JPS63308493A - high definition television system - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a high-definition television system that achieves high image quality of television.

[Conventional technology]

There is a growing movement towards higher quality televisions.

The NTSC system, which was established more than 30 years ago, brought about the prosperity of today's television through the multi-processing of color signals, but as receivers have improved in performance and become larger, their shortcomings have become more apparent. It's starting to look like this. Therefore, while research is being conducted in various places to try to overcome these shortcomings using signal processing technology and devices that have rapidly developed in recent years, attempts are also being made to take the image quality one step further.

Broadly speaking, methods for improving image quality can be categorized as, for example, the Journal of the Television Society, Von, 39. No. 10 (fM85)
pp, 885-897 and the same <Voi', 40.
No. 5 (fM86) pp, 357-365
As described in , IDT V handles television signals as three-dimensional signals, leaves the current NTSC system unchanged, and performs mainly signal processing on the receiving side.
(Improved TV) and the current NTSC system while modifying the signal format and adding new signals.
ition TV). In EDTV, high-definition information, such as a horizontal high-frequency luminance signal Y of 4.2 MHz or higher, is used as a carrier wave μ. F U CE (Fully Compatible
EDTV) has been studied most vigorously and is attracting attention (for example, fM 13-14, Proceedings of the 1986 National Conference of the Society of Television Engineers, pp. 333-334).

[Problem that the invention seeks to solve]

Now, if we look at the carrier wave that is in a frequency interleaved relationship with the luminance signal, this carrier wave is reversed by 180 degrees for each scanning line and for each frame, so the time axis T and the axis in the vertical scanning direction (vertical scanning axis) The phase of the carrier wave in each field and each scanning line on a plane consisting of the following is as shown in FIG. 6 or 7. In the same figure, each circle represents a scanning line, and the arrow within each circle represents the phase of the carrier wave. If the row of circles in the direction of the vertical scanning axis ■ is the scanning line in the same field, and the circle surrounding the upward arrow is the scanning line of the carrier wave whose phase is θ, then the circle surrounding the downward arrow is the scanning line of the carrier wave whose phase is θ. This is a scanning line of a carrier wave at (θ+180°).

In the case of FIG. 6, the scanning lines of carrier waves of the same phase are displaced upward on the V-T plane with time, as shown by arrow A, and in the case of FIG. 7, as shown by arrow B, , displaces downward with time.

On the other hand, as described in the above-mentioned literature, a television signal can be handled as a three-dimensional signal in a three-dimensional frequency space defined by a time frequency fA, a horizontal frequency fH1, and a vertical frequency fv.

On a plane defined by the time-frequency axis f7 and the vertical frequency axis fv of such a three-dimensional frequency space (ft-fv plane, the same applies hereinafter), the carrier wave represented by FIG. 6 is as shown as a point in FIG. 8, The carrier waves present in the second and fourth quadrants and represented by FIG. 7 are present in the first and third quadrants, as shown as dots in FIG. 9.

Therefore, when such a carrier wave is modulated with a desired signal, the resulting modulated signal is represented by a solid line frame in FIG. 8 or 9. Here, FIGS. 8 and 9
In the figure, the vertical frequency axis fv force direction range of these signals represents a vertical frequency band, and the wider this band, the higher the vertical resolution. This means that the horizontal frequency axis fH corresponds to a frequency axis representing a normal signal frequency spectrum, and the wider the frequency band (horizontal frequency band) represented by this, the higher the horizontal resolution.

By the way, in the above-described FUCE, the subcarrier fSC of the color difference signal C has the phase shown in FIG. has the phase shown in FIG. 7, with subcarrier fSC and carrier μ. Toga fT-
They are made to exist in different quadrants of the fv plane. As a result, as shown in FIG. 10, in the fv-f plane, if the solid line frame is the horizontal luminance signal Y, the broken line frame is the color difference signal C.

=4- Therefore, there is no problem since YH and C, which are on opposite sides of the vertical frequency axis fv, do not overlap, but the carrier wave μ. is 0.6fSC, the horizontal high-frequency luminance signal Y,
There is a part where the horizontal frequency band of the color signal C and the horizontal frequency band of the color signal C are opposed to each other with respect to the horizontal frequency axis f++ (the axis perpendicular to the paper surface of FIG. 10), and in this part, the horizontal frequency band of the color signal C is
In the figure, the vertical frequency bands of the horizontal high-band luminance signal YH and the color difference signal C overlap on both sides of the vertical frequency axis fv. Therefore, in order to increase the vertical resolution of the horizontal high-band luminance signal Y and achieve high image quality, it is necessary to limit the vertical frequency band of the color difference signal C, as shown in FIG.
For this reason, there was a problem in that the vertical resolution of the color difference signal C deteriorated.

Furthermore, in Fig. 10, when trying to increase the vertical resolution of the color difference signal C, the vertical frequency band of the horizontal high-frequency luminance signal Y□ must be limited, as shown in Fig. 12, as in the previous case. Therefore, the vertical resolution decreases, making it impossible to achieve high image quality.

Considering the above points, horizontal high-frequency luminance signal YH and color difference signal C are
However, in any case, these vertical frequency bands are limited and the vertical resolution cannot be sufficiently increased.

Note that in this conventional HDTV, the multiplexing forms of the horizontal high-range luminance signal YH and the color difference signal C are fH and fv.

When shown in the three-dimensional frequency space of fl, it becomes as shown in FIG. In the figure, a horizontal high-frequency luminance signal Y. and color difference signal C
are arranged in the vertical frequency axis fv force direction, which limits the vertical frequency band of the color difference signal C and lowers the vertical resolution.

In this prior art, in the case of video, the field.

Since the information content of the television signal changes for each frame, the time-frequency axis fT and the force direction frequency band of the horizontal high-frequency luminance signal YH1 and color difference signal C change, so the horizontal high-frequency band on one side of the vertical frequency axis f changes. The luminance signal Y, 1 and the color difference signal C on the other side partially overlap. Therefore, the color difference signal C
is the horizontal high-frequency luminance signal Y. It is necessary to remove the horizontal high-frequency luminance signal Yl+ in order to prevent it from being disturbed by the horizontal high-frequency luminance signal Yl+.

Therefore, with the conventional technology, the horizontal height signal YH cannot be reproduced for moving images, and the resolution cannot be increased.

As shown in FIG. 14, the vertical frequency bands of the horizontal high-frequency luminance signal Y□ and the color difference signal C are arranged in the direction of the vertical frequency axis fv, and the horizontal high-frequency luminance signal YH is the first .
When the color difference signal C is present in the second and fourth quadrants in the third quadrant, it is necessary to use an expensive field memory to separate the horizontal high-frequency luminance signal Y)I and the color difference signal C. A three-dimensional filter is required, and also a carrier μ. is 0.6f
Since it is an SC, modulation/demodulation and carrier wave μ are caused by this. However, since the horizontal high-frequency luminance signal YH is shifted to the low frequency range while maintaining the high-low frequency relationship, a portion of its high energy is placed on the low frequency side, which may interfere with the current television system. There is a problem with being conspicuous.

It is an object of the present invention to solve such problems, to increase the resolution of color difference signals and horizontal high-frequency luminance signals, and to increase the resolution of moving images, and to easily separate horizontal high-frequency luminance signals and color difference signals using simple means. An object of the present invention is to provide a high-definition television system that can reduce interference with existing televisions.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a subcarrier frequency twice the subcarrier frequency of the color difference signal multiplexed on the luminance signal,
The horizontal high-frequency luminance signal is converted to low-frequency signals using a pulsed carrier wave whose phase is inverted for each scanning line and frame.
The baseband width of the color difference signal is set to be equal to or less than the difference between the highest frequency of the multiplexed brightness signal and the subcarrier frequency of the color difference signal.

[For production]

In FIG. 5(a), the frequency band of the horizontal high-frequency luminance signals Y and I (this is f, fv-f, in the three-dimensional space,
The horizontal frequency band) is 4.2 to 6.2 MHz,
When the subcarrier frequency f3C of the color difference signal C is 3.58 MHz, the carrier wave μ converts the horizontal high band luminance signal YH to a low band.

The frequency of is 7.16MHz.

This carrier wave μ. When the horizontal high-frequency luminance signal Y)l is converted to a lower frequency band, the component of these differences becomes a negative frequency band, as shown by the broken line in Fig. 5(b), but this is reversed with respect to the zero frequency axis. , a horizontal high-band luminance signal YH in a frequency band as shown by the solid line is obtained.

On the other hand, FIG. 5(c) shows a television signal of the current NTSC system, in which a color difference signal C with a subcarrier frequency f sc (=3.58 MHz) is multiplexed on a luminance signal Y with a maximum frequency of 4.2 MHz. There is. The baseband width of this color difference signal C is 4.2-3.58=0.6 MHz or less (here, 0.5 MHz), and therefore the frequency band of the color difference signal C is 3.1-4. It is 1MHz.

Therefore, if the horizontal high-frequency luminance signal Yl (shown in FIG. 5(b)) is multiplexed onto this NTSC television signal,
As shown in FIG. 5(d), the horizontal high-frequency luminance signal Y and the color difference signal C are completely separated in the horizontal frequency axis fH force direction.

In this case, the horizontal high-frequency luminance signal Y4. An ordinary horizontal filter can be used to separate the color difference signal C and the color difference signal C, and a three-dimensional filter using a field memory is not necessary.

Carrier wave μ. may have the phase change shown in FIG. 6, or may have the phase change shown in FIG. Carrier wave μ. When the phase changes as shown in FIG.
In the arfv plane, it becomes as shown in Fig. 8, and the carrier wave μ. is the seventh
When the phase changes as shown in the figure, the horizontal high-frequency luminance signal Y
It will look like the figure. Here, the phase of the subcarrier of the color difference signal C changes as shown in FIG. 6, and the phase of the subcarrier wave of the color difference signal C changes as shown in FIG. Assuming that the phase of
, the multiplex form is as shown in FIG.

As is clear from the figure, the color difference signal C and the horizontal high-band luminance signal Y are arranged in the direction of the water frequency axis fH, and one of these vertical frequency bands does not limit the other. Therefore, the color difference signal C and the horizontal high-frequency luminance signal Y
The vertical resolution of H can be increased in both cases.

Moreover, as explained in FIG. 5, the color difference signal C is band-limited. Then, when the horizontal high frequency luminance signal YH is converted to a low frequency band, it is inverted so that its highest frequency is on the low frequency side and its lowest frequency is on the high frequency side, as explained in FIG. 5(b). NTSC television signal (Figure 5 (C))
multiplexed into

In this case, the lowest frequency of the horizontal high-band luminance signal YH is constant (here, it is 4.2 MHz, which is converted to a low frequency by the carrier wave μ. to 3 MHz). This lowest frequency is the carrier wave μ. When the frequency band is low-band converted by , the frequency band is lower than the frequency band of the color difference signal C, as shown in FIG. 5(d). Furthermore, in the case of a moving image, the frequency band of the horizontal high-band luminance signal YM changes (the frequency band of the color difference signal C is limited), but this is because the highest frequency changes. Therefore, the fifth
In figure (d), in the case of a moving image, the horizontal high-frequency luminance signal Y
The frequency band of , expands and contracts to the lower side, and this and the frequency band of the color difference signal C do not overlap.

From the above, even in the case of moving images, the horizontal high-frequency luminance signal YH can be multiplexed onto the NTSC television signal. Moreover, since the lowest frequency component with large energy of the horizontal high-frequency luminance signal YH is located on the high-frequency side of the luminance signal Y (near 3 MHz of the color difference signal C), the television signal shown in FIG. Even when the image is received by a receiver using this method, there is very little interference caused by this horizontal high-frequency luminance signal YM.

Also, the carrier wave μ. Since the frequency of is twice the subcarrier frequency fSC, the modulation/demodulation of the horizontal high-frequency luminance signal Y and the carrier wave μ. Phase regeneration becomes extremely easy.

Note that most of the current system home television receivers have a color reproduction band of 0.5 MHz, so in the present invention, the frequency band of the color difference signal C is set to 0.5 MHz.
Even if the frequency is limited to MHz, the image quality will not deteriorate.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing an encoder of a first embodiment of a high-definition television system according to the present invention,
~3 are input terminals, 4~6 are A/D (analog/digital) converters, 7 is an RGB/YUV conversion circuit, 8 is an interlace interference detector, 9~11 are interlace interference removal circuits, 12~14 are N /I (non-interlace/interlace) conversion circuit, 15 is a crosstalk detection circuit, 16 to fM are crosstalk removal circuits, 20 is LPF
(low pass filter), 21 is HPF (bypass filter), 22 to 24 are LPF, 25 is color difference signal modulation circuit, 26 is multiplication circuit, 27 is addition circuit, 28 is synchronization signal addition circuit, 29 is D/A (digital/analog) converter, 30 is an output terminal, 31 and 32 are input terminals, 33 is a synchronization signal generation circuit, and 34 is a carrier wave generation circuit.

This embodiment is an encoder that converts an RGB signal with a 525/60 non-interlaced scanning line structure into a high-definition television signal by performing adaptive interlace conversion and adaptive YCYH frequency multiplexing.

A -- In FIG. 1, non-interlaced R and G.

The B signals are input from input terminals 1, 2.3, respectively, and the A/D
Converter 4. ．． After being converted into a digital signal in 5.6,
The signal is supplied to an RGB/YUV conversion circuit 7 to generate a luminance signal Y and color difference signals U and V.

In the case of moving images, when these non-interlaced signals are converted into interlaced signals, aliasing distortion occurs, which causes interference. Interlace interference detection path 8 receives luminance signal Y
The frequency characteristics of the interlace interference removal circuits 9, 10, and 11 are detected to detect the absence of components that cause aliasing components that become interference. When this is detected, the interlace interference removal circuits 9, 10, and 11 remove the luminance signal Y, the color difference signal U, and The frequency band of V is limited to remove components that cause aliasing distortion. In the case of still images, such interference components do not occur in non-interlace/interlace conversion, and the bands of each signal are not limited. This prevents a decrease in vertical resolution. In this way, the interlace interference detection circuit 8 and the interlace interference removal circuit 9.10.11
Accordingly, the luminance signal Y and color difference signals U and V are subjected to adaptive processing according to the characteristics of the signals.

The luminance signal Y and color difference signal U that have been adaptively processed in this way
, V are supplied to N/I conversion circuits 12, 13, and 14, respectively, and every other scanning line is thinned out to become an interlaced signal.

The crosstalk detection circuit 15 examines the frequency characteristics of the luminance signal Y, and outputs a luminance signal Y1, a color difference signal C1, a horizontal high-frequency luminance signal Y8
Based on the control signal from the detection result of the crosstalk detection circuit 15, the crosstalk removal circuits 16 and 17 detect the presence or absence of a crosstalk component when multiplexing the luminance signal Y.
, the crosstalk removal circuit 18. fM is the color difference signal U
, V adaptively bandlimits. The luminance signal Y from the crosstalk removal circuit 16 has its horizontal frequency band limited to 4.2 MHz or less by the LPF 20 to become a low-band luminance signal YL, and the luminance signal Y from the crosstalk removal circuit 17 is passed through the HPF 21. The horizontal frequency band is limited to 4.2 to 6.2 MHz by the LPF 24, and the horizontal high frequency luminance signal y shown in FIG. 5(a) is generated. This horizontal high-frequency luminance signal Y)I is multiplied by the carrier wave generation circuit 26 and
The carrier wave μ from 4. By calculating the multiplier and the multiplier, a low-frequency conversion is performed as explained in FIG. 5(b).

Further, the horizontal frequency bands of the color difference signals U and V from the crosstalk removal circuit 18.1.9 are each limited to 0.5 MHz or less by the LPF22.23, and are supplied to the color difference signal modulation circuit 25 to generate a synchronization signal. Orthogonal modulation is performed using the subcarrier fSC from the circuit 33, and a color difference signal C is generated.

In this case, the carrier wave μ. The frequency of is set to twice the subcarrier frequency fSC.

The low-range luminance Y from the LPF 20, . After the synchronization signal from the generation circuit 33 is added and a burst signal is formed from the subcarrier rsc and added, the D/A converter 29 generates the burst signal as shown in FIG.
The signal is converted into an analog high-definition television signal shown in d) and output from the output terminal 30.

The synchronization signal generation circuit 33 receives input from the input terminal 3L 32.
17= Horizontal drive signal HD to be input, subcarrier fSC from vertical drive signal VD, horizontal and vertical synchronization signals, pulse HAL that is inverted every scanning line, pulse VAL that is inverted every frame, 2
A signal of frequency fSC is generated.

The carrier wave generation circuit 34 generates a signal with a frequency of 2f from the pulses HAL, VAL and a signal with a frequency of 2fSC. for each scan line,
A pulsed carrier wave μ that is reversed by 180° every frame. generate.

FIG. 2 is a block diagram showing a decoder according to the first embodiment of the present invention, in which 35 is an input terminal, 36 is an A/D converter,
37 is a motion detection circuit, and 38 is an adaptive Y-CY.

Separation circuit, 39 is LPF, 40 is multiplication circuit, 41 is L
PF, 42 is HPF, 43 is addition circuit, 44 is color difference signal demodulation circuit, 45.46 is LPF, 47 is motion detection circuit,
48, 49.50 is the scanning line interpolation circuit, 5L 52.53
is an I/N (interlace/non-interlace> variable m circuit, 54 is a YUV/RGB conversion circuit, 55.56.
57 is a D/A converter, 58.59.60 is an output terminal, 6
1 is a synchronization separation circuit, 62 is a synchronization signal generation circuit, 63 is a carrier wave generation circuit, and 64 and 65 are output terminals.

This decoder converts high-definition television signals into adaptive Y
By performing CYo separation and adaptive non-interlace conversion, it is converted into a 525/60 interlace RGB signal.

In the same figure, a high-definition television signal input from an input terminal 35 is converted into a digital signal by an A/D converter 36, and is sent to a motion detection circuit 37, an adaptive Y-CY, a separation circuit 38, and a sync separation circuit 61. and will be supplied. The adaptive Y-CYu separation circuit 38 switches between inter-frame calculation and inter-line calculation based on the motion information from the motion detection circuit 37, and generates a composite signal of the low-range luminance signal YL, the color difference signal C, and the horizontal high-range luminance signal YII. Separate into two parts. Low range luminance YL is LP
F39 limits the frequency band to 4.2 MHz. In the arithmetic circuit 40, the multiplication is the carrier wave μ. is multiplied by the composite signal of the color difference signal C and the horizontal high-frequency luminance signal Y□, thereby performing high-frequency conversion so that the horizontal high-frequency luminance signal YH has the original frequency band. The high-frequency converted composite signal is L
With PF41 and HPF42, the frequency band is 4.2 to 6.
．． The frequency is limited to 2 MHz, and the horizontal high frequency luminance signal YH is separated. The low-frequency luminance YL from the LPF 39 and the horizontal high-frequency luminance signal YM from the HPF 42 are added in an adder circuit 43.
A broadband (0 to 6.2 MHz) luminance signal Y is obtained.

On the other hand, the composite signal of the color difference signal C and the horizontal high-frequency luminance signal YH output from the adaptive Y-CYH separation circuit 38 is supplied to the color difference signal demodulation circuit 44 and demodulated with the subcarrier f3C from the synchronization signal generation circuit 62. Ru. This color difference signal demodulation circuit 4
One output signal of 4 is band-limited to 0.5MHz by LPF45 to obtain color difference signal U, and the other output signal is LP
The band is limited to 0.5 MHz at F46, and a color difference signal V is obtained.

The luminance signal Y from the adder circuit 43 is supplied to a motion detection circuit 47 and a scanning line interpolation circuit 48, and is supplied as a color difference signal U.

(2) are supplied to scanning line interpolation circuits 49 and 50, respectively.

The motion detection circuit 47 detects motion information from the luminance signal, and based on this, the scanning line interpolation circuits 48, 49, and 50 perform interframe interpolation and interline interpolation on the luminance signal Y and color difference signals U and V. is switched to create an interpolated scanning line, which is output together with the main scanning line. I/N conversion circuit 51.52.5
3 is the output signal of the scanning line interpolation circuit 48, 49, 50.
The signal is converted into a 25/60 non-interlaced luminance signal Y and color difference signals U and V, which are supplied to a yuv/RGB conversion circuit 54 and converted into R, G, and B signals. These R, G, and B signals are processed by D/A converters 55, 56, and 57, respectively.
is converted into an analog signal by the output terminal 58. Zui,
60.

On the other hand, the synchronization information and carrier wave information separated from the high-definition television signal by the synchronization separation circuit 61 are supplied to the synchronization signal generation circuit 62. The synchronization signal generation circuit 62 generates a pulse HAL that is inverted for each line, a pulse VAL that is inverted for each frame, a subcarrier rsc, and a pulse having twice the frequency of the subcarrier rsc, and the subcarrier rsc is sent to the color difference signal demodulation circuit 44. At the same time, the horizontal drive signal HD and vertical drive signal VD are outputted to the outside through output terminals 64 and 65. The carrier wave generation circuit 63 generates pulses HAL, VAL and 2
Carrier wave μ based on fSC pulse. is formed and supplied to the multiplication circuit 40.

FIG. 3 is a block diagram showing an encoder of a second embodiment of the high-definition television system according to the present invention, and parts corresponding to those in FIG. 1 are given the same reference numerals.

This example is 525/30 interlaced R.

The G and B signals are converted into high-definition television signals by performing adaptive YCY□ frequency multiplexing. Here, R, G,
Since the B signal is interlaced and the high-definition television signal outputted from the output terminal 30 is also interlaced, non-interlace/interlace conversion is unnecessary. Therefore, the encoder of FIG. The only difference is that interlace interference removal circuits 9 to 11 and N/I conversion circuits 12 to 14 are not provided.

FIG. 4 is a block diagram showing the decoder of this second embodiment, and parts corresponding to those in FIG. 2 are given the same reference numerals.

This embodiment converts high-definition television signals into adaptive YCY
□By performing separation, it is converted into 525/30 interlaced R, G, and B signals. here,
An interlaced high-definition television signal is input to the input terminal 35, and similarly interlaced R, G, and B signals are output to the output terminals 58-60. For this,
Adaptive interlace/non-interlace conversion is not required, and therefore the decoder shown in FIG. 2 differs from the one shown in FIG.
The only point is that there is no need to provide the /N conversion circuits 51 to 53.

On the transmitting side, the encoder shown in FIG. 1 or 3 encodes the R, G, and B signals into a high-definition television signal, and the signal is transmitted to the receiving side via the transmission path of the current NTSC system. On the receiving side, the high-definition television signal is converted into R, G, and B by the decoder shown in Figure 2 or Figure 4.
decode into a signal.

By combining the sender and receiver in this way,
These embodiments have the following effects.

That is, the vertical resolution of the color difference signal C is twice that of the conventional EDT (2). The vertical resolution of the high-band luminance signal YH is doubled compared to conventional EDTV. Since YH can be played even in the case of video, the video resolution is improved compared to conventional EDTV. The decoder uses a color difference signal C and a horizontal high-frequency luminance signal Y.
No field memory is required to separate the ll and ll. Modulation/demodulation of horizontal high-frequency luminance signal YH and carrier wave μ.

phase regeneration becomes much easier than in conventional EDTV. Interference with the current television system is smaller than that of conventional EDT■.

〔Effect of the invention〕

As explained above, according to the present invention, since the vertical frequency band and the horizontal frequency band of the horizontal high-frequency luminance signal YH and the color difference signal C do not overlap with each other, the color-difference signal C2 and the horizontal high-frequency luminance signal YH It is possible to widen the vertical frequency band sufficiently to increase the vertical resolution, and to separate them, a normal filter can be used, eliminating the need for a three-dimensional spatial filter using field memory. Also in the case of horizontal high-frequency luminance signal -23
= Even if the horizontal frequency band of the signal Yll changes, it does not overlap with the horizontal frequency band of the color difference signal C, making it possible to multiplex transmission and playback of the horizontal high-frequency luminance signal YH. Resolution improves.

Further, modulation/demodulation of the horizontal high-frequency luminance signal Yl+ and its carrier wave μ. phase reproduction is much easier than in conventional EDTV, and since the horizontal high-frequency luminance signal Y is frequency-inverted and multiplexed, the component with large energy becomes the high-frequency side of the luminance signal. Compared to conventional EDTV, interference with current television systems can be reduced.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an encoder of a first embodiment of a high-definition television system according to the present invention, FIG. 2 is a block diagram also showing a decoder, and FIG. 3 is a block diagram showing a first embodiment of a high-definition television system according to the present invention. FIG. 4 is a block diagram showing the encoder of the second embodiment, FIG. 4 is a block diagram showing the decoder as well, FIG. 5 is an explanatory diagram showing the operating principle of the present invention, and FIGS. 6 and 7 are diagrams of carrier waves and subcarriers, respectively. Schematic diagrams showing the scanning line structure related to phase; Figures 8 and 9 are characteristic diagrams of color difference signals and horizontal high-frequency luminance signals in the three-dimensional frequency space on the time-frequency axis-vertical frequency axis plane; Figures 10-
Fig. 13 is a characteristic diagram on the time-frequency axis-vertical frequency axis plane in a three-dimensional frequency space showing the relationship between the vertical frequency bands of the multiplexed color difference signal and the horizontal high-frequency luminance signal, and Fig. 14 is a three-dimensional frequency space FIG. 15 is a three-dimensional frequency characteristic diagram showing the frequency relationship between the multiplexed color difference signal and the horizontal high-frequency luminance signal of the conventional EDTV, and FIG. FIG. 3 is a three-dimensional frequency characteristic diagram showing the frequency relationship of FIG. 1.2.3...R, G, B signal input terminal, 7...
RGB/YUV conversion circuit, 20...LPF, 21...
・HP F. 22, 23...LPF, 24...LPF, 25
... Color difference signal modulation circuit, 26 ... Multiplying circuit is arithmetic circuit, 27
...Addition circuit, 30...Output terminal for high definition television signal, 34...Carrier wave generation circuit, 35...Input terminal for high definition television signal, 38...Adaptive Y-
CYH separation circuit, 39...I-P F, 40=26-...Multiple is arithmetic circuit, 41...LPF, 42...HP
F, 43...Addition circuit, 44...Color difference signal demodulation circuit, 54...Y U V/RGB conversion circuit, 58.59
．． 60...R, G, B signal output terminal, 61...
Synchronous signal separation circuit, 63...carrier wave generation circuit. ward -27 = Figure 5 (dou (MHz)) 6th ffl 78th - fv fvt
Figure 1I Figure 12 1sf311 14th II

Claims (1)

[Claims] 1. Band-limit the luminance signal to the highest frequency f_M to make it a low-band luminance signal, and set the frequency f_S_C (however, f_S_C<f
A color difference signal amplitude-modulated with a subcarrier of __M) is frequency-multiplexed on the low-band luminance signal to produce a television signal, and a horizontal high-band luminance signal consisting of a component of frequency f_M or higher of the luminance signal is frequency-multiplexed and transmitted. In a high-definition television system, a first means for generating a carrier wave having a frequency twice the frequency f_S_C of the subcarrier wave and having a phase inverted for each scanning line and each frame; means for converting the signal to a low frequency band, the baseband width of the color difference signal is set to (f_M-f_S_C) or less, and the horizontal high frequency luminance signal is converted to the television signal in a frequency band lower than the frequency band of the color difference signal. A high-definition television system characterized by frequency multiplexing.