JPS5923984A - Luminance signal/chrominance signal separating circuit - Google Patents

Abstract

PURPOSE:To make switching between NTSC and PAL by the output of an FSC filter and its doubled output, by installing an 1-H delay circuit, a comb line filter whose gain is ''0'' at a frequency nfH, ''1'' at (n+1/2)fH, and ''0.5'' at (n+ or - 1/4)fH, and the FSC filter, whose signal is ''1'' at a frequency fSC. CONSTITUTION:A comb line filter 401 which inputs digital video signas 110 and a filter 412 having a BPF characteristic, in which the gain is ''1'' at a frequency fSC, are cascade-connected. The filter 401 consists of a 2-H delay circuit 126 composed of 1-H delay circuits 402 and 403, coefficient multipliers 407-409 for each coefficient 1/4, 1/2, and 1/4, respectively, and an adder 410. YC separation is performed by the coefficient multipliers and the fSC filter 412. An NTSC/PAL switching circuit 420 outputs an C-signal as it is under the NTSC mode and after the C-signal is shifted by one bit to the MSB side and the value is doubled under the PAL mode, in accordance with the ''0'' and ''1'' of a change-over signal 146. Therefore, a YC separating circuit wich can correspond to both correspond to both systems of NTSC and PAL can be formed with a simple constitution.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a digital television receiver that digitally performs base/base video (i) processing, particularly n IJI: fu and chromaticity. This invention relates to a circuit that separates No. 1 (hereinafter referred to as a Y/C separation circuit).

[Technical background of the invention and ranking points]

Since then, all signal processing in television receivers has been carried out by analog 1-channel processing C2, but in particular, the following improvements have been made to the analog signal processing of 1-photo signals from the 1st video stage onwards. There was a problem. In other words, performance C2 is a problem caused by processing performance C2 on the time axis, which is considered to be a general weakness of analog signal processing.Specifically, it is a problem caused by the processing performance C2 on the time axis, which is a general weakness of analog signal processing. These include chromaticity signal separation performance, various image quality improvement performance, and synchronization performance. On the other hand, the problem in terms of cost and production is that even if the circuit is made into an IC, there are still many external parts and adjustments.

In order to solve this problem, the color 4m after the video stage is
Coding and demodulation (2) It is possible to fully digitalize signal processing.
It has been f.

By the way, there are many color television systems including NTSC, FAT, etc., but NTSC, I'
Since both types have a lot in common, it is industrially desirable to be able to use them in common with a simple switching operation f2 for television receivers. One of the differences between the NTSC and PAL systems is the frequency distribution of the luminance signal and chromaticity signal, so the Y/C separation circuit for separating these signals from the video signal is also compatible with both systems. Must.

Conventional analog signal processing C double-sided television reception 74
% (7) In the case of N-type (2), Y/'C HWig circuits corresponding to both NTSC and PAL systems are prepared separately, and there is a metal base that should be improved here.
Although it is considered advantageous to be able to make the C separation circuit into both types (two pairs) with a simple switching operation, it is quite difficult in analog signal processing, and even if it were possible to do so, it would be rather costly. The ability to become tjJ is I('h.

[Purpose of the invention]

1-1 of the present invention, by taking advantage of the features of a digital television receiver that performs 1214M processing from digital signal processing C2, C1 opening switching operation (from NTS C
To provide a Y/C separation circuit that is compatible with both P A and L types and can be realized with simple hardware.
That's true.

[Summary of the invention]

In the Y/C separation circuit according to the present invention (2), the luminance signal and two chromaticity signals in the NT8C signal each have a frequency i=n10.
(n + >) Localized near fH, the luminance 4i in PAL 1 and 2 chromaticity signals in No. 4 are /=n/at(
n±+) fl2 localized point C, NTSC with a simple C11 digital circuit configuration.

It is designed to be compatible with both PAL formats.

In other words, the period of the horizontal frequency afn at C2 on the frequency axis is 1υ
A comb filter with 1 (2 and its circumference l skin number characteristic (force) is, for example, A (force = = old (1 - co l (2ff7/ f H
) ) is given by A (r+f, a) = Q
.

Enter ((n+T)fH)=l, A ((n+)/
)l ) = 0.5, so for NT and 9C signals, A
(Color jW times signal separated using force itself tt1PAL
In the signal, by multiplying the filter output by 2 times the characteristic of AU), the chromaticity value becomes equal to ν.

Therefore, in the present invention, a 10 ml comb-shaped filter is used, which sequentially outputs a plurality of delayed signals shifted by one horizontal period r.
The delay circuit includes a delay circuit that outputs a plurality of delayed signals (two-pair j-so-determined calculations and outputs the calculation results at a frequency of 1=nip and a gain of 0.
f=(n+1) fH and dyne is 11 i= (n±t)
A comb or filter with a frequency characteristic of fH''c dyne of 05 and f-jsc (jSC is the color subcarrier frequency)
NTSC/P
When in NTSC mode due to the AL switching circuit,
When in PAL mode, 1st shift is doubled (double) and output as color 1 casualty signal output.

On the other hand, in the case of the luminance signal C, the separated chromaticity signal and any one delay signal (video signal) of the delay circuit of the comb filter are combined as described above. The chromaticity signal component and the chromaticity signal are subtracted by matching the delay time of the chromaticity signal (separated by two).

〔Effect of the invention〕

According to the present invention (2), the filter part for chromaticity signal separation, which occupies most of the hardware of the Y/C separation circuit, can be shared between NTSC and PAL. The process of doubling is
For digital signals, only a 1-bit bit shift to the MSB side is required by the I operation (-), and it is also possible to switch the delay time of the delay circuit in the two-comb filter C2 when switching between NTSC and PAL modes. This can be achieved with a simple dart.

Therefore, the Y/C separation circuit for NTSC can be used for PAL by adding only a few circuits, and the industrial effect is extremely large.

In addition, the characteristics of the comb filter can be realized by 3-line correlation calculation, and in terms of performance, the 2-line correlation (
Compared to the horizontal filter f2, it has poor resolution performance in the vertical direction.

This is comparable in performance to the comb filter used in conventional PAL television receivers, and therefore N
Considering that it is compatible with both TSC and PALfflli systems, improvements in performance as a whole have been achieved at the same time.

Embodiments of the Invention] FIG. 1 shows an overall block diagram of an image processing circuit 1100 that demodulates digital signal processing (two-way RGB (No. 6) from a baseband single log video signal. In Figure 2, the 16th line indicated by a thin arrow represents an analog signal or a 1-bit digital signal line, and the signal line indicated by a thick arrow represents a digital M number line quantized with multiple bits. In addition, the digital television receiver explained as an example is
It is possible to demodulate both NTSC and PAL signals, and this switching must be done manually. Hereinafter, the outline of the image processing circuit 1υO will be explained using No. 1121, and the details of the main parts will be explained next (C2).

(+1 A/D conversion, Flang system, P L LM circuit.

The analog video signal lθ input to the synchronization/timing image processing circuit IIjti is passed through a buffer 102 to a low-pass filter (hereinafter referred to as LPF). There are two of us. LP
FJ 03 is a ^/D converter (hereinafter referred to as DC).
) It serves to remove high-frequency noise that causes aliasing distortion during numbering performed at 109.

The output of the LPF I OJ is inputted to the adder 105C via the buffer 104, and added to the flag signal 106, and then sent to the ADCJ (
79. The ADC'109 performs sampling and digitization of the input signal. Note that the amplifier 1'OII uses the output signal 10 of the adder 105 in order to effectively utilize the dynamic range of the ADCJ (19).
7 is output to ADCZ 09 with the amplitude gIM node.

Here, kDcI 09→Clang times j烙112→D/
A converter (hereinafter referred to as DAC) 114 → adder 1
A control loop is formed by 05 → amplifier 108 → ADC 109, and this control loop outputs digital video from C2 to A'DC70g. In this control loop, the clamp circuit 112 has 1) C1
A digital video signal 110, which is the output of 09, and a signal 11 from a synchronization separation/timing generation circuit 122, which will be described later, are input. This clamp circuit 112 first calculates the average value (idesteral level) of the burst portion of the digital video signal 110. Next, the difference between the calculated 1e death level and the u' page is expressed as 1. and output as a false flower signal 113. The error signal 113 is converted into an analog clamp signal 106 by the D input C114, and then subjected to the above-mentioned p addition N'e'4z
At o s, the output signal of the buffer 104 is added to the sweetness by 1. As a result, the DC component of the video signal 107 output from the Ugai 6xos changes, and a system is implemented to bring the pedestal level of this signal 107 closer to the target value. Then, when this signal 107 is activated, the amplifier 108 for directing the hatchet, and the input DCI 09
The digital video signal 1101'' is then converted and seven times later, the flag circuit 112 (two-person error 11 and 113) is calculated again. Ideal clamping is performed by the above operation.

On the other hand, sampling is performed at the timing of sampling/4' pulse 116 (φS) output from the mechanically suppressed crystal oscillator (hereinafter referred to as VCXO) 115.

In this embodiment, the frequency fs of the sampling pulse 116 (φS) is set to fm=47'sc. (fsC
is the color subcarrier frequency: in NTSC, fmc =
3.58 MH1PAL f*c=4.43Mk1
g), NTSC.

For both PAL signals, the hue component of the color signal is subjected to a color sub-gear riff (2-phase change IM), so the relative phase of the sample rig pulse 1I6 (φs) and the sword 2-burst is the color signal. Determine the demodulation axis when demodulating and determine the hue.For this reason, the
The 16(φg)'7) position/eye needs to be locked to the phase of Kara~/T-St. This control is
C109 → Phase detection [Circuit 118 → D input C120-+V
CXOI 15・→Enter DCI 09 Nobunari P L
L loop (performed by two. The song is as follows.

First, the digital video signal 110 and the burst sampling signal 11] are input to the phase detection circuit 117. In this phase detection circuit 117, the color burst portion of the digital video signal 77 (7) is extracted by the burst sampling nozzle III, and the actual tingle position in this color burst portion is compared with the phase target value 117 (θ0). Difference (θ
−θ. ) is calculated and output as the phase ml difference Ig 119. However, in reality, as will be described later, the phase error signal 119 has a magnitude proportional to sin (θ-θ.). The phase error signal 119 is converted into an analog signal C by a DACZJ□, and VCXOzz5 is applied as a VCXO control pressure 121. By KooL, vC
Sampling Yarus 116 (which is the output of XO115)
The phase of φB) is controlled so as to approach the phase target value 117 (θo)−2.

Note that hue control is performed by changing the phase target value 117 (θ.) f2.

(Details of the PLL circuit will be described later.) Also, the sampling pulse 116 (φm)) t, and (the dihedral image processing circuit 1
Each block C2 is supplied as an operating reference for the digital circuit section in 00.

The synchronization separation/timing generation circuit 122 receives the digital video signal 110 and outputs a burst sampling pulse 111 and a horizontal/vertical synchronization signal 123 through a predetermined operation C2. Burst extraction/Rusuno 77 j;t, previous Suno G flang circuit 112 and position 471 detection circuit 11
The horizontal and vertical synchronizing signals 12.7 are input to the countdown circuit 124. Countdown circuit 1
24, by counting down the sampling pulse ll6 (φS), horizontal/vertical synchronization/self 125
is made. The horizontal and vertical synchronization pulses 12 operate the CRT via a synchronization drive apposition.

The digital video signal 110 has its sample phase, pedestal level, and amplitude adjusted by C2 as described above, and is then provided to the RGB demodulation/image quality control system (2) described below.

+2) RGB demodulation/image quality control thread 2TH delay times @
126 converts the digital video signal 11θ to OTHF1'I
A signal 127 delayed by a time HP2TH (TH: 1 horizontal time) is output. This delayed signal 127 is required for each performance using the line correlation that will be performed below.

Note that the sampling frequency fs = 47sc
Therefore, fs=910/y+ in NTSC.

In PAL, /s=1135 fH, and the number of delay stages required for ITH is 910.1135 bits each. (fH: horizontal frequency = 1/TH).

・The 4th extension signal 127 is the #jy signal/chromaticity signal separation circuit (
(hereinafter referred to as a Y/C circuit) 128 and a Y signal processing circuit 129.

The Y/C separation circuit 128 has 4 OTH, ITHr2TH
Calculation using extended signal 127 (line correlation calculation) A comb filter realized from C2 and a gain of 1 with f-4=C.
A band-pass filter (hereinafter referred to as BPF) is used to separate the chromaticity Iba signal (hereinafter referred to as C signal) , and 13 luminance signals (hereinafter referred to as Y signals) are separated. (Details will be described later) The Y signal processing circuit 129 inputs the delayed signal 127, the YGt No. 13, and the mobilization control signal 132 from the outside, and performs each correction of the Y signal 131C - horizontal contour, vertical contour, contrast, and brightness. After alms zy', anew Y
Signal I J,? Output as . In addition, at the time of the contrast supplementary market, there will be a fly pack! Lus 134 is used. (Details will be described later) The C signal 130 is input to a color control/color killer circuit 135. The color control/color killer circuit 135 detects the burst amplitude of the C signal 130 and performs color control and color killer operations based on this trick. Color killer signal 137 obtained from this color control/color killer circuit 135
is also input to the Y/C separation circuit 128, which performs control so that the video signal is output as is as the Y signal 131 in order to widen the band of the Y signal 131 during color killer operation.

In the color control/color killer circuit 135, the width (color saturation) of the C signal iso is also adjusted by the color control IR number 136C2 from the outside.

(Detailed publication 1 is later non-1)) The C signal 138 output from the color control/color killer circuit 7.7.5 enters the color demodulation circuit at I J 9.
The signal is synchronously demodulated by the color demodulation sub-control pulse 140 from the phase detection circuit 118. Normally, the sampling phase NTSC't'' in AI) CI 09 is set to the I and Q axes, and to the U and V axes C in PAL, so the demodulated glrl C signal 141 obtained by the color demodulation circuit 139 is 2, respectively.

9 numbers and U and V signals. (Details will be described later) Y signal 1
33 and the demodulated C signal 141 are manually input to the matrix circuit 142, multiplied by a predetermined demodulation coefficient, and then added.
It is converted into a GB signal 143. This RGB signal 143 is converted into an analog signal 145 by I) ACJ44. This signal 145 is input to the CRT via the RGB output circuit.

Note that switching between P input and NTSC is performed by inputting the NT8C/PAL switching signal 146 to a predetermined circuit.

Next, C2, the characteristic circuit C in the image processing circuit 100 shown in FIG. 1 will be explained in detail.

(PLL circuit) FIG. 2 shows a PLL circuit 2θ including a phase detection circuit 118.
FIG. 2 is a diagram showing a more specific configuration of O.

The function of the circuit 200 is to lock the phase of the chimbling pulse 1115 (φS) to the burst phase (-) and to perform the hue sub-part by setting the phase target value 117 in degrees. 52, the phase detection circuit IJ8 (
The input digital video signal 110 is darted by the burst sampling pulse 111 and the color burst 2
02 is extracted. Color Perspective) J02 has a phase error calculation circuit 203C that requires two people. A specific example of phase error calculation is described in, for example, US Pat. No. 4,291,332 C2. FIG. 3 is a diagram for explaining this phase error calculation, and shows sample points P, .
P,...P, k are shown. ! Color burst 2o2 in FIG. 82 can be considered as a data string from 1'1 to P4.

P and -P4 are values obtained by sampling a point shifted by θ with respect to the burst phase C2 every 90 degrees. Therefore, it can be expressed as follows.

P4n-3==a-4-bsinθ P4n-t=a+bsin (θ+906)P,
, 11 = a + b sin (θ+180°)P<
n = n −4−b sia (θ+270°)
(n=1~k) Target sample phase is θ. Then, the following formula holds true.

n'=I
n = 1 The right side of equation (1) is a function of (θ-00) and can be considered as the phase error signal 204. (13
The left side of the equation is the operation 'S for determining the phase error signal 204.
It shows. In other words, if the data sequence P1#P2#...P, kC of the color burst 202 is performed as shown in the left side of equation (1), the phase error signal 2 on the right side of equation (])
θ4 will be output.

In addition, on the left side of equation (1), the target sampling phase θ
Since the information of 0 is entered in the form of tanθ0, in this embodiment, the phase target 4tHxy contains θ. Instead, the value -00 is used directly. In the case of NTSC, the ■ axis is the reference phase of the sample (: then θ.--57", and the phase lTI target value 117 is 10, =-1.54. In the case of PAL, the burst phase is Since it varies from 180° to 45° for each line, for example, if the -U axis (180°) is the reference phase of the sample, θ0 = ±45°. Therefore,
The phase target value 117 also needs to be switched by -00-±1 for each line. This switching is basically performed by determining whether the duplex phase of the inputted colorist 202 is +45° or -45°. This switching 1
The R signal is output as a PAL amplifier signal 205. The PAL identification signal 205 is: ■The signal is +90'
There is a signal C indicating whether the color signal is modulated by -906 or -906, and C2 is required when adjusting the color signal.

Therefore, the PAL identification signal 205 is outputted to the color demodulation circuit 139 as a color demodulation control 1/# pulse 140 together with a reference phase pulse 206 indicating the reference phase of the sample (in this embodiment, The I-axis is used for NTSC and the U-axis is used for PAL as the In position of the camera.) The phase error signal 204 created by the calculation shown on the left side of equation (1) is I; P F 207 C is input.

The PF 207 determines the time constant of the PLL operation, and its constant is normally set to about 10TH. The output 119 of LPFJ 07 is l) A CI
The VCXO 115CCX is used through the VCXO 115 and controls the sampling pulse II6 (φ). In addition, the VCXOII5 has an oscillation frequency of 143 MHz (N T 8 C
) and 17.7MHz (I'AL).

Next, the operation of controlling the hue using the phase target value 117C2 will be described. As mentioned above (2. In this embodiment, when the target sample phase with the burst phase as the standard is 00, the phase target value II7 is given as 100. Therefore, instead of the meeting ηθ0, τ21葡( If you input θ.10,), the demodulation axis will change by 01, and the hue will change by the same phase in the same direction for all colors C. Also, the performance Δ for hue control using this method is specifically Specifically (1
) is shown by the second term on the left side of the equation. In fact, the value calculated from color burst 202 is 117! This is done by calculation. Therefore, the circuit added for hue control only needs to be a multiplication circuit. Note that the method of changing the hue by changing the demodulation axis is the same as the method used in current analog color televisions.

The following two methods can be considered as other methods of controlling hue. One is the mutual dyne'% of HifJ C4:7 No. 141 (I and Ql or U and V)! The other method is to change the demodulation coefficient tr in the matrix circuit 142C.
) increases and the hue becomes intermediate (amount and direction of change).
Since the hue is different from the two, the control is complicated and has the disadvantage of being complicated.For the latter two, the demodulation coefficients related to the color in the matrix circuits 1 and 2 are NTSC.

Since there are six PALs, the increase in hardware and the complexity of control are even greater than in the former. Therefore, for the two hue controls, the method for changing the color tone in digital television receivers is as follows:
It is most suitable and vivid in terms of added hardness and ease of control.

(In the Y/C separation circuit R1 in Figure 1-, the separation of the C signal 130 and Y signal 131 from the digital video signal 110 is 2T) ()j@
This is performed by a spreading circuit 126 and a Y/C separation circuit 128, and these two circuits constitute a Y/C separation filter.

Figure 4 112 T FIz! % court circuit 126 and Y/
4 is a diagram illustrating a specific configuration example of a C-portion 4 circuit 128. FIG.

First, the procedure for separating the r digital video signal IIθ from the C signal 130 and the Y signal J+131 will be described using FIG.

That is, a comb filter 401 having fHO periodicity and having a gain of zero at f=, n f yr, and a C signal band filter 412 having a BPF characteristic with a gain of l at f=fsc are connected in an R-connection. From C2, ITH slow grinding signal 405
4 extracts the C signal 419 included in . C signal 41
9 is the NT8C/PAL switching time (t4 (2 o y) and is then output as a new C signal 130. Also, this C signal 130 passes through the C signal dart 421 and is input to the subtracter 425L. On the other hand, the comb filter The ITu delay signal 408, which is the phase center of the signal 401, has a phase (
Two subtracters 425L are passed through an adjustment delay circuit 423 for including delay agitation. and decrease) I device 425 (second, key! 1. Video signal 424 of the output of the slow grinding circuit 423
By calculating 1 the C signal 422 that has passed through r-t 421'lf, No. 714 131 is divided by 1 and output.

Next (2. Dark blue) The circuit shown in Figure 4 will be explained in more detail.

2TFr delay circuit 121; is I T J (4 delay circuit 40
This is a configuration in which 2°403 are connected in cascade. ITH continuous lc
Each of the l paths 402 and 401 is delayed from the NTSC'/PAL switching signal 146C2), 4 is delayed from 9101'' and 5 (NT
SC) (!:l 135TS (PAL). Here, TfI is the sampling period: Ts=l/fa
=1/4 fsc. The delay signal 127 output from the 2TH delay circuit 126 is 0T) (delay signal (4 odd) 404, lTH slow grinding number '405.2 T 1r
;Li j'lj, signal 406, which are Y/
The signal is input to the C separation circuit 128.

In the Y/C separation circuit 128, first, a comb-shaped frequency characteristic layer
A third performance will be held to accompany the event. This is the input OT
tr # I T II # 2 T)! Delayed signal 4
04°405.406 each (two coefficients -+, i, -
After multiplying by f-, these are added by the addition 1 circuit 410. The coefficient used here - 10, L is a number that is a power of 2, so the coefficient next month is 407°408.40
9 actually requires only wiring operations, and in the case of a negative coefficient, only an inverter is added. I of the comb filter 401
! The R wave number characteristic Hcomb (1) is -TFI/Ts +TH/TsHeomb(force=-+Z +,!--+Z=CH(1-CO
8(2πf/fH))・・・・・・・・・・・・(2)
(Z = e″″j・2πfT s >.

@Heomb(n/1)=0°Hcom given by
From the characteristic C2 of b((n+-1)fHJ=i, C signal 41
1 is separated. The C signal bandpass filter 412 is
Delay circuits 413, 414, coefficient multipliers 415, 41f;
, 417, added $'a4111C. It is composed of a coefficient multiplier 418. Coefficient multiplier 4115, 416, 4
17, as described above, can be realized only by wiring operations or in-house installation. FtJ of C48 bandpass filter 412
/f1 number characteristic HBPF (1) is HRPF (force=-ΣZ + 1-, -Z=: l
-COS (π7/2/SC) ・・・・・・・・・
... is given by (3). The C signal bandpass filter 412 used here is characterized by being realized with simple hardware, and its frequency characteristics also have a simple form as shown in equation (3). Moreover, since this filter 412 is used in combination with the comb filter 401, the overall Y
Despite the simple hardware configuration, a practically satisfactory performance can be obtained. The output of the C signal band filter 412 is the NTSC/PAL switching circuit 420C.
The two of us are strong.

The NTS C/PmL switching circuit 420 is NTf9C/
From the content C2 of the PAI and switching signal 146, this is the NTS
In the case of C mode, the C signal 419 is output as is, and the P
The implication of the AL mode is to double the amplitude of the C signal 419 and output it. This is due to the following reason (-).

Cylindrical filter 4100 frequency characteristics) 1comb (71 is given by equation (2) regardless of NTSC, PAL+=
Hcomb (n fH) = 0.

]-1comb((n±-)) f )! )=0.5
, Hcomb ((n+4)fH)=1. N
TSC signal (7) jiM 6, Y signal is f=nfH,
The C signal is near t = (n+') fu.
Since the signal is localized, the C signal can be obtained directly by using the frequency characteristic of equation (2).

Figure 5(a) shows the Yfri spectrum of the NTSC signal (
dotted arrow l:I]), C signal spectrum (solid arrow),
Hcomb (This is a diagram showing the relationship between forces. On the other hand, in the case of a PAL signal, the Y signal is f=nfH, the U signal of the C signal is f=(n-+)fH, and V4 is 1f=(n+). −))
C is localized near fH. Therefore, if we use the frequency characteristic shown in equation (2) as is to separate the C signal (U signal and V signal), the gain at the C signal Cf = (n-b- to -) fH) will be halved. becomes. Therefore, in the case of a PAL signal, if the dyne of Hc omb(f) is doubled,
The correct C signal will be separated. Figure 5(b) shows the Y signal spectrum (dotted line arrow), U signal spectrum (solid line arrow), ■ signal spectrum (dotted chain arrow), and 2·l(comb) force relationship of the PAL signal. FIG.

In Fig. 5(b), the gain is 2 at f = (n + ±) fH.
However, this is not a problem in practice because the target is the high-frequency component C in the vertical direction of the C signal. On the other hand, the C signal band filter 412 actually has a frequency characteristic of HBFF (
Since the power has a BPF characteristic in which the gain is 1 at f==fsc in both cases of N'l'SC and PAL, as shown in equation (3), it can be shared as is with NTSC and PAL. Comb filter 401 and C signal band filter 412 can be considered together, and in the case of NT8C signal, Hcomb (
7')・1(RPF(force), and in the case of a P A 1. signal, it is sufficient to separate No. 016 using 2Hcomb(n4(RPF(1)).

The specific configuration of the NTS C7P A LF4JJ circuit 420 is, for example, as shown in FIG. 146 is 61" in PAL mode, 1 in NT8C mode
It shall be '0'. r-in switching circuit 50], the C signal 419 is selected in the NTSC mode by a predetermined dart configuration.
output as is, and output 1-AC signal 41 with "PkL mode)"
By shifting 1 bit to the 9kM8B side, the value is doubled and output. The overflow/underplow prevention circuit IN4602 inputs the output signal of the dyne switching circuit 601, and when this is 2° (=1) or more.

If it is -2 or less, it will be 2-21 Nikuramp. The reason this circuit is necessary is that Hcomb (
f) -HBpr There are places where (1) exceeds dyne 1 within the video band, and in the case of special C2 PAL mode,
Therefore, depending on the pattern C2, there is a possibility that the output signal of the dyne switching circuit 601 exceeds the range of -2 to (2-2), which is the dynamic range of signal processing. Without the underflow prevention circuit 602, a signal of 2 degrees or more would be treated as negative, and -
Signals smaller than 2° are treated as positive. Overflow/underflow prevention circuit t; o In 2, 2 bits 60 of the input signal are
3.2 bits 604 are detected, each being 0", '1"
When , it is regarded as an overflow and 2° 2-t is output. Also, 2 bits 603 and 2 bits 604 are each 1
1″.

When it is ``O'', it is regarded as an underflow and -2 is output.

The advantage of switching between NTSC and PAL using the method described above is that the added circuit is NTSC/PAL.
Only the A/L switching circuit 420 is required, which is only 40~
This is achieved with 50 gates.

In FIG. 4, the C signal 130 output from the NTSC/P input switching circuit 420 is output to the color control/color killer circuit 135, and the CIH number 421C2 is also input. When the color killer signal 137 is inputted from the color control/color killer circuits 13 and 5, this port 421 closes C when the color killer is in operation and makes the C signal output 422 to the reduction IF and device 425 zero. . Therefore, in this case, the Y signal 131
, the video signal 424 appears as it is (2). Normal color killer operation is to just set C48 No. 130 to zero (2), but on Kino's side, - the above-mentioned operation (2 makes the color killer Y / It also acts on the C separation circuit 128.For this reason, during color killer operation, YM
No. 131 has the advantage of eliminating the band limit and increasing the band.

To summarize the above explanation regarding Y signal separation, the Y signal separation characteristic HY from the video signal 424 to the Y signal 131 is as follows.
can be expressed as . This Y signal 131 is output to the Y signal processing circuit 129.

(Y, No. 1g' processing circuit) The function of the Y signal processing circuit 129 is to perform corrections on the Y signal 131 (bilateral contour, vertical contour, contrast, and brightness) and output it to the matrix circuit 142.

FIG. 7 shows a specific example of the configuration of the Y signal processing circuit 129. The Y signal processing circuit 129 includes a vertical contour circuit 701 and a water/F
@91< It is composed of a circuit 702, a contrast circuit 703, a coupling circuit 711, and a pedestal clamp circuit 713. Further, the image quality control signal 132 is a vertical contour control signal 704, a horizontal contour=r control signal 7
05, a contrast control signal 706, and a brightness control signal 707. 2T) T slow fly circuit 12
The slow MHit No. 127 output from 6 has vertical and horizontal wheels!
1 (and each contrast circuit 701゜702.703
The vertical/horizontal contour and contrast signals 70g and 109.710 are output. The dynes of these signals are adjusted by vertical and horizontal contour and contrast control signals 704, 705, and 706. In KDryii, permanent/water/1i contour and contrast signals 7011, 709, 710 and Y signal 13)
and a bright control signal 707 from the outside are added together. Bright control is to adjust the DC component of the Y signal 131 using the bright control signal 707 (2), and this is performed by the adder FIX and the pedestal clamp circuit 713. , horizontal contour, contrast, and brightness, it is output as a new C Y signal Z 3 , ? and enters the matrix circuit 144. Each circuit in the Y signal processing circuit 129 will be explained in detail below. .

(1) Vertical contour circuit A concrete example of the vertical contour circuit 701 shown in FIG.
, the vertical contour signal 70B is generated by the 2TR delay circuit 126 and the vertical contour circuit 'I'fr 701. This can be considered as a continuous connection of the vertical HPF 801 and LPF 807 having a comb filter configuration. Vertical HPF8
01 is a filter that passes components that vary greatly in the vertical direction on the screen J2, and its output signal 806I- includes a vertical contour component. Here, vertical HPJ "801" and vertical frequency (there are two and will be briefly explained. Vertical I■1"
'F801 is actually exactly the same as the comb filter 401 for separating the C signal 41) in FIG. 4, and is actually used in common with this filter, but is treated separately for ease of explanation. That is, coefficient multipliers 802 to 8 (11 and D
o The JV unit sos is the coefficient multiplier 407 in FIG.
˜409 and the adder 410. The reason why these two have the same shape is that the C signal also has high frequency components in the vertical direction. Vertical frequency represents the repetition of the screen in the vertical direction, and is expressed in units of cycles.
/picture bright is used. (hereinafter c
6) Figure 10 shows the vertical frequency F(
cy./ph.) and JIV+frequently used frequency f(HE)C, hereinafter referred to as horizontal frequency. )
It is a figure which shows typically the relationship between and a pattern. The vertical frequency corresponds to the change in the vertical direction of the picture (2), and the horizontal frequency corresponds to the change in the horizontal direction of the picture (C).The horizontal frequency f and the vertical frequency F are collectively expressed as is often called a two-dimensional frequency, and Figure 11 is similar to Figure 10 (a
), (bl.

The frequency components corresponding to each picture shown in (C) are expressed in a two-dimensional frequency format. FIG. 12 is a diagram representing a television signal in a two-dimensional frequency format. The scale is written on a standardized frequency scale11 so that it can be expressed commonly in NTSC and PAL. The horizontal frequency is the number of cycles d normalized by the sampling frequency fs (=4fsc), and the vertical frequency is the number of scanning lines per field f1 (//V(
fv is the field frequency). Also, generally the frequency is fcHz)=Cn+a)f
Vertical frequency F(cy・/P−h
, ) depends on H P =---m and 7. (n=natural ff, l>!>0
°fv fv: field frequency). For example, the vertical frequency of the color subcarrier is 625 x s in NTSC.
=234.375 (cy·/ph·).

On the other hand, the horizontal frequency of the color subcarrier is NTSC and I
'AL, but the normalized frequency representation is 20 fs.The black circles in FIG. 12 indicate the respective color subcarriers.Also, in FIG. 12, area A.

indicates the approximate range of the C signal. Next C two vertical H
The characteristics of PFg01 will be described.

Vertical HP F 8θ1 frequency! The l:i property is the same as Hcomb (f (HZ)) shown in equation (2), and when expressed using the vertical frequency F, Hcomb (F5=÷(1-cos (2yr f v
−F/fH) ) = (3). The characteristic given by equation (3) is that the horizontal frequency direction C is constant and changes only in the vertical frequency direction, and this change is due to the fluff of F = 0.
The passband of the in 801 is indicated by the dotted line l! in FIG. and dotted line I
(dotted line 1 + is F=0.25fH/
fv, dotted line l! is F = 0.75 fH/fV is 1
In order to repeatedly target the 1-pattern for each line, the filter using line correlation is F=0.5fH//■ (dotted line J,
) has the characteristic of folding back (mirror symmetry). 1$8 In the figure, the output signal 806 of the vertical HPF 801 is this signal (
In order to remove the C signal component (area AI in FIG. 12) included in the signal T and P F 807 . L P
Fe12 is composed of 2Ts delay circuits 5ott to 81, coefficient multipliers 4812 to 816, and addition circuit 817, and has a low frequency 7Ai overcharacteristic with a band of about 1 (MHz). Due to this characteristic C2, the C signal included in the signal 806, including its high frequency components, is almost completely removed. The passband of the filter in which vertical HP F 8θ and LPF807 are connected in cascade is as shown in Figure 12! This is the area indicated by , and this is the vertical contour signal J77? l The two aspects are hidden. If the removal of the C signal is incomplete, applying vertical contour correction will cause C dot interference in areas with large color changes, degrading the image quality.

Another method for obtaining the image/p contour signal is to perform vertical HPFI on the Y signal itself.

However, the Y signal generally has a wide band, and this
．． If the C signal is passed through the vertical HPF', the leakage of the C signal becomes significant, and dot interference is likely to occur. Therefore, in this embodiment, the LPF 807 with a relatively narrow band and the vertical HP
P801 is combined to create a vertical contour signal 81g separately from Y (H No. I31). This vertical contour signal 818 is generated by a multiplier n
After being multiplied by and dyne Ill, it is output as a squared iα contour rectangle 708.

(2) Horizontal contour circuit FIG. 9C shows the configuration of the horizontal contour circuit 702.

The horizontal contour signal 709 is generated by the 2TR delay circuit 126 and the horizontal contour circuit 702C. This can be thought of as a cascade connection of a vertical T, P F 901 and a BPF 907 in a comb filter configuration. Vertical I, P
F901 is 2Tl (delay circuit Rr126 and coefficient multiplier 9
It is composed of θ2 to 9θ4 and an adder 905, and has the opposite characteristics to the vertical PF 801 in the horizontal 48 diagram described above. =±(l-CQS(2πfV-F
/fH)), and this passband is shown by the dotted line in Figure 12! , the lower region. (Actually, there is also f2 above point m11). It is input to the vertical LPF 907. BPF90
7 is a 3Ts delay circuit 908,909 and a coefficient multiplier 9Iθ
912 and an adder 918, and has a center frequency of 2.2 MH2), , 4 ordinary bands (NTSC'
It has a characteristic of 60.9NH2 for PkL and 1.1MHz for PkL. This is a filter for extracting the horizontal contour signal of a picture that exists near 2NH4. Vertical LPF
The J band of the filter in which 9θl and BPF 907 are connected in cascade is the J2j&Jl+A, -L6 region shown in the figure, and this becomes the horizontal contour signal 9no4.

Normally, when obtaining a horizontal contour signal, the Y signal itself is
M) (1), which leads to H 71 F whose pass band is centered around Z, and there are many 1 filter. Shigashi Y (H number is vertical i+'+,
The Md wave number also has a relatively wide band, and C(
No. H (area At in FIG. 12) leaks in more. For this reason, since applying horizontal contour correction≦2, dot disturbances are permanently caused in areas where the color change is large. Therefore, in this embodiment, a BPF 907 for extracting horizontal contour components,
Vertical I, PF and θ to suppress C signal leakage
1 to form the horizontal contour signal 914 as numerator +It. This horizontal contour signal 914 is multiplied by the horizontal contour control signal 705 in a multiplier 915, and after the gain is adjusted, it is output as a vertical contour signal 709.

(3) Contrast circuit An example of the configuration of the contrast circuit 703 is shown in FIG.
i) Consists of F'z soy and multiplier 1309. The characteristics of the contrast circuit 703 are the integration circuit 1301,
A) By using the average value circuit 1303, it is possible to prevent the direct current component (prite signal) of the dihedral image signal from leaking into the contrast signal 1308. This eliminates the inconvenience of changing the prite when adjusting the contrast.

Next, an outline of the operation of the contrast circuit 703 will be explained.

2'J'') rOTMM output from the delay circuit 126
The extended signal 404 is input to the integrating circuit Z 301 and
The image portion during the horizontal period is integrated and the integration result 1302 is output to the average value circuit 1.103 during the next horizontal period. The average value circuit 1303 divides the integration result 1302 by a predetermined value (the average value 1.904 of the 0 image part is output to the operator 1306).
is the average luminance within one line (corresponding to two). Subtractor 13
05, from 2T+t4 grinding circuit 126 I T )T
, 1% extension signal 4056 human power is generated, and from this signal image t+
1! The average value 1304 of the minutes is reduced.

Therefore, carpet 1! As a result, a variable current portion 1306 of the image portion is obtained. This AC component 1306 is horizontally C2'1
-0) DC component is removed.

Therefore, in the #412 diagram, the transfer characteristic from l T 1# extension f iris 405 to this y flow part 1306 is 0 in the horizontal frequency f20 portion (on the vertical frequency axis) and l in the other portions. becomes.

Note that the average value 1304 of the QIllo delay signal 404
is output along with IT)i, so in the subtracter 1305+U, in order to match the phase, ITI(delayed signal 40
A subtraction is performed between 5 and 5. Contrast and #yo are changes in brightness over a relatively large area of the image.
The second video corresponds to the low frequency component of the i video.

So this low frequency component is L P F J ,? 0
7 to be extracted (from the second, contrast 16 No. 13
08 is obtained. This contrast signal 1308 is multiplied by ¥! ′? rxsoyt2, the signal is multiplied by a contrast control signal 706 and amplitude adjusted, and then output as a new contrast signal 710.

Next C: Detailed explanation of each circuit in FIG. 13.

Integrating circuit 1301 includes adder 1311, latch 1, ?
It is composed of J j , J J I J. latch 13
12 performs a latch operation with a sampling pulse 116;
The output is cleared to zero during the flyback period by the flyback 74 rus I, q4. Therefore adder 131
Wrap the output of 1 J,? Input to J J, latch 1
By returning the output of adder 1311 to the input of adder 1311, OTH delayed signal 4041. On the other hand, the integral during the image period (
cumulative addition) is performed. Since the latch 1312 operates with the sampling pulse 116 (φs), the adder 131
The addition at 1 is performed every T8C, and the number of additions NA in the entire kernel period is NA (TH-TFB)/T8 (TFlt flyback time). On the other hand, Ratu f
131 J wraps with Flyback No and Luz 134-
To carry out the operation (2, therefore, the output signal (fR minute result) at the time when the rat y-1312 is cleared from the flyback node 41/res 134 (2) is outputted, and this is integrated as an integral result of 13 oz and sent to the average value circuit 1303. The average value circuit 1303 is a circuit that divides the input integration result 1302 by NA ((1-, multiplication) and outputs the result A.The NAO value is TFB=0.2・T
I(.

']'H=910 ・Ti(NTSC), T
F! When the total R is calculated using =1135·Tl1(PAL), it becomes. In the actual performance, the number of elements is reduced by 1 (4), and the performance is approximated by the sum of powers of 2.
2. 2 (7) Coefficient multiplication; fi unit 1. ? ,? J.

1.9,? , 1 , I J , ? J only needs to operate the wiring, and the only hardware actually required is the tile adding circuit 1334 and the 3.5. Goo)
IJ,? 5 is the NTSC/I' input switching signal 14
6, and in NTSC mode, calculates equation (5),
In order to (add the output of the -2 coefficient multiplier 1333!
In the FAT mode, the output to the C adder 1334 is set to zero in order to calculate equation (6). In addition, the error due to the above equations (5) and (6) is 2.2% for NTSC,
F A T, 02%, no problem in practice, LPF1
307 is the LPF #07 (bandwidth 1mm (I) shown in FIG.
The same one as I z ) is used.

This (second) separates the contrast signal 1308 from the horizontal contour signal 905 (area As in FIG. 2) in terms of band.

In this way, the integration circuit 130 and the average value circuit 1303 are realized with relatively simple hardware, and the leakage of direct current components into the contrast signal 1308 can be eliminated.

(4) Bright adjustment Figure 7 (2nd, brightest) l, 1st section is adder jY device 71
1 and a pedestal clamp circuit 713. horizontal,
Unlike the vertical contour and contrast IAI clauses, brightness adjustment only needs to be done by controlling the DC component based on the image bedeskle level, so the brightness control signal 7
07 is the Y signal J from the adder 111 (2 directly inputted, and other signals from the C2 Y/C separation circuit 128, 9
Jc is added (1) and a Y signal 712 is output. But is this enough? The ideal level of the output (1) of the YIM signal v and z of the signal generator 711 is also converted to i, and the DC component of the image portion seen from the ideal level remains the same as the Y signal 13. Therefore, in the pedestal clamp circuit 713, the fly
Tsukunohira Rusu 134 (Flyback N1 middle Y
The signal 712 is clamped to a certain ideal level of PJ and a Y signal 13.7 is output. As a result, the average brightness of the output Y signal 133 is equal to the average brightness of the input Y signal 13)
1C, it changes by an amount corresponding to the bep light control signal 707.

The bright sub-tube is performed using the above procedure.

(Color m: 7 control color killer circuit) Color control color killer circuit 1.75 Tachibana Naru example @1
Shown in Figure 4. The functions of this color control/color killer circuit 135 include the input C signal 130 (performs two-pair ACC, manual color control, and color killer operations, and also supplies a color killer signal 137 to the Y/C separation circuit 128). However, as mentioned above, when C: Color Kira series is executed, the video signal 422 in FIG. 4 is output as is as the Y signal 13).

The color control/color killer circuit 136 includes a multiplier 1401. Color killer circuit 1409, perspective)
It is composed of a seat detection circuit 1404, a loose filter 1408, and a subtracter 1406. The outline and characteristics of the operation will be explained below, and then each round will be explained.

The manually inputted No. 016 130 is led to the multiplier Jq generator 14014, and is multiplied by the No. 016 1402 to perform amplitude control. C signal 140, which is the output of the multiplier jQ,
3 is input to the burst amplitude detection circuit 1404, and the amplitude term of the color burst is detected. That is, a value proportional to the color burst amplitude (-) is calculated by 1*. The calculated burst amplitude signal 1405 is inputted to the "Decrement if!" 41406 (21.).

This v2n device 14θ6 performs WQ differential A:, in which a burst oscillation 1 bit 1405 is input from the manual control unit 136 to adjust the ACC target value, that is, the color saturation applied from the outside. I-A, SA-R
, NCCHq difference signal 1407 are output. This AC
The C error signal 1407 is a loop filter 1 consisting of an LPF.
408. This loose filter 1408 is A
It determines the CC time constant, and the time constant is usually a number of 10.
T i (≦2 is set. The output signal of the loop filter 1408 enters the multiplier 140 as the ACC signal 1402 and is multiplied by 5 (20 (rT 130) as described above. In this way, the ACC loop is Multiplier 1401 → bust amplitude detection circuit! 814θ4 → subtractor 1406 → loop filter 1408 → C signal 130 formed and inputted in multiplier 1401 (7) TM II'+m'
It is controlled to have the magnitude of the ACC target 11α given by the manual color control signal 1.96, and is output as a new f2C signal 138.

The following two features of this color control circuit hS
It can be raised. The first is to operate the ACC' target value from the outside and perform color control from this C2.
The second method is to detect the amplitude of the color noise signal in NTSC mode. Depending on the value of Q1,
FAI, mode 1c-j-ul-1-l C1vl
This is done from flt +2. (C02CQ,
CrJ, CV is Azo Jl, I, Q, U,
3) In the past, the advantage of performing color control by changing the λCC target to 1 is that the color control [dedicated multiplier for Fool] There is no need to have it. Regarding the latter C2, the use of the sum of the absolute values of sampled values on two axes C2 whose phases differ by 90 degrees is necessary in relation to hue control as a method for detecting the amplitude of the burst. That is, the hue control is performed by changing the phase target value 117'4f and changing the sampling phase of the input DC 109 in the circuit 2001 shown in FIG.

The problem here is that the sampling phase changes (because of the second, the sample value of the burst part also changes, causing an incorrect burst amplitude value of 11g to be output. As a result, the value of the CC signal 1402 changes, and the magnitude of the C signal 1403 changes accordingly.In other words, changing the hue (secondly, the color saturation also changes.In order to prevent this, the Phase target value 11
7, it is necessary to take measures to correct the value of the burst amplitude signal 14Q5. However, this hard moment becomes large.Therefore, in this embodiment, the hue control (the color associated with two, !) is large.
As a simple method to suppress the change in the sum degree to a level that does not cause any practical problems, detect the amplitude of the color burst as described above (1c).
: r l + lc + -q l or Ic + tr l +
I'm going from C din vl + 2. According to this, the sample phase can be adjusted from the I, Q axis or (1, ±10' from the V axis).
(Hue variable range) Even when shifted, the detected burst amplitude value is n5.2%.

There is no practical problem with just a 1.5% penalty.

Next C two-color killer (I will explain it in two parts. Condition t41 for general C two-color killer to operate, input C signal 130)
) is less than a certain value. However, in this embodiment, by utilizing the fact that the value of the ACC signal 1402 is inversely proportional to the magnitude of the C signal 130 to which it is input, the operating condition of the color killer is determined when the value of the ACC signal 1402 exceeds a predetermined value. However, even for the human input C signal 130 of the same magnitude, the manual color control /l/4 is proportional to the magnitude of No. 136, and C, ACC
Color killer 111 because CC signal 1402 is repeated.
1) In order to keep the printing conditions constant (2) the predetermined value must be proportional to the magnitude of the manual color control signal 136.
(- indicates that the AC'C4nCC signal 1402 and the color control signal 1.16 are manually input, and the value obtained by multiplying the manual color control signal 136 by a constant (predetermined value K) and A
C(:' Compare the value of signal 1402 with the value of human CC signal 1
When the value of 402 is larger, the color killer is operating. When the color killer operates, the C signal 1
38 becomes zero, and the Y/C separation circuit 111 Z # (in the second case, the video signal 424 is directly output as the Y signal 13), widening the band of the Y signal 131. Note that the color killer operates according to the above-mentioned operation criteria. The advantage of using LPF + to detect the size of the color burst of the input C signal 130 and set the time constant.
The normal method of setting the color killer's operation standard to when the output value of this LPF is equal to or less than the P9r constant value requires only a simple circuit.

Next, the circuits of each part shown in FIG. 14 will be explained in detail using FIG. 15. In FIG. 15, the burst amplitude detection circuit 14
04 is a burst sampling circuit 1501 and an absolute value circuit 15
Consists of 02, Latte 1505, and 1506.

The rI4 function of the burst (board width detection circuit 1404) is the color burst (6
Set the period C2.21. ), the absolute value is integrated and the result is added to the quantity subtractor 14Q for one horizontal period (To).
6. That is, S multiplier 140 to noc, IH number 1403+-1, burst extraction circuit 15
01 (f- at 2-step extraction pulse 111)
be done. As a result, a signal (24f sample) for Kalan 9-stro periods is extracted, and the absolute value times y8i 50
j! is input to. The absolute value circuit 1502 judges the sign of the input color burst signal, and if it is ``1'', the data is inverted, and if it is 1'', it is 14
In operation f2, the absolute value of the color 9-st signal is calculated and output. This absolute 11-way signal 15θ3 is divided between the adder 1504 and the latch 1505 (2) during the burst acquisition period 111.
505 performs a latching operation with a gimping pulse 116, and the output is cleared to zero outside the period of the waste extraction pulse 111. Then, the latch 1505 is cleared. The value immediately before the signal (integration result) is latched by a latch 1506, and outputted as a burst amplitude signal 14θ5.

The loop filter 1408 is a circuit that determines the ACC time constant, and includes a 2 coefficient power N unit 1507, an adder 1508,
Ratsu y-1509, underflow prevention r91 road 151
Consists of 0. Among these, underflow prevention circuit 1.
5 J O has a negative ACC signal 14oz (ICE +=
This is to prevent this from happening.

Mata, 2-” coefficient 9A calculation S 7 s o v ha wiring v
No actual hardware is required, just a shift of i bits to the LSB side. Note that the wrap 1509 performs a latching operation from the burst extraction/4th pulse 111C2. In the loop filter 1408, the input error signal 1
Multiply 4Q7 by 2 and add this to adder 1508 and wrap 15
From 09g2, it is accumulated (integrated) for each TH. This results in
Sudden changes (high frequency components) in the error signal 1407 are absorbed. In this circuit configuration, the ACC time constant 2 ・T
Proportional to H. Therefore, by appropriately setting the value of n, the input CC time constant can be determined to a desired value.

The output signal of the loose filter 1408 is the ACC signal 140
2 is input to the multiplier 1401.

In the color killer circuit 1409, as mentioned above, CA C
Control 1 uses the value of the C signal 1402 and the value obtained by multiplying the value of the manual color control signal 136 by a constant (2) using the multiplier 1511 (151-2 for the color killer threshold).
513, and if the value of the CC signal 1402 is large, the color killer signal 132 is generally set to 0''.

This is the C signal 138 which is the output of Dart 1514 from f2.
becomes zero. On the other hand, at this time, the output C signal 422 of the C signal gate 42I in FIG.
Video No. 18 424 is output as is as Y signal 1,71.

(color demodulation circuit) Figure 16 (Shows an example of the configuration of the two-color demodulation circuit 139.

The color demodulation circuit 139 has latches 1601, 1602°16
05~1607 and 160g
~1611 and a dirt circuit 1613 including an innotator 1612. In the function of the color demodulation circuit 139 in the NTSC mode, from among the input C signals 138, the ■ phase data is latched 1601L-) and the ■ signal 1603 is selectively recovered by latch 1601L;
, +J
It is to demodulate the data.

In PλL mode, for the U signal, U phase data from the C signal 138 is wrapped in the latch 1601.
As a result, the U signal phase lty os is demodulated. on the other hand,
(2) As for the signal, since the modulation axis is reversed every line, it is necessary to switch the latch position by "V t "-V for each line when demodulating with the latch f1602.

This switching is performed using the PAL identification signal 206.

Next, the actual circuit operation will be explained.

C signal 138 is input to latches 1601 and 1602. On the other hand, the reference phase pulse 206 generated by the phase detection circuit 118 is also inputted by the color demodulation circuit 139f. The reference phase pulse 206 is a single-axis phase pulse C2 (in NTSC mode) or FAI.

In the mode, the U-axis phase is set to 4. Reference position 4
The second pulse 20g is input as a lattice pulse to the wrap 1601 as it is, and here the I or U phase data from the C (i signal 138) is latched, and the ■ signal or U signal 1603 is demodulated. The pulse 2θ6 is sequentially shifted in phase by 1 sample (90, I) by the lattes 1605 to 1607.
From 1605, -Q or V phase/IF pulse is applied to latch 1.
From 606, -■ or -U phase normals are wrapped and
1507 outputs a Q or -■ phase pulse, respectively. And NT8C/PAL switching 1g No. 146, P
A L identification signal ZOS and latch 1605,
161 which takes the output signal of 1607 as input.
3) A Q, V demodulation pulse 1614 is created,
This data is supplied to rat f1602. The Q and V demodulation pulses 1614 are used when the NTSC/PAL switching signal 146 is NT
When in SC mode, it is Q phase no
U, di+■ or 1■ phase pulse. This (−
Therefore, the demodulated Q1 signal or ■ signal 1504 is output from the latch 1602. In addition, the dirt circuit 161
3, NTSC/PAL switching A No. 146 is NTSC-
E-)" TOlFAI, mode is 1, and PAL ID number 4-2θ5 is 1 on the +V axis. The configuration is shown when the -V axis is O.

The demodulated C signal 1 outputted from the color demodulation circuit 139 in this way
41 is a mini matrix circuit 142 along with the Y signal 133
and an RGB signal 142 is generated by a predetermined matrix operation.

Note that the calculation contents of the matrix circuit 142 are NTSC/
Switching is enabled by the PAL switching signal 140.

Although the present invention has been described above, the basic circuit configuration etc. are not limited to the above embodiments and can be modified in various ways. Furthermore, it goes without saying that the television receiver according to the present invention is effective not only as a receiver for receiving broadcast signals, but also as a so-called monitor receiver.

[Brief explanation of the drawing]

The figure is for explaining one embodiment of the present invention, and T@1
The figure is a schematic configuration diagram of the entire image processing circuit, and Figure 2 is Pl, L.
Figure 83 shows the configuration of the circuit, Figure 83 shows the color burst sample points, Figure 4 shows the configuration of the Y/C separation circuit, Figure 5 shows the characteristics of the comb filter, Figure 6. is NTSC/FA 1. FIG. 7 is a diagram showing the configuration of the Y signal processing I11 circuit, FIG. 8 is a diagram showing the configuration of the vertical contour circuit 1, and FIG. 9 is a diagram showing the configuration of the horizontal contour circuit. , 101 (shows the relationship between images and horizontal and vertical frequencies); Figure 11 is a diagram for explaining two-dimensional frequencies; Figure 12 is a diagram showing television signals in two-dimensional frequency format. , FIG. 13 is a diagram showing the contrast circuit, FIG. 14 is a diagram schematically showing the configuration of the color control/color killer circuit, FIG. 15 is a diagram showing the circuit in FIG. 14 in more detail, and FIG. It is a diagram showing the 1'?? configuration of the color demodulation circuit. 101... Analog video I Δ code, 109... A/
D converter, 110... digital video signal, 12
6...Delay circuit, 128...R/, degree signal/chromaticity signal separation circuit, 130°...chromaticity signal, 131...luminance signal, 4θ1... (type IIIi), ilta, 412・
... Bandpass filter, 420...NTSC/PA
T, switching circuit, 423..., 1.1 delay circuit, 4
25°°・reduction) ψ device.

Claims (3)

[Claims] (1) Video Ura-go Kefunotalization] 7 constant 1 duplication, signal processing y'notal TV Noyon Uke +1! +1, the denotal video signal is input, and the J +
Horizontal rk 3 lights each time 1st. Delay 10 to output multiple delays 1=signal! l j! 8, and the plural a-duration signals C2 output from this delay circuit are subjected to a predetermined Hamasa, and the result of E's operation yX is output. Frequency, n is an integer) and dyne is 0, f = (n0) fTl and dyne is l
, f = (n±+) A comb filter having a frequency characteristic of 0.5 with fH and the output 4 of this comb filter.
A band-pass type filter with f = fsc (fsc is the color subcarrier frequency) and dyne of 1, which inputs the M number,
The output signal of this bandpass filter is '4' when in NTSC mode, as it is; when in PAL mode, the value is doubled and output as a chromaticity signal.
A I, switching circuit and color 1 output from this switching circuit
an n-degree signal/chromaticity (N number Separation circuit. (2) The comb filter converts the delayed signal of JL which is output from the delay circuit into a delayed I! ri, l1 from the smallest hoe
9. C1. When ν, these signals ν. . ν1. ν, for −+ν, 4−. LνI --) v!
1. A luminance signal/chromaticity signal separation circuit according to claim 1, wherein the luminance signal/chromaticity signal separation circuit performs a certain dance and outputs the calculation result. (3) In the band-pass filter, the output signal of the comb filter is C1, and the time 1/4 fsc is calculated from this signal C6.
When the delayed signal is CI and the delayed signal is C7, the luminance according to claim 1 is characterized in that -chico+cj -rcy is calculated and the result of the calculation is output. Signal/chromaticity signal separation circuit.