, and a vertical high frequency component occurs. According to the vertical-temporal filter of FIG. 1, since the first field and the second field are operated simultaneously, FIG.
It is possible to reduce the vertical high frequency component as shown in.

FIG. 8 shows a spectrum at the time of a moving image and FIG. 9 shows a spectrum at the time of a still image in the embodiment of FIG. 8 and 9, (a) shows the frequency domain in the horizontal and vertical directions, and (b) shows the frequency domain in the time domain and the vertical domain at the horizontal frequency "a" in (a). Is shown.

As is evident from FIG. 8, in this encoder, the signals are multiplexed in the vertical high frequency range (3 × 525/8 to 525/2 [cph]) and the horizontal high frequency range (2.0 to 4.2 [MHz]). Since the additional signal is band-limited in the same manner as in the embodiment of FIG. 1, in the case of a moving image, it spreads in the time direction.
Luminance signal and chrominance signal are separated at 525 x 3/8 [cph], 525 x
Since the chrominance signal and the additional signal are separated at 3/8 [cph], the decoder can easily separate each signal with these threshold values. On the other hand, in the case of still images,
As shown in the figure, although it spreads in the vertical direction, the color signal and the luminance signal are separated at a specific frequency in the time direction, and the luminance signal and the additional signal are separated at a vertical frequency of 525/8 [cph]. The decoder can easily separate each signal using these threshold values.

Therefore, if the present invention is applied to an encoder that generates a composite television signal, it adapts to motion, and in the case of a moving image, the luminance signal has a component of 3.0 [MHz] or more at 525/8 [cp].
h] or less, and the color signal is horizontal 0.5 [MHz], vertical 525/8
Since it is limited to [cph] or less, complete Y / C separation can be performed without deteriorating the image quality at the decoder side. It is possible to separate the additional signal without causing crosstalk.

[Effects of the Invention] As described above, according to the present invention, Y / Y which accurately adapts to motion even at the time of moving images without deteriorating image quality
It is possible to provide a composite television signal generation circuit that can perform C separation and that can prevent crosstalk from occurring even when additional signals are multiplexed in an obliquely high band.

[Brief description of the drawings]

FIG. 1 is a block circuit diagram showing one embodiment of a composite television signal generation circuit according to the present invention, FIG. 2 is a diagram showing a composite television signal spectrum at the time of a moving image in the embodiment of FIG. 1, and FIG. FIG. 4 is a diagram showing a composite television signal spectrum at the time of a still picture in the embodiment of FIG. 1, FIG. 4 is a block circuit diagram in a case where an additional signal multiplexing function is added to the embodiment of FIG. 1, and FIG. FIG. 4 is a block circuit diagram showing a specific configuration of the vertical-time filter of the embodiment of FIG. 4, FIG. 6 is a diagram for explaining the operation of the vertical-time filter of FIG. 5, and FIG. 7 is FIG. FIG. 8 is a diagram showing a specific example of reducing the vertical high frequency component by the filter of FIG. 8, FIG. 8 is a diagram showing a composite television signal spectrum at the time of moving image of the embodiment of FIG. 4, and FIG. 9 is a diagram of the embodiment of FIG. FIG. 10 shows a composite television signal spectrum at the time of a still image, and FIG. Block circuit diagram showing the configuration of an encoder and a decoder in the NTSC system, Figure 11 is a block circuit diagram showing a configuration of a conventional motion adaptive Y / C separation circuit,
FIG. 12 is a diagram for explaining the operation principle of the circuit of FIG. 11,
FIG. 13 is a diagram for explaining a conventional means for multiplexing an additional signal on a composite television signal. 10 ... NTSC encoder, 11 ... Matrix circuit, 12 ...
... Addition circuits, 13,14 ... Low-pass filters, 15,16 ... Mixers, 17 ... Carrier generation circuits, 18 ... NTSC decoders,
19: Y / C separation circuit, 20: Inverse matrix circuit, 21, 22
… Mixer, 24, 25… Low-pass filter, 26… Composite television signal input terminal, 27… Subtractor, 28… Inter-line calculator, 29… Inter-frame calculator, 30… Motion detection , Gain control circuit, 33 horizontal bandpass filter, 34 color signal output terminal, 35 luminance signal output terminal
36 low-pass filter, 37 subtractor, 38 low-pass filter in the vertical direction, 39 first mixer circuit, 40
Motion detection circuit, 41 ... Maximum value selection circuit, 42 ... Adder,
43 selector 44 motion detector circuit 45 low-pass filter 47 vertical low-pass filter 46 second mixer circuit 48 I / Q separation circuit 49 composite television Signal output terminal, 50 ... Low-pass filter, 51 ...
... subtractor, 52 ... adder, 53 ... vertical-time filter,
54 ... Adder, 56-58, 60-62 ... 1-line delay device, 59
…… Field memory, 63,64 …… Weighted sum circuit, 65 ……
Field memory, 66 ... selector, 67 ... additional signal multiplex output terminal.

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Noriya Sakamoto, Inventor No. 8 Shinsugita-cho, Isogo-ku, Yokohama-shi, Kanagawa Pref. ) JP-A-63-90990 (JP, A)

Claims (2)

(57) [Claims] 1. A composite television signal generating circuit for multiplexing a luminance signal and a chrominance signal to generate a composite television signal, wherein a motion detecting means for detecting each motion amount of the luminance signal and the chrominance signal; Selecting means for selecting and outputting the larger one of the motion amounts of the luminance signal and the chrominance signal obtained in the step, extracting a component equal to or higher than a horizontal boundary frequency with the chrominance signal from the luminance signal, and The components below the vertical boundary frequency are extracted, and both components are mixed at a weighting ratio determined according to the amount of motion obtained by the selecting means. The mixed output is added to the horizontal boundary frequency with the color signal. A first band limiting unit that adds the following components to limit the luminance signal in accordance with the motion, and extracts a component equal to or less than a difference between a color subcarrier frequency and the horizontal boundary frequency from the chrominance signal, Ingredient After taking out a component equal to or less than the difference between the color subcarrier frequency and the vertical boundary frequency, mixing this component with the current color signal at a weighting ratio determined according to the amount of motion obtained by the selection means, A second band-limiting unit that performs quadrature modulation on the sub-carrier and band-limits the chrominance signal according to the motion, and frequency-multiplexes the luminance signal and the chrominance signal output from the first and second band-limiting units. Multiplexing means for generating a composite television signal. 2. A composite television signal generating circuit for multiplexing a luminance signal, a chrominance signal and an additional signal to generate a composite television signal, wherein a component equal to or higher than a horizontal boundary frequency with the additional signal is extracted from the luminance signal. A third component for extracting a component equal to or less than a boundary frequency in a vertical direction and a time direction with respect to an additional signal from the component, and adding the component and a component equal to or less than a boundary frequency in a horizontal direction with the additional signal to band-limit a luminance signal. Band limiting means, first multiplexing means for frequency-multiplexing an additional signal in a frequency-limited frequency region of the luminance signal obtained by this means, and each motion amount of the luminance signal and the chrominance signal obtained by this means A motion detection means for detecting the color difference, a selection means for selectively outputting the larger of the motion amounts of the luminance signal and the color signal obtained by this means, and a color from the luminance signal obtained by the first multiplexing means. A component equal to or higher than the horizontal boundary frequency with respect to the signal is extracted, and a component equal to or lower than the vertical boundary frequency with the color signal is extracted from the component, and both components are determined according to the amount of motion obtained by the selection means. First band limiting means for mixing at a weighting ratio, adding a component equal to or lower than the horizontal boundary frequency with the color signal to the mixed output, and band limiting the luminance signal in accordance with the motion; A component that is equal to or less than the difference between the subcarrier frequency and the horizontal boundary frequency is extracted, and a component that is equal to or less than the difference between the color subcarrier frequency and the vertical boundary frequency is extracted from the component, and both components are obtained by the selection unit. A second band limiting unit that performs quadrature modulation with a color subcarrier after mixing at a weighting ratio determined according to the determined amount of motion, and band-limits a color signal according to the motion; and the first and second band limiting units. Output from the band limiting means Composite television signal generating circuit, characterized by comprising a second multiplexing means for generating a composite television signal by frequency-multiplexing a luminance signal and color signals.