JPS58111595A - Color television signal transmitter - Google Patents

Abstract

PURPOSE:To improve the picture quality without generation of color dot interference, by transmitting a luminance signal and a chromaticity signal as an NTSC signal after sampling them in different frequencies. CONSTITUTION:A chromaticity signal from pickup tubes 111-113 is applied to a matrix circuit 12, and a luminance signal, a broad band chromaticity signal and a narrow band chromaticity signal are outputted from the matrix circuit 12. The luminance signal and the chromaticity signal are sampled at sampling circuits 131-133 in different frequency of sampling pulses and transmitted from an antenna 22 via low pass filters 161-163, an NTSC encoder 18, an adder 17 and a modulator 21. The signal is sampled at the sampling pulse synchronized with the transmission side at the reception side and the luminance signal and the chromaticity signal are reproduced.

Description

TECHNICAL FIELD OF THE INVENTION This invention relates to improvements in color television signal transmission equipment.

Technical Background of the Invention and Its Problems As is well known, band compression technology is progressing in the field of digital telephony. But analog TV-)
In W-band transmission, the current situation is that when the number of scanning lines is determined, a unique kvI interval is determined, and furthermore, there is no technology that attempts to narrow the band.

However, in the case of videophones, for example, bandwidth immediately affects operational costs and is a major factor inhibiting its widespread use. Also, television show.

In the case of digital broadcasting, radio waves are a finite resource, so they are subject to band restrictions, and waste is a constraint on image quality improvement.

Conventionally, the following methods have been considered for K to perform band compression. That is, l) performing band compression at the expense of horizontal resolution;
.

2) Change the field frequency by 9 in.

3) Change the interlace ratio. (For example, 4: RI. 2), s) is an integrated TV-) Changing the scanning method of the W may cause problems if the design of the existing TV receiver is used. , 2) For K, the 7-bit disturbance is increased due to the decrease in the field frequency, and 3
)k has the disadvantage that the vertical resolution is further reduced. Furthermore, 1) K has the problem that image quality deteriorates due to band limitations.

By the way, in the case of black-and-white television, it is possible to compress the band by horizontal interlaced scanning. In this horizontal interlaced scanning, the image signal is synchronized between the sending side and the receiving side and sampled using a round sampling signal), and the phase of this sampling signal is adjusted every frame (in the case of sequential scanning, the field period = 7 frame periods). 2w/N (interlace ratio of N horizontal interlaced scanning, N:1 interlace) is changed, and 1 of horizontal interlaced scanning is changed in N frames.
This completes the frame and compresses the transmission band by 17NK.

However, in the case of a composite signal such as a color television signal O, the appearance is slightly different from the above-mentioned black and white television signal.

That is, 1) When a composite signal (NTSC) is sampled too much, the color satcarrier fes returns to the low frequency range of the video signal, causing color tod disturbance (color satcarrier fes).
2) Luminance signal before NTBCK conversion on the sending side.

When sampling the chromaticity signal (y, c) separately, separating it into Y and C from NTBC on the receiving side, and then sampling and reproducing Y and C, the bandwidths of Y and C are the same. If so, it would be possible to sample with the same sampling signal, but since the bandwidths usually differ, it would be difficult to reproduce the butterfly chromaticity signal with the same sampling signal.

Therefore, the usage of horizontal interlaced scanning for color television W signals is a) band compression of only the luminance signal, and compression of the chromaticity signal (t).
(without changing the carrier frequency) and 'NT8CK conversion.

B) Convert the luminance signal and chromaticity signal to NTBC by compressing the band and triplexing the color, nap, and middle frequency signals.

(1) In (b), the color, sash, and carrier frequencies are also lowered to compress the entire band.

03 types of uses are possible. However, since the sash and carrier frequency change for R) K, the current TV set,
There is no convergence with online broadcasting. Therefore, we have to think of ways to use it in completely new fields. Furthermore, although methods a) and b) have the same conductivity as the conventional method, the transmission band of the composite signal as a whole is not reduced.

However, color dot interference can be improved by band separation of one luminance and one chromaticity, and resolution can be increased by transmitting to a higher frequency range than the current television signal.

Purpose of the Invention The present invention has been made based on the above circumstances, and its purpose is to enable transmission of luminance signals and chromaticity signals within a predetermined transmission band by separating the bands, without causing color dot interference. The present invention aims to provide a color television signal transmission device that can improve image quality.

SUMMARY OF THE INVENTION The present invention is characterized in that a luminance signal and a chromaticity signal are sampled on the transmitting side using sampling signals of different frequencies and then transmitted as an NT8C signal, and that the receiving side samples the luminance signal and the chromaticity signal using a sampling signal synchronized with the sampling signal on the transmitting side. It reproduces chromaticity signals.

Embodiment of the Invention Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows the configuration of the sending device, which has a conventional configuration with a sampling circuit added. Photographer tube 77
R, G, output from 1 +Ji@HljB,
The B color signal is supplied to a matrix circuit 11, and this matrix circuit 12 outputs a brightness variation signal ICY, a wideband chromaticity signal, and a narrowband chromaticity signal E. This luminance signal E1 corresponds to the luminance state of the pixel shown by KPY in FIG. . These luminance signal EY and chromaticity signal EG are the sampling circuit 1
1*e 131 113g each.

A luminance signal sampling signal 1719 KY2 is supplied to the sampling circuit 131 of the sampling circuit 11. ．． 13. JIC is sampling signal g for chromaticity signal
c1 m g□ is supplied.

Here, subscript 1 indicates a sampling signal for odd frames, and subscript 2 indicates a sampling signal for even frames, and the odd and even signals are shifted in phase by 180 degrees. These sampling signals are 11 gY2 e gcl
#get is the output signal of the synchronization signal generator 14 (horizontal,
11 serial synchronization signal) is generated in a sampling signal generator 15 supplied with the signal. In this generator 15, the sampling signals gY1 to gc! have the following relationship. is generated.

That is, here, the band Cmax of the chromaticity signal is simply set to 1/3 of the luminance signal Ymax (for example, Ymax M 5 M
For Hg, Cmax = 1.67 MHs), the frequency of the signal g that samples the chromaticity signal is 1/of the frequency of the signal 11 that samples the luminance C(t) signal.
Must be 3. This is because when the differential frequency ω is selected as YmaxK as shown in Fig. 4(a), the lower side band of the sampling becomes the low-pass filter characteristic (pass band 0 = Cmax/2), so
Figure (c) As shown in K, the Cmax/ of the chromaticity signal is
The component of Cmax is removed. Therefore, the same figure (d
) K As shown, the receiving side is y! In the case of a cylinder, the same figure (・
)K, the chromaticity signal cannot be reproduced.

In other words, in this compression method, the high-frequency components (ω, /2 to ω1) of the original signal are transmitted as lower band waves of ω by the spring ring on the sending side, and the original signal is reduced to 4 by sampling on the receiving side. Rounding is based on the principle of signal band, and in many cases there is no compression effect at all.

In other words, the maximum compression effect can be expected when the signal band is #-, and the compression effect can be expected at ωS<signal band T, but the transmission line band is 61. /2 was decided. Therefore, the sampling frequency ω cannot be chosen arbitrarily, but is twice the transmission band (in the case of N-2).
The maximum effect is obtained when (signal band) - ω, = 2 x (transmission band).

The nine luminance signals and chromaticity signals sampled by the above sun cylinder signal are each filtered through a low pass filter (LP).
F ) 1 # * e I II fable e 1 g
B, and the required signal is extracted. This 16-fold filter has 1 sampling signal #1 of gyz frequency
The filter 161 has a passband of /2 or more (excluding the differential frequency 19f).

161 is the sampling signal gc, ? get frequency 1
, / 2. It has the above passband (excluding the differential 19ff frequency). The output signal E of this filter lit is
la, are supplied to the adder 11, and fikp16. ,16
．． (D output signal Fi, NT8Cx y = y - da 18
supplied to Output signal of this encoder 18 -1'
"C2 is supplied to the adder 11. This adder 11
includes the output signal of the synchronizing signal generator 14 and the oscillator 1.
A color burst signal generated by the burst generator 20 is supplied from the 3, 58 Wnls signals outputted from P. The composite signal output from this adder ZF is modulated W
After being modulated by kll, it is sent out through the antenna 22.

On the other hand, FIG. 2 shows the configuration of the receiving device. In this case as well, a sampling circuit is added to the conventional configuration like the sending device. That is, the signal received in the air @XS is sent to the detector j! via a high frequency amplifier (not shown) or the like. 41f
C is supplied. Of this detected output signal, the luminance component is supplied to the sampling circuit 11HIIC, and the chromaticity component is supplied to the chrominance signal demodulator srK via the band amplifier 1#.

The extracted nine-color burst signal (i9, the above-mentioned detection output signal) is extracted by a burst amplifier "l, and an is8MHs oscillator Xj.
The chrominance signal demodulator JFK is supplied through the chrominance signal demodulator JFK. The broadband chromaticity component and the narrowband chromaticity component output from the demodulator jr are respectively supplied to a sampling circuit 11 ellaK.

Jin's Nanfψnda Circuit 21 Yuki ell Hatake and zi, r
lc is the sending side and the nine ringing signals 'ltgH
sgi Ij2 e gy, I gyt is supplied and stone. These sampling signals gel to gel are generated by a sampling signal generator 1aKk. That is, the detection output signal, for example, a horizontal synchronizing signal, is supplied to the synchronizing signal generator J#, and this horizontal synchronizing signal is used to generate sampling signals gyt~ with different frequencies and phases using well-known means such as a PLL circuit. A smell is generated. The Kukihen signal ET is sampled by this sampler signal.

Broadband, narrowband chromaticity signals 1. t IIQ are each supplied to the matrix circuit si<, and this matrix circuit 31
At fC, the sending side) is sent 9R,G.

The B color signal is reproduced. This R+G IB color signal is supplied from a cathode ray tube JJK (Fig. 3Kg).

j) Displayed in a pleading manner. In FIG. 3, the transmission waveform (subcarrier modulation line) of the chromaticity signal "ct'" ct indicates the baseband state. In reality, the chromaticity signal is balanced modulated and placed on the nap carrier, but it is shown as follows. Oku, *) and J) are actually displayed as Nezumi, G and BK decoded, but for the same reason they are displayed as Y.

11 of C is shown. That is, 1) shows the cathode ray tube display of the luminance signal, j) shows the cathode ray tube display of the chromaticity signal, and the double frames are even numbered 7 frames, and the others are odd numbered 1.1° frames.

According to the above configuration, since the luminance signal and the chromaticity signal are each sampled and transmitted, FIG.
As shown, the luminance signal EY and the chromaticity signal Ect can be transmitted separately. Therefore, since there is no chromaticity signal in the luminance signal band as in the conventional NTSC system shown in FIG. Furthermore, since the signal is compressed and transmitted, a sufficient luminance signal band can be obtained. Therefore, it is possible to increase the resolution of the image.

Effects of the Invention As detailed above, according to the present invention, the luminance signal and color signal can be band-separated and transmitted within a predetermined transmission band, and the image quality can be improved without causing color tod disturbance. Yong signal transmission equipment can be provided.

[Brief explanation of the drawing]

1 and 2 show an embodiment of a color television signal transmission device according to the present invention. FIG. 1 shows the configuration of the transmitting device, and FIG. 2 shows the configuration of the receiving device. diagram showing,
Figure 3 is the same as Figure 1. Figure 4 (a) to (•) are diagrams shown to explain the frequency of the sampling signal, and Figure 5 (a) is a diagram showing the signals of each part to explain the operation of Figure 2. A diagram showing the spectrum of a color television signal according to
b) is a diagram showing a conventional power 2-television signal 3° ET...luminance signal; EC...chromaticity signal; ...Color signal demodulator, 12゜31...Matrix circuit. Applicant's agent Patent attorney Takehiko Suzue Figure 3 J Mouth=ko Misumi=ko

Claims (1)

[Claims] Means for generating a sampling signal for a 11 degree signal and a sampling signal for a chromaticity signal having a lower frequency than this sampling signal, and R, G, B. A luminance signal and a chromaticity signal generated in the same manner as the chrominance signal are supplied, means for sampling these signals with the corresponding sampling signal, and a means for performing predetermined band limiting on the sampling output signal, synthesizing it, and sending it out as a composite signal. a transmitting device comprising a means for detecting a received signal, a means for demodulating a chromaticity signal component from the detected output signal, and a transmitting device that synchronizes with the sampling signal of the transmitting device. means for generating a ring signal; means for sampling nine luminance signal components and said chromaticity signal components extracted from said detection output signal using said sampling signal to generate four luminance signals and four chromaticity signals; and said luminance signal. and a receiving device comprising means for reproducing R, G, and B color signals from the chromaticity signals.