JPS60120690A - Chrominance signal processing method - Google Patents

Abstract

PURPOSE:To improve the band and the group delay characteristic of a regenerated chrominance signal and to improve the picture quality by making the filter unnecessary or releasing the design terms to be used when a low-band conversion carrier chrominance signal is converted to a bottom-band chrominance signal. CONSTITUTION:A low-band conversion carrier chrominance signal CL, which is recorded and regenerated by a color-under system, is added to balanced modulators (B) 5 and (R) 6, and the outputs are converted to B-Y and R-Y signals which are bottom-band signals through comb-shaped filters (B) 9 and (R) 10 respectively. The signal of a subcarrier frequency fL of the low-band conversion carrier chrminance signal CL is added to the balanced modulators (B) 5 and (R) 6 by shifting the signal fL from signal fc by 90 deg. in plase by a phase shifter 7. Thus, the unnecessary side-band components, which generate when the low- band conversion carrier chrominance signal is converted to the bottom-band chrominance signal, are removed by the comb-shaped filters, and therefore, an LPF and a BPF which have the sharp cut-off characteristics are not necessary, and the wide range of the chrominance signal band can be held.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for processing a low frequency conversion carrier color signal used in a video tape recorder (VTR).
In particular, when converting a low frequency converted carrier color signal from a VTR to a baseband color signal, or at a predetermined color subcarrier frequency (approximately 3.5 s M in the case of NTSC)
The present invention relates to a processing method when converting into a carrier color signal having a carrier color signal (Ilz).

Conventional configuration and its problems The color signal recording method of recent consumer VTFts converts the carrier color signal to a low frequency band and records it by frequency multiplexing on the lower side of the frequency-modulated luminance signal band. This is a method called color under. Although this method has many advantages, such as being strong against chics caused by rotating cylinders and the like, and having good linearity as the FM luminance signal is used as a high frequency bias, it also has the following drawbacks.

Figure 1 shows the central part of the color signal reproduction thread in conventional color under recording (parts other than those related to the present invention have been deleted). This shows the VH3 system. OL in FIG. 1 is a low-pass converted carrier color signal reproduced from a VTR, and this is converted into a carrier color signal of the NTSC system, Csc, by a main N+” balanced modulator 1 and a bandpass filter (BPF) 4. Converted.In this case i″)・
, one carrier C11, CL to the conversion applied to the ten-scale modulator 1
er 29 KIIZ, which is the subcarrier frequency of ! :
3,58 Mllz and ke subcarriers of Cso!
14 negative modulator 3 and χ, which is the frequency of the sum of both tones, 4
, 2 M +17. Bread 1 - Bath fill (BaF
") 2 to pull out and i ↓).Here, join the vice balance modulation domain 3 e 29 K l1zi (IvT R (7) 111
/14i';Yumi no Mizu Il' 1ril JIJI4N
As is well known, the 3.58 M 1lJj Gso Herme 1-signal is configured to be applied to the 1-4 and 7-signals, respectively.

Figure 2 is a Mebek I-zum representation of the frequency conversion.
(a) (Bow: Low frequency conversion conveyance
9KIlz 500 K 1lZJ1. '
It is a signal with a band of i' degrees. In (b), the difference and sum components of the conversion carrier f0 (4,2M1lz) and CL are output at the subbek 1-ram appearing at the output JJ of the main flat box modulation circuit 1, and (C8o and C・sc ), of which only the necessary CSC is reduced to (C) jj
Hashi 1゛ with 111 bus fill, 11y, did not come out.

In this case, the C2S O, which is a second sideband wave, becomes an interference, so the bandpass filter requires strong blocking characteristics on the high frequency side. However, depending on the characteristics of the balanced modulator 1, gear leakage may still occur. It is necessary to have a blocking characteristic that sufficiently attenuates the components. In this way, the bandpass filter (BPF) 4 is required to have a steep cutoff characteristic, so the pass band of the filter tends to be narrow, and in that case, the band of the reproduced color signal is narrow, and the color This causes image quality deterioration such as blurring. Furthermore, a large group delay distortion occurs within the passband of the fill, resulting in deterioration of image quality.

As shown in Figure 1, in the conventional color under color signal recording system, the pan 1 and bus fill 4 used when converting to a carrier color signal are not used for scales that require strict performance, but for color under color signals. Kawauchi was a person who was concerned about signal deterioration.

When it is necessary to output a color signal in the base band, the conversion carrier f is used. 629KIIZ is fine, but in this case as well, the gear rear f is used in addition to the base band color signal. Since the upper side wave component appears, a low-pass filter with a steep slope of 100 to 1000 yen (-) removes it, but there is a problem in A-League that it immediately reduces the deterioration.

12, low 1 or conversion conveyance [θ believe (i・I
11 Installation of soil legs that should be avoided or used when converting to the bottom band or the specified 1 color number, 1
Article (loosen /l, rl): 41 colors I R obi 1p
g: l+・Yojiru 1j・1, extension '4', '+1. <l
The purpose is to improve the ``prii'saturation.''

Structure of the Invention In the present invention ":ru color (5i'-"D treatment H//: it,
Divination from the low band conversion carrier color signal (bottom band color 11/11/8) L <&: I, 51. 'Carrier color that determines the subcarrier frequency (+'r Change to %11C)
[S, low range change] moxibustion 1 general color I 1-shizu repeated 1 times,'', (
11't.) By configuring the 11 bow or 1-1 to pass through a comb-shaped filter, it is possible to remove unstable sideband components that occur during demodulation, and to remove sidebands that occur due to conversion. The Ij-pass or bread 1-pass fill can be deleted or replaced with a loose 'I', so that only 1 raw is required. .

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 3 is a block diagram of a color signal processing method according to an embodiment of the present invention. The low-pass conversion carrier color signal C1 recorded and generated by the color under one-way system is passed through a 14-balanced modulator (B
)5 and o: are added to the
and Q; converted to RY. Balanced modulators (B) 6 and (R) 6 are supplied with a signal having a sub-first wave frequency f of the low-pass converted carrier color signal CL, and a shifter 7 converts the sum difference by 1 of 90. Here, balanced modulators (B) 5 and (R) 6, phase shifter 7, conversion carrier fLQ, 1
, ■ Form the moon ν9fi device 8.

FIG. 4 is a diagram for explaining the operation in the configuration of FIG. 3. When the baseband color signal, which is the original signal, is expressed as fB, the low-pass converted carrier color signal CL has a subcarrier frequency of 11 (629 K in the case of VH8) as shown in FIG. 4(a).
Ilz -1-% f)I) It consists of fL-fB acid components fL and f8 components. Along with this OL, a subcarrier f is added to the Heikoku Henko 1 device (B) 5, so Il
6tr, J:
The 11th place of fb is different by 90/ζ, but the other operations are the same, flV+! Omit the description. ), the sum and difference of CL and f are shown in Figure 4(b).
``Then, 1 minute is the output.
fL-/+1.2 f), -l-fB I+ for 5 minutes.

Among these, J store 1 is connected, (Sl) J'B is output (as soon as the B-Y signal is output, 2F','
/I figure tel shows small J', 1, eel 4゛, and sex l)
-Buff 7, (/l/') to A J-' It:U
, , 1-Squid, 1・The essential component 1= fEl wave or 17), so you can rest assured that the acidic filter with the political decision characteristic is safe. Let's do it together.

Therefore, in the present invention, the output comb-shaped filter 9 of the variable-tooth type regulator 5 is
1llj '11. It's resolved.

5Nd, comb filter (B) in Figure 3 9
: l = - and (R) 10, and the COD delay time to be moved by L D , 7 R / 1 device 12: 烙 11 and addition '1, ; 1 device 13. 416 have been completed. 1
．． ; The CD delay circuit 11 appropriately selects the frequency of the clock generator 12 and the number of transfer stages, and delays the signal by a time corresponding to 1/- scanning period of the video signal. Therefore, at the output of the adder 13, a sum of the human input signal and a signal obtained by delaying the input signal by 1H appears, and its frequency characteristic 14- is shown in FIG. )
Of course, the scanning frequency 11) has a peak, which is the so-called Y-comb filter characteristic 171-.

Now, the output of the ``1'' balance modulator (B) 5 in FIG.
Figure (b'+ (r(-signal with a small spectrum)):! II! Let's take a closer look at the spectral distribution.

Low-frequency conversion recorded in the power ° no under recording Itsu A method ") 艮j Wakabai J, \'s Denme Hannya Wave /, H1 Substance"
2nd f□'s odd number ia', I, Pkoi%' (d:
ftd
(The subcarrier recorded on the tape is different from the actual subcarrier): Substantially -11, adding ilh'a to the above relationship). Therefore, the conversion charge added to )6 of the IL balance modulator is
The frequency fL of a is given by the following equation.

/L= L< fll(2n -1) ---(1)/
Hi Suikosho t1 - Frequency n, integer/Koko, demodulated/ζ'1 (Bottom band I symbol iJ:
The spectrum is expressed by equation (2) and has a peak at f, , 'D), as shown by fB in FIG. 6(b).

/B=tn. /H---・(2) 771: Upper side wave 2fL-fLl of integer fL and 2, /,, 4f
Substitute 1, (1) and (2) for n fly -j
゛And the soil↑! i1-), l1, (s), (
4) In equation 1, we have a small scale 1-)v.

2fL-fB-1≦IH(2F4-1) ・-, (3)
2/,l-fB=%/H(211+-1)-
-(4) N,'b'i; Integer These spectra are interleaved with the spectrum of fB. 4-li, of the outputs of 5) of the example modulator. (The bottom band signal fB and the unnecessary component which is the l(rlll wave) are in an interleaved relationship.

Therefore, as is clear from Figure 6, as already explained/
By passing through the Y-shaped comb-shaped fill letter, fB, which is the number 11 bottom band, is outputted, and the unnecessary components 2f, -fB and 2fL+fB are removed from the 11-region of the comb-shaped soil filter. Since there is only subbek l− /,
l,,K<tod is reduced, and in the end, JJ,1. is sent to the output of the hidden filter 9 by the null vector (li) as shown in FIG. 4(d). , this signal can be extracted as fflR-, Y Qj, and the remaining ±1 is -j/.c +・1゛・
The till wave is further e. In order to express it, in Fig. 4(e),
J-, a loose I-I-pass filter '. n'
+1, you can take it out. In this way, the baseband signal Q
By passing the demodulated baseband signal through a comb-shaped filter to pass B-Y to 7LF, it is possible to largely remove undesired components, and it is possible to eliminate the need for a low-band filter or one with mild characteristics. The 74 band is wide and the color signal with small distortion can be output within 1/1.

” Second Ki Kh! Akira explained the conversion to B-Y, but
Half-picture modulator [F]) 6 and comb type F (/ref (R) 1)
0 can be converted to R and -Y in exactly the same way.

Next, N
A case will be explained in which the transport color is changed to the TSC and the constant i%.

Figure 7 is a configuration diagram showing the usual ability of the mountain/I.
The low frequency conversion transport p2 signal G, kl (!:i adjustment 1Δ, converts the color of the bottom band to 4ij' ``j-, and removes the low Iltll wave component. The point J where the comb-shaped filler 16 is arranged f<i is similar to the embodiment of FIG. 3, and the output t1 of the comb-shaped filler 15 is 1\14 The output is applied to simple modulators 17 and 18 and outputted through 20 modulators. 9-core 7-ten differences in the eye lX wave frequency fsc: by Kupkoi 1 Ishiba ■ and Shunwa Zofuku 19)
Ru. In this configuration: two Jll. Quadrature 2-fold modulation of the subband color f is performed, and in the case of N T S C, fso
= 3.6 by setting 3 6 8 Mllz
A carrier color signal of 8 Mllz is obtained.

FIG. 8 shows the manner of conversion to a carrier color signal in the form of a block diagram I). (&) is the low-frequency conversion carrier color signal O of the input J.
In the nuvector of L, the subcarrier □ transmission frequency f. ．． The distribution is centered around. (b) is the spectrum after converting to si (base band i) No. 3 and passing through 9 comb filters, and the base band signal fB
There remains a small amount of disturbing sideband components that could not be removed by the comb filter. (C) Shows the spectrum obtained by converting 11 to the subcarrier frequency f, using a Sasagu modulator, and shows that the carrier color signal centered on fsck is almost the same, with a slight side band at the bottom. There are only waves.Therefore, it can be taken out as is as a transport color signal, or it can be taken out through a loose 1-pass filter as shown in (1).

Comparing this with the conventional example explained in FIGS. 2(b) and 2(C), it is clear that there is a significant difference in the distribution of subek l-'/d after conversion to a carrier color signal. A filter to remove the signal is unnecessary or necessary, but the carrier Ci'-; It is possible to do a picture π (conveyance color G:!'jJ donkey J) with good IC7 without undergoing deterioration.

Figure 3 or 1. Fruit of the present invention according to FIG. 8) 40! , 12]
In 1, the low range variable one-sided carrier color Iha bow is j, Q 1 band] or the variable 11 (υ) (-7 type fill) 1fiL,
It is important to remove uneasy sideband components that occur during demodulation.
This comb filter indicates that it is effective.
VH3 and Beta force type and Ashimame type commercial secret; V' T Rf according to ship record is 1 inspection I-rack glue 11 nost-removal / can also be used as a comb filter required for rice + iJ function . In the conventional example shown in FIG. 1, the output of the main 14-balance modulator 1 is mixed with the adjacent 1-to-rack 1-fmetre component, which changes the relationship between the main signal and the ink league. - After converting to a bow, the comb-shaped soil reflex is shaped using a horn delay line; L, the croix and 1-re components of this adjacent 1-rack are removed. 7.1 to this
When the present invention is applied to azimuthal high-density recording, the Xl/equilibrium variable J1.1 device (B) 6. However, (d
Adjacent crosstalk components are added to the main signal component of the baseband while maintaining an ink-IJ-b relationship. In other words, since the adjacent 1 to 5 crosstalk components are on the same spectrum as the sideband components generated during conversion to the baseband signal, the comb filters are 9°10, i5 and 0. At 16 they are removed simultaneously.

Moreover, these comb filters can be used for baseband signals as shown in Fig. 6, so they are COD.
It is easy to use a conductor delay circuit, and it is much more practical than considering expanding the band of a conventional Crow delay line. This is also one big cow Ij according to the present invention.

Although the above-described embodiments mainly concern NTSC, the present invention is also sufficiently effective for, for example, PAL system VTRs.

In a PAL system VTR, the subcarrier frequency of the low frequency conversion carrier chrominance signal is selected to be an odd multiple of Nfl, as shown in Equation (5) in contrast to Equation (1) in the case of NTSC.

/L-/ /1. (2n-1) ・、、、、、、、、
,,,, (5) N3 and N4 (generated after conversion to the bottom band) are two side waves 2f'1, -fB and 2f', -1/Bil, (
6) It is shown by the formula.

2/'L- to fB"'!/Ban fH (To-1)...-
...(6) It shows that the sideband component which is different from Equation Q in (6) is aligned with the baseband signal, and there is a relationship of % fin off so 1. ], it can be removed with a comb filter containing a spreading circuit for 1 hour or 2 hours. In other words, by changing the 1H,<L-type filter in the case of NTSC to 2) 11°'1' to 1 comb-shaped soil reflex, it can easily be applied to the PAL system.

Effects of the invention 1 Is (: ゛When converting to a carrier color signal, J, 1.
- The unbalanced ir (Ill) band wave component that occurs during demodulation of the bottom band J or \ is removed using a comb-shaped filter in the Jl (bottom band). '(j'
t Z) By eliminating the need for low-pass fibers and non-pass filters, the color (N) bandwidth can be kept wide and group delay distortion can be kept small, and the image quality of the reproduced color signal can be improved. It will be of extremely high quality.

Furthermore, when converting to a predetermined carrier color signal, the bandpass filter for conversion carrier generation (indicated by 2 in Figure 1), which was conventionally safe, can be eliminated and the carrier frequency can be used directly. This also has the effect of simplifying the second structure.

Also, the comb filter used may be one in the basal band.
Deciter/Vj using stop COD delay circuit and memory element
An ffl extension circuit is essential, and it is also suitable for miniaturization and for making low-frequency lids different from conventional carrier wave delay lines.

4. Drawing 1', Ii'lj 1, Explanation 1st Blasphemy 1.
In conventional low-pass conversion carrier color signal recording, carrier color 11'7
- Configuration diagram showing the main parts of raw silk for the bow, Part 2 [E1 (a) ~
(c) 1. A diagram that explains the appearance of frequency conversion,
FIG. 3 is a block diagram of main parts of a color signal processing method which is an embodiment of the present invention, and FIGS. 4(a) to (e) explain its operation.
The ξth spectrum distribution diagram, FIG. 6, is used in the present invention.
Figure 6 (a),
(1) j fcl, dynamic according to the invention ('V %: 1
! f1', clear frame (1) comb-shaped fill 4,',?
II! A diagram showing the relationship between I dos vector 1/l/, Figure 7 (in), an example of the actual %i of (jl2 of the present invention), a small-4' Abe configuration diagram, and Figure 8 fa) to (d) show its dynamics. ('1; 4r theory, pu(mebek 1-/l/l henchman j diagram).

5...Xk1 flight) Hengen Shu Bi (B), 6--Ushin J
Modulation 2); field), 7...-- Can shifter, 8. Color demodulator, 9- < L-type filter (i letter (13), 10.
Comb-shaped 5r filter (R), 11CCD slow 14 circuits, 1
2. ri 11 tsuku no l device, 13-= force 1 volt device,
1 4-fg? u? J! , I 2ii, 15
, 16. Comb filter, 1-γ, 18-u ii/
1f modulation 2;), 19...-Is adjustment, 20-
- ) Ill T:jl: 't! ”r'r,.

Name of one representative IJ: Patent attorney, Naka Jll, Toshio Q.
1 or 1 and 1QS 2nd figure: U Figure 4 @ 2rLzfL no phrase-k (jε father mi a) 5 Figure 6 Figure frequency Figure 7

Claims (1)

[Scope of Claims] (1) Low range conversion transport color - 11 (To convert the low band coloring bow into a base band coloring bow, restore the said low range conversion transport color Igo bow 14
shi, ), (comb shape against the bottom band Iha) - (/Ref is one,, the lust that is characterized by IQ is the place 1 (
IJ vise method (2) Record 1 mm in the comb soil used in the baseband.
ml-rack glue VJ stock removal), (bottom 1 ()
'l, '11r1 to use 111 to remove the 1111 kawave 1 minute of the beef star that is no I in 4-k, '11r1
．． ! 11
Reno method. (3) When the low-pass conversion carrier erotic transmission frequency image is
1 and 11) must include a delay circuit and an adder circuitf:
q, 'l Characteristics r1°; 1lli Search range 1. (4) The color subcarrier frequency of the low-pass conversion carrier color signal is “IB”
fH(2n-1), the comb-shaped fill is characterized in that it includes a 2H (horizontal scanning period) extension circuit and an addition circuit.
F. Color signal processing method as set forth in claim 1. (5) In converting the low band converted carrier color signal to a carrier color signal having a predetermined color subcarrier frequency, the 1 band converted carrier color signal is once demodulated; On the other hand, the color signal processing method 1.1.lj is characterized in that the comb-shaped fill is converted into a predetermined carrier color signal. (6) The comb-shaped fill used in the base band is azimuthal. Adjacent track distance on recording VTR "1 meter"
A color signal processing method characterized by combining the removal of unwanted sideband components occurring in the baseband with the removal of unnecessary sideband components occurring in the base band. When the color subcarrier frequency of the carrier color signal is , it is assumed that the comb filter includes a 1H (water \l'> j, 4 scan period) delay circuit and addition 111 circuit! I':ll♂1 The color signal processing method according to claim 6. (8) The color subcarrier frequency of the low-pass conversion carrier color A is 1'I
If B fH(2n -1), the comb fill is 2H (Suikoto Yui 11 period) slow ttt+[which includes a path and an addition circuit<'
:I'j sign 4, 1irj'l'δ]11*;1
No. 51-L'1: 1 method for using the color of the bow.