JPS59143488A - Method of generating base band video signal of high resolution - 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 TECHNICAL FIELD The present invention relates to a system for providing improved television picture quality, and in particular to a system for providing an improved quality signal for specially designed receivers, and for providing improved television picture quality over conventional receivers. It relates to a system that provides a signal of normal quality without modification to the receiver.

BACKGROUND OF THE INVENTION It has long been desirable to provide high definition television images that approximate the quality of projection film images.

For example, Ottopa H. of the R.C.N.
"Comparison of photo and television systems" (Imape Qnal 1)
tyr”A Comparison of Photo
graphic and television 5y
stenrs”, 0tto Ha 5hade
, Tre.

RCA Corporation, 1975).

The first problem in achieving this goal remains unchanged.
The new system employs signals that can be received by fully compatible conventional television receivers, operating according to the NTSC, PAL, or SECAM standards, respectively, and requires an incredibly wide bandwidth! It must be able to transmit an enhanced signal to the newly designed receiver without any interference.

Prior art ideas that promised good image quality but required extremely wide bandwidths or were incompatible with existing receivers were disclosed and published by DG in February and March 1980.・High precision R by Fink
, The Future of l+1 Degree Television: SMPTE Research Group Report on High Definition Television, Part 1 ``'' SMPTE Journal Volume 89, Issue 2, Pages 89-94
Pages, and Volume 89, No. 3, Pages 153-1
61, and was further published by Takashi Fujio in August 1980 under the title ``Signal Standards and Transmission for High-Precision, One-List Television Systems,'' SMPTE Magazine Vol. 89, No. 8, 5.
Described on pages 79 to 584, 1'981 peak 3
It was published in September by Kozo Hayashi under the title ``Research and Development of High-Definition Television in Japan'' in SMPTE Journal Vol. 90, No. 3, pages 178-186. In these systems, the unit 1°02 per frame
'3 to 2125 scan lines, 20 to 50 MHz
of bandwidth.

Other technologies, referred to as high-definition or high-definition television systems, use methods such as increasing the aspect ratio, increasing the number of horizontal resolution lines, or better filtering the color subcarrier pattern to improve the filtering effect of conventional TV signals. This is a modified version of . U.S. Pat. It gives image quality. The low frequency part of the spectrum is transmitted during every image field, but
The midrange and high frequency parts are time-division multiplexed between the odd and one-out fields. U.S. Pat. No. 4,296,431, awarded to K. F. Holland on October 20, 19'81 describes The two color signal coordinates of the image signal are inverted. The chrominance subcarriers in adjacent frames are 1,800 degrees out of phase, and the chrominance subcarrier frequency is chosen to be twice the standard (NTSC) frequency to reduce horizontal sweep harmonic interference.

Other techniques for improving horizontal and vertical resolution as well as reducing low frequency flicker are described by B. Wendland in September 1980, NTC Fatzhaber (Germany), Vol. 7. Compatible high-definition-television system concept'' (B.

Wendland:'Concepts For A
CompatibleHIFI-Te1evisi
on Systemj ”NTG-Fachbe
r(Germany) Vol, 7. Septe
Mber, 1980hpp 407-416) and is shown on pages 407 to 416. In the receiver, double-speed image sampling, digital signal processing, and offset sampling are used in conjunction with pixel storage.

A useful summary of the techniques suggested is contained in the following paper presented at the SMPTE High Definition Television Conference held in October 1982 in Otsutawa, Canada. These include ``High Definition Television and its Alternatives'' by Sardine Child of the British Broadcasting Corporation, and Signal Processing for Compatible High Definition Television Systems (First Report) by Be Wendland of the University of Dortmund in West Germany. )", "Future Television System" by T. Nis Robson of IBA, "Compatible Alpha Points of Television by Kearns H. Powers of RCIA Research Institute" (JanChilds, BBC”
High Definition Te1evisio
and Its Alternatives”B,
Wendlan+LDortmund Univer
city+West Germany+”Signa
l Pr, easing for Compati
ble HDTV Systems, First Re
5ults+ T, S,' Robson.

I B, A a ”Te1evision System
ms For The Future, ”and K
erns H, Powers+ RCA Labor
Atories+”Corncompatibility A
"spects of HDTV").

Child's paper uses P to reduce cross-color effects.
This describes divided luminance coding for an AL system. Based on the 1977 World Radio Administration Conference (WARC) plan, which was designed to include the higher portion of the normal baseband luminance spectrum in an area separated from the band occupied by color information. The proposal makes use of the wide bandwidth available for satellite channels. The normal high frequency luminance signal is easily deviated from the normal signal by using the 4.4 MHz chrominance subcarrier in a PAL system. This particular excursion was chosen because the chrominance subcarrier is obtained at both encoder and decoder with precisely known phase, and the chrominance subcarrier has the lowest visibility in the decoded signal.

The reason why only one carrier wave is used is to allow for intermodulation in the satellite transponder as well.

However, the system is not fully compatible with existing PAL receivers, as the proposed system cannot be received by standard PAL receivers without the addition of a satellite PAL first stage. merely reduces the cross-color effect without attempting to increase the vertical and horizontal resolution.

SUMMARY OF THE INVENTION A high definition television image signal in accordance with the principles of the present invention comprises:
Legacy, unmodified (NTSC, PAL, respectively)
, or according to the SECAM standard) in a television set at normal resolution and configured to be received by a modified receiver that does not need to be wider than twice the bandwidth of the traditional broadcast channel. be.

In the illustrated embodiment, the horizontal band is 8 per MHz.
Based on the 0 line NTSC system, the horizontal resolution equivalent to 600 lines is 7.2MHz instead of the traditional 4.2MHz band.
It has been obtained starting from a signal source capable of providing a baseband luminance signal with a band of 5 MHz. Such a signal source consists of a high resolution camera scanning at twice the standard scanning rate and having a resolution that is at least twice that of the standard in the horizontal dimension and twice that in the vertical dimension. The high resolution signal is advantageously passed through an anti-aliasing filter to improve vertical resolution and then applied to a YIQ matrix capable of handling wideband signals. The low frequency part of the baseband luminance signal (y) is equivalent to that used in standard televisions (shown as extending from 0 to 3MHz), and is equivalent to the conventional baseband video signal. A conventional encoder (NTSC in the figure) is provided to provide the following information. However, the high frequency part of the wideband baseband luminance signal (2,
(illustrated as extending from 5 to 7.5 MHz) are applied to individual circuits containing modulators featuring a p-product shape.

The local oscillator of the modulator in the illustrated embodiment has a frequency selected to be equal to a predetermined multiple of the frequency of the color subcarrier. The predetermined multiple is selected so that the sidebands output by the modulator are not superimposed on the conventional baseband video signal spectrum. In the figure, the lower sideband has been selected by a bandpass filter. For example, to obtain a horizontal resolution equivalent to 600 lines, supplying the upper 5 MHz of the 7.5 MHz baseband luminance spectrum to the modulator would require no response to any of the conventional NTSC baseband spectrum. 3 of the frequency of the color subcarrier so as not to overlap.
It is to determine the fact that a predetermined multiple must be set to 5 times. 3.579545M
In an NTSC system with a color subcarrier frequency of Hz, the lower sideband output of the modulator is between 4.9 and 10.11v.
iHz range to avoid overlap with the conventional baseband video spectrum, which has a cutoff frequency of 4.2 MHz.

In the conventional receiver, the luminance signal and the signal of the conventional broadcast channel are the same as the untransformed conventional RF,
It can be detected by an IF and a circuit such as a video decoder. In the newly designed receiver according to the present invention, the color signal can also be detected by conventional circuitry. However, high-fidelity luminance signals are detected by heterodyning, or mixing, the signal from the high frequency channel using a local oscillator set to a predetermined multiple of the chrominance subcarrier placed in the conventional channel. Ru. The lower sideband signal generated by this mixing is then added to the conventionally detected video signal to generate an enhanced image signal with a horizontal resolution of up to 600 lines.

Furthermore, according to the present invention, the definition of color components of baseband television signals can also be improved.

In conventional NTSC color modulation schemes, high color purity reproduction degrades image details.

Thus, if you try to modulate a pure red signal, of course,
There are no green or green lights.

The luminance signal that conveys details typically consists of a 30% red component, a 59% green component, and an 11% green component; the fact that there is no blue or green signal reduces the brightness and image quality. It means to invite the surrender of details.

According to the present invention, the band-limited portions of the high frequency portions of the broadband I signal and the 9th signal are time-division multiplexed within the horizontal scanning lines of the image. Cross-luminance as well as cross-color effects involve modulating multiplexed color signals at an odd multiple of 1/4 of the horizontal sweep frequency to give a single sideband spectrum that interleaves in a manner that does not interfere with the luminance spectrum. reduced by

General Description These and other objects and features of the present invention will become apparent from the drawings and description.

FIG. 1 is a diagram illustrating the nominal baseband amplitude of a video signal at a transmitter versus frequency customization in a conventional NTSC system. The frequency of the color subcarrier F'sc is displaced from the origin by a high frequency 455 times 1/2 of the horizontal line scanning frequency FH. This relationship is chosen such that the luminance spectrum y is not actually continuous, but exists as a multiple of a group of signals (rJ not shown) centered around a harmonic of the scan line frequency FH. This is what I did. The color subcarrier F8C is set at a frequency equal to an odd harmonic of 1/2 the scan line frequency, so as to fall in the valley between two such signal groups.

The chrominance subcarrier F'sc is of square amplitude modulated by two chroma signals, conveniently designated I and Q' in FIG. The Q chroma signal reproduces colors from yellow-green to purple, while the ■ chroma signal sends out hues ranging from bluish green (cyan) to orange. The echroma signal includes a double sideband portion and a single sideband portion. The double sideband portion extends 0.5 MHz to either side of the in-phase color subcarrier.

The single sideband portion is 0.5 to 1 below the in-phase color subcarrier.
．． 5 MHz range. The narrowband Q chroma signal is double-sided and extends 0.5 MHz on either side of the square color subcarrier.

Although Figure 1 shows the nominal baseband amplitude vs. frequency characteristic at the transmitter, many modern television receivers do not use the full bandwidth of the echroma spectrum, but instead use the power and Q signals. This system straddles both sideband parts of the signal and ensures modulation well above IMHz.

In FIG. 2, the baseband amplitude versus frequency characteristic of a broadband video signal source having a luminance bandwidth of 7.5 MJ (illustrated as z) suitable for providing a horizontal resolution of 600 lines is shown.

This broadband baseband signal source is assumed to be provided by the improved camera technology described above. The required bandwidth is determined by the desired improved horizontal group resolution. Resolution is usually expressed as a function of vertical resolution and horizontal resolution. Vertical resolution refers to the number of horizontal lines that can be read and alternate between black and white in a TV picture. The horizontal resolution of the system is scaled as a function of vertical lines having the same width as the horizontal lines used to determine the vertical resolution. A cycle of horizontal bandwidth (half white horizontal scan lines, half black) contains information equivalent to two vertical scan lines, so the line, -, is a vertical line that takes into account the 4:3 aspect ratio. It must be adjusted in the same way as for resolution. Therefore, the horizontal resolution per unit video bandwidth is determined by doubling the effective horizontal scan line time divided by the aspect ratio. In an NTSC system, the effective horizontal scan line time is 53.5 μs and the aspect ratio is 4/3.

Therefore, the horizontal resolution of the NTSC system is approximately 80 lines/
It can be expressed as MHz.

Most NTSC receivers have a bandwidth of E 3 MHz and, as a result, a resolution of 240 lines.

With a source bandwidth of 7.5 MHz, a horizontal resolution of 7K with 600 lines can be achieved.

According to the present invention, the signal of the broadband luminance signal source of FIG.
It is provided for both a conventional NTSC encoder and a high pass filter. The NTSC encoder is
As shown in Figure 1, the low frequency range 4 of the 7.5 MHz luminance signal
．． Receives 2 MHz. A high-pass filter with a cutoff frequency of E 3 MHz provides a luminance output, YH, as shown in FIG. The luminance output YH is the color-subcarrier F's placed in the NTSC part of FIG.
The output of the modulator is an upper sideband signal as shown in FIG. and low (j
1U band signal. The upper sideband of FIG. 4 is discarded and the lower sideband is added to the conventional NTSC portion to produce the composite baseband amplitude versus frequency characteristic shown in FIG. 45.

Furthermore, according to the present invention, an improvement in color yield is achieved. In conventional NTSC modulation of color information, the bandwidth allocated to ζ color is narrower than the bandwidth allocated to luminance (which determines image details). For example, as shown in Figure 1, the Q component of color has conventionally been allocated to 1/8 of the luminance (Y) band, and the engineering component of color has been nominally allocated to a fraction of 1/3 of the luminance (Y) band. It is narrowly allocated. However, since the single sideband part of the ■ component is received at half the amplitude of the double sideband part, a difficult filter problem exists in the receiver, and in practice, the receiver is Q
It is assigned to a band narrower than the component. According to the invention, a larger proportion of the wide band allocated to luminance can be used for color information than in the NTSC system. This is shown in FIG. 6. In FIG. 6, the high frequency color information C' is also the effective color information Q occupied by the Y bandwidth in the NTSC system of FIG. occupies a portion.

DETAILED DESCRIPTION FIG. 7 is a block diagram of an enhanced resolution TV modulator according to the present invention. The broadband baseband signal of FIG. 2 is provided by circuit 700. The circuit 700 is of the type described in the Wendland article and is an improved video source camera 70 capable of having an output with more resolution than conventional scan edges.
1. In the figure, broadband red, green, and blue signals R,G.

A camera 701 that can function as a source of 1050 B signals is provided. The broadband R, G, B signal from camera 701 is then sent to an anti-aliasing filter by circuit 702 for removing frequency components above the Nyquist frequency.

In the camera, the image is converted into an electrical signal, and the image on the image tube is
Since the scanning process of the elephant resemblance is effectively a sampling process, the vertical resolution is typically between 0.6 and 0.70 Kel.
is determined by reducing the effective number of scan lines (total number less than the number of scan lines in the vertical blanking period) by a factor of ell). However, the band-limiting characteristics of the camera/signal source reduce the effect of Arias, resulting in 483 (525
1 so that a vertical image visibility close to -2
A Kel coefficient close to is given. The spatial frequency characteristic (MTF) of cameras and display devices is similar to the impulse response in linear circuit theory and is typically tuned by shaping the electron beam. However, a narrow MTF in the vertical direction means a wide frequency spectrum and aliasing, and a wide MTF means overlap of adjacent scan lines and low-pass filtering (defocus) in the vertical direction. In NTSC systems, the MTF is adjusted to find a compromise between aliasing and defocus.

According to the principle of the illustrated embodiment, antialiasing (prefiltering) is achieved by the circuit 7 of the encoder aft in FIG.
00 and interpolation (post-filtering) is employed in the corresponding circuit 850 of the decoder device of the receiver.

In circuit 700, the anti-aliased filtered camera signal is applied by circuit 702 to scan converter 703. The scan converter 703 is an existing (NT
SC) In order to obtain 525 signals for maximum transmission without losing compatibility with the baseband of the television receiver, remove every two of the 1050 R, C, and B signals. Wideband R at the output of scan converter 703
, G, B signals are applied to an RGI3-YIQ conversion matrix 720. Because of the wideband input of R', G, and B signals, the luminance output Y of transform matrix 720 exhibits the wideband amplitude versus frequency characteristic of FIG.

NTSC encoder, 730 is Y of matrix 720,
It receives the I,Q outputs and provides the conventional luminance output signal as well as the color output signal YL+CL to an adder 735 and provides a composite synchronization signal to circuit 745 and to the conventional NTSC color subcarrier signal tone circuit 731. If no other inputs are present, the output of summer 735 simply converts the conventional NTSC baseband signal into a final video modulator that modulates the signal width in the designated television channel by the selected video carrier frequency. It merely feeds a stage (not shown). However, according to the invention, the adder 735 has two additional inputs to be written: /, y
H/ is provided and transmitted by a final modulator stage (not shown) to the second of the two designated television channels. These two channels should preferably be adjacent channels to minimize weather effects, but widely separated channels can also be employed.

Circuit 731 receives the color subcarrier Fsc and modulator 732
acts as a local oscillator. The output frequency of the local oscillator is advantageously chosen to be 7/2 of the frequency of the color subcarrier F'sc. In the NTSC system, the H baseband chrominance subcarrier is 455x,T, and the local oscillator frequency F0 provided by circuit 731 to modulator 732 is 12,53 MHz. The signal input to the other modulator 732 is filtered by a high-pass filter 733 and then transferred to the matrix 72.
This is the high frequency portion of the wideband luminance signal YH extracted from the Y signal output of 0. Filter 733 is advantageously chosen to have a crossover frequency of about 3 MHz.

The output of modulator 732 includes two sidebands as shown in FIG. The upper sideband is suppressed in bandpass filter 734, and the lower sideband is suppressed in bandpass filter 734.

The sidebands pass to adder 735. The conventional signal YL+CL from the NTSC encoder 730 is passed through the filter 7
When combined with the broadband luminance signal YH from 34 in adder 735, a baseband output signal having the amplitude versus frequency characteristic of FIG. 5 is generated. This amplitude versus frequency characteristic is such that high definition images can be provided within the signal spectrum requiring no more than two conventional (6 MHz) video channels.

Another object of the present invention is to provide a circuit for increasing the definition of high frequency color components of a video signal. The Q output and ■ output of the conversion matrix 720 convert each color component to 1.5 MHz in the range of 0 and 5 to 2.0 MHz, respectively.
Bandpass filter for limiting to the band of 741.7
42. The band-limited outputs of the filters 741 and 742 are controlled by the scanning line selection circuit 745.
Color multiplexer 743 allows normal scanning speed (FH/
2) is sampled at 1/2. A scan line selection circuit 745 receives the composite sync output of the NTSC encoder 730 and selects the sync pulses by counting the sync pulses so that each new field starts from the first scan line from the signal output of the filter 742. There is an advantage in controlling multiplexer 743.

The high frequency color components 1, Q are alternately selected by a color multiplexer 743 and applied to a modulator 750 of the ``product type''.A local oscillator F applied to the modulator 750 of the ``product type''.

The frequency of is selected such that the modulator's cass vector interleaves the high frequency 'J4 degree spectrum of the signal from bandpass filter 734 without interference. The color multiplexer 743/ is set at half the horizontal scanning line rate (FH
Since the ■hull component and the Q color component are sampled at /2), the output spectrum of the multiplexer♀ is naturally divided into groups that are multiples of 1/2 of the line scanning speed. This grouping interferes with the brightness spectrum containing signals grouped in multiples of the prison scan rate FH. To avoid this interference, a local oscillator is added to the "product type" modulator 750. Here, there is a local oscillator.

The high frequency multiplexed color components at the output of modulator 750 are applied to bandpass filter 760 to remove lower sidebands. The upper sideband output CH' of filter 760 is applied to the input of a second adder 735. The other inputs of adder 735 are the conventional NTSC baseband signal and the high-rise VF4
The output of adder 735 provides the sixth south composite baseband signal.

Compatibility with existing receivers is immediately apparent since the low frequency portion of the composite signal (FIG. 6) can be decoded by conventional NTSC receiver circuitry. However, the illustrated embodiment of the improved decoder of the present invention also decodes the conventional NTSC spectrum with good broadband amplitude versus frequency characteristics.

An embodiment of a decoder according to the present invention is shown in FIG.

The TV signal arriving at the RF tuner, video detector, and IF stage 801 is received. That is, broadband luminance information and color information, which will be described next, are received. Therefore, stage 80
1 is wideband RF capable of receiving two nearby TV channels
tuner or individual RF tuners tuned to individual channels. In either case, the output of circuit 801 provides the baseband amplitude versus frequency characteristic of FIG. The circuit 801 is
- the circuit 802.810.812.83 at its output;
0.840.

The wideband signal of FIG. 6 from the NTSC color decoder 802801 is received and at its output the conventional (narrowband) Q and technical color signals designated as Q and IL are added to the adder 804, respectively. Supply to .805. Adders 804 and 805 are configured by serially connecting a bandpass filter 810, a single sideband demodulator 820, and a chrominance demultiplexer 825 to combine the high frequency chrominance signal obtained from stage 801 with the conventional Q signal. and electrical signals. The bandpass filter 810 outputs a color signal with a width of 1.5 MHy, extending in the range of 5 to 6-5 MHz. This signal is a replica of signal CH of FIG.

Product type demodulator 821 of band wave demodulator 820
The local oscillator frequency used by the NTSC
provided by color demodulator 802, FH/4. It is given by a frequency synthesizer 803 from the horizontal scanning frequency output FH which is offset by a certain amount. This corresponds to the process for using an odd multiple of 1/4 of the scanning line velocity adopted in FIG. Bandpass filter 82211-1.
, which limits the output of the demodulator 821 to within the range of the lower sideband signal. The signals at the output of demodulator 821 are of a time division multiplexed form. Demultiplexer 825 operates based on these multiplexed signals and provides continuous I and Q signals to adders 804 and 805, respectively.

In the demultiplexer 825, the
((2) The signal and the Q(1,) signal of the previous scan line stored in the delay line 826 are simultaneously sent to the adder 805.80.
A delay line 826 is provided corresponding to one scan line of the color information storage device so as to provide the color information storage device. Adder 805.
The composite I and Q signals at the output of 804 are the broadband outputs R-Y, G, -'Y, B-Y to adder 607.
is added to the transformation matrix 806 to generate the .

The high frequency luminance input Y to adder 807 is provided by adder 829 which receives as input the output of low pass filters 830, 831. fill. 830 is stage 80
The composite wideband video signal given by 1 is O~2.5
limited to the MHz range. The low pass filter 831 is
0 to 7 supplied by the ``product type'' adjuster 841
．． ' Send out a low sideband output of 5 MHz.

The “product type” demodulator 841 is an NTSC color decoder 80.
7/2 of the frequency of color subcarrier F8c detected by 2
It is. A local oscillator input from circuit 842 is received.

The other input to the "product type" demodulator 841 is the high frequency portion of the baseband video signal, which extends approximately from 49 to 10.1 B/IHz as shown in FIG.

The composite high resolution R, G, B signal provided at the output of adder 807 is applied to an output circuit 850 comprising a 525 line to 1050 line scan rate converter 851 and an interpolation filter circuit 852. It will be done. The interpolated R, G, B signals from circuit 852 can then be displayed on the receiver's television screen.

ffa,'r is a fully compatible, band-translated high-definition television coding and decoding scheme that modulates and modulates AM vestigial sideband signals within two standard 6MHz television channels. This has been described in the context of an NTSC environment using a possible 10 MHz baseband signal. One of the channels is as it would be received by a conventional receiver without modification. 7.51 VIHz between maximum 600 horizontal resolutions
can be achieved from a luminance signal bandwidth of The signal sources of 1050 luminance signals and chrominance signals are subjected to the action of 7 alias prevention filters to achieve a maximum vertical resolution of 483 lines. Crosstalk between the individual baseband components of the chrominance and luminance signals is avoided by non-interleaving the multiple components of the high frequency chrominance signal into the high frequency luminance spectrum.

It is believed that the circuit and amplitude characteristics described above are merely illustrative of the principles of the present invention. It is contemplated that numerous modifications may be made by those skilled in the art without departing from the spirit and scope of the invention.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the amplitude versus frequency characteristic of a conventional baseband video signal. FIG. 2 is a diagram showing the baseband amplitude versus frequency characteristic of a wideband video signal source. FIG. 3 is a diagram showing the result of applying a high-pass filter to the amplitude versus frequency characteristic of FIG. 2. FIG. 4 is a diagram showing double-band side waves obtained by modulating the signal of FIG. 3. FIG. 5 is a diagram showing the amplitude versus frequency characteristic of a composite baseband including the conventional NTSC portion of FIG. 1 and the lower sideband portion of FIG. FIG. 6 is a diagram illustrating the amplitude versus frequency characteristics of a composite baseband according to the present invention, including interleaved high frequency multiplexed chrominance signals. FIG. 7 is a block diagram of a high definition encoder according to the present invention. FIG. 8 is a block diagram of a high definition decoder of the present invention. [Explanation of symbols of main parts] 701...1050 signal source 702...Anti-aliasing filter 703.851...Scan converter 720.806...Matrix 730...Encoder 731.842... Arithmetic unit 732.750...Modulator 733.734.741.742.760.810.8
22.830.831.840...Filter 735.
804.805.807.829... Adder 743.
... Selector 745 ... Selector control device 802 ... Decoder 803 ... Frequency synthesizer 821.841 ... Demodulator 826 ... IH delay line 852 ... Interpolation filter Applicant: Western Electric Link Company, Incorporated FI6. 5

Claims (1)

[Claims] 1. A scarlet scan signal of an anti-alias filtered video signal having the number of scanning lines per frame and a bandwidth suitable for providing a desired degree of vertical and horizontal resolution. In order to generate a single sideband signal having a spectrum that does not overlap with the spectrum of the low frequency component of the baseband video signal of the baseband signal source, the method includes: Modulating the component passed through the high-pass filter of the baseband video signal with a signal having a frequency that is a multiple of the frequency of a color subcarrier provided in the low-pass component of the baseband video signal of the baseband signal source. and combining the generated sideband signal with the low frequency component of the baseband signal. 2. The method according to claim 1, wherein: - the signal for modulating the source signal that has passed the high-pass filter has a frequency ranging from the frequency of the modulation signal to the highest frequency component of the source signal; The method is characterized in that the frequency of the baseband signal is higher than the highest frequency of the low-frequency component of the baseband signal. 3. In the method according to claim 1, the band-limited portions of the high-frequency color signal included in the signal source signal are multiplexed sequentially between horizontal scanning lines, and the generated sidebands are multiplexed. In order to incoherently interleave the high-frequency luminance spectrum of the wave signal to provide a single sideband envelope spectrum, the multiplexed band-weight limited color signal is multiplied by an odd multiple of 1/4 of the line scan rate. 4. The method according to claim 3, wherein a line scanning synchronizing signal is output from the color subcarrier, and each of the predetermined components of the color signal is modulated. New image
A method comprising: controlling said multiplex responsive to said synchronization signal to initiate a synchronization signal.