CA1314620C - Multiplex tv signal processing apparatus - Google Patents

Multiplex tv signal processing apparatus

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Publication number
CA1314620C
CA1314620C CA000562168A CA562168A CA1314620C CA 1314620 C CA1314620 C CA 1314620C CA 000562168 A CA000562168 A CA 000562168A CA 562168 A CA562168 A CA 562168A CA 1314620 C CA1314620 C CA 1314620C
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Canada
Prior art keywords
signal
multiplex
television signal
television
amplitude
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CA000562168A
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French (fr)
Inventor
Yoshio Yasumoto
Sadashi Kageyama
Shuji Inoue
Yoshio Abe
Hideyo Uwabata
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Panasonic Holdings Corp
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Matsushita Electric Industrial Co Ltd
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Priority claimed from JP62074709A external-priority patent/JPS63240279A/en
Priority claimed from JP62074713A external-priority patent/JPS63240282A/en
Priority claimed from JP62182523A external-priority patent/JPS6425685A/en
Application filed by Matsushita Electric Industrial Co Ltd filed Critical Matsushita Electric Industrial Co Ltd
Application granted granted Critical
Publication of CA1314620C publication Critical patent/CA1314620C/en
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Abstract

ABSTRACT OF THE DISCLOSURE

A multiplex television signal processing apparatus includes a signal separator to separate a multiplex signal into first and second parts; a time-multiplexer to time-multiplex a main television signal and the first part of the multiplex signal to obtain a time-multiplexed main signal; a first amplitude-modulator for modulating a first carrier by the multiplexed main signal to obtain a vestigial sideband, amplitude-modulated main signal; a second amplitude-demodulator for modulating a second carrier by a second multiplex signal; an inverse Nyquist filter for filtering this signal to obtain a vestigial sideband, amplitude-modulated multiplex signal; and an adder for adding the vestigial sideband, amplitude-modulated main and multiplex signals to obtain a multiplexed signal. The apparatus also includes. a Nyquist filter-for filtering the multiplexed signal; a carrier regenerator for regenerating the first and second carriers from the multiplexed signal; a main signal detector for detecting the main signal from the multiplexed signal passed through the Nyquist filter by using the first carrier; a filter for removing quadrature distortion from the multiplexed signal; a multiplex signal detector for detecting the first multiplex signal from the multiplexed signal passed through he filter by using the second carrier; a time-demultiplexer for time-demultiplexing the main signal into a main television signal and a second multiplex signal; and a signal composer for composing the first and second multiplex signal to obtain the original multiplex signal.--.

Description

G~

SPECIFICATION

TITLE OF THE I~ENTION
Multiplex TV signal processing apparatus BACKGROUND OF THE INVENTION

1. Field of the Invention This invention relates to an apparatus for multiplexing a specific signal with an amplitude modulated television signal, transmitting and receiving the multiplexed signal, and extracting the specific signal from the, multiplexed signal.
2. Description of the Prior Art.
More than 30 years have passed since the color television broad-casting of the current NTSC (National Television System Commit-tee) system began in 1960. RecentLy, in search of finer defini-tion and hi~her performance television system, several new sys-tems including HDTV (High Definition Television) system developed by NHK( The Japan broadcasting Corpora-tion) have been proposed.
At the same time, the contents of the programs presen-ted to vie~ers have been changed from the mere studio programs to pro-grams providing higher quality images and more realistic feeling such as cinema-si~e movies.
The current NTSC broadcasting is standardized by 2:1 interlaced c~

525 scanning lines, luminance signal bandwidth of ~.2MEz, and as-pect ratio of 4:3. (See, for example, Pritchard, "US Color Television Fundamentals -~ Review", I~EE Trans. Consumer Elec-tron.~ vol. CE-23, pp.467-478, Nov. 1977.) In this background, several television slgnal composition methods aiming at compatibility with the current broadcasting system and enhancement of horizontal resolution have been pro-posed. One of such examples is presented in a paper of Fukinuki and Hirano, "Extended Definition TV Fully Compatible with exist-ing Standards", IE~E Trans. Commun., vol. COM-32, pp.948-953, Aug. 1984. Considering the NTSC television signal expressed on a t~o-dimensional plane of temporal frequency fl and vertical fre-quency f2, chrominance signals C are present in the second and fourth quadrants due to the phase relations to the chrominance subcarrier fsc. The Fukinuki et al example uses the vacant first and third quadrants or multiplexing the high frequency com-ponents of luminance signal. The chrominance signal and the mul-tiplex high frequency components are separated and reproduced at the receiving end, thereby enhancing the horizontal resolu-tion.
In this example, the conventional NTSC receiver would be inter-ered by the multiplex signal, because the example has no ability for separating the chrominance signal from the multiplex high frequency components.
In the current television broadcast, as clear from the descrip-tion above, signal bandwidth is limited by the standard, and it is not easy to add some new information in good quality. For ex-! 6 ~ ~

ample, other methods to enhance the horizontal resolution are proposed (M. Isnrdi et al, "A single Channel NTSC Compatible Widescreen EDTV System", HDTV Colloquim in Ottawa, Oct., 1987), but many problems are left unsolved from the viewpoint of the compatibility with the current television broadcasting and deterioration of demodulation characteristics of high frequency components in a moving picture. Besides, from the standpoint of effective use of the frequency resources, the transmission band cannot be extended as an easy way.
The present inventors have previously invented a method of superposing a signal by using quadrature modulation of the video carrier. (U.S. Patent No. 4,882,614) By this method, various signals can be transmitted using newly established ~uadrature channel and the interference to the conventional NTSC receiver is very small in principle. But the interference can be detected in practice, because of the incompleteness of characteristics of filters at the receiver and transmitter.
This invention is on~ of solutions to this practical problem when quadrature modulation is carried into practical use. Even if the incompleteness of such circuits as filters occurs, the interference to the conventional NTSC receivers can be reduced down to the acceptable level. In this sense, this invention is very useful when ~uadrature modulation of the video carrier is implemented.

SUMMARY OF THE INVENTION

@-- ~

It is a primary object of this invention to provide a multiplex signal processing apparatus for multiplex transmission of a large ~uantity of information in a limited bandwidth without interfer-ence to the current receiver.
According to this invention, a multiplex signal processor at a transmitter side replaces hidden portions of the main NTSC signal (the portions which are not displayed on a screen by over-scanning of a receiver) and front porch of horizontal synchronous signal of the main NTSC signal uith a first specific multiplex signal, amplitude-modulates a main video carrier by the main sig-nal to obtain a vestigial side band (VSB) signal, and amplitude-modulates a carrier which is same in frequency as and shifted in phase by 90 degrees from the main carrier by a second specific multiplex signal to obtain a double side band signal. The modu-lated multiplex signal is passed through an inverse Nyqùist filter to obtain a vestigial side band (VSB) signal, and then su-perposed on the modulated main signal to obtain a multiplexed signal, which is transmitted.
A multiplex signal processor at a receiver side has a synchro-nous detector and a quadrature distortion eliminating filter for demodulating the main and multiplex signals from the multiplexed signal received.
~ y this constitution, it is possible to obtain not only the con-ventional television broadcasting images but also multiplex in-formation at the receiver, by generating a television signal ca-1 3 1 Ll 6 2 0 pable of multiplex trans~ission of o-ther information within the standard band of the existing television broadcasting.
As an example, if side panels (signals which correspond to -the left and right sides of a whole image) of a wider aspec-t picture than the conventional 4:3 are transmitted as the first and second multiplex signals, the ~ider aspec-t picture can be generated at a receiver end from the main signal(4:3 NTSC) and the multi21ex signals(side panels). In this case, low and high frequency com-ponents of the side panels can be transmitted as the first and second multiplex signal, respectively. DC component of -the first multiplex signal can be easily transmitted, so as to keep con-tinuity between the side panels and center panel ( signal which corresponds to the ~:3 aspect ratio image). On the other hand, the second multiplex signal can be easily scramoled to reduce the interference to the conventional receivers.
3y employing the above mentioned techniques, when the multiplex signal is received by an e~isting television receiver, -there is almost no interference by the mul-tiplex signal. In other words, -the compatibility with the existing television receivers c~n be main-tained. Furthermore, the fea-ture that multiplex transmission of other information is possible in a fre~uency band determined by the standard is very advantageous also from the viewpoi.nt of effec-tive use of frequency resources.

BRIEF DESCRIPTIO~T OF THE DR~WINGS

1 3 1 4 62() Fig. 2, Fig. 12 ~a), Fig. 16(a), and Fig. la(a) are block di-agrams each showing a multiplex signal processor at the transmis-sion side embodying this inven-tion;
Fig. 4(c), Fig. 12(b~, Fig. 18(b), and Fig. 16(b) are block di-agrams each showing a multiplex signal processor at the reception side embodying this invention;
FigsO 1 (a)-(c) and Figs. ll(f)-(j) are spectral diagrams show-ing the processing method OI the multiplex signal processor at the transmission side according to this invention;
FigO 4~a) is a spectral diagram showing the processing method of the multiplex signal processor at the reception side according to this invention;
EigO 4(b) is a vector diagram to explain the principle of the multiplex signal processor at the reception side according to this invention;

. .
Figs. 3(a), (~), and (c) are block diagram, spectral diagram, and vector diagram s~o~ing a conventional television receiver . _ ~ .. . .
when receiving the composite signal generated by the mul-tiplex signal processor;
Fig. 5 shows wave forms to explain the function of the signal separator;
Fig. 6 is a block diagram of the signal separator;
Figs. ll(a)-(e) are signal waveform diagrams showing the signal processing steps in Fig. 6 according to this invention;
Fig. 7 is a block diagram of the signal composer;

Fig. a is an example of display screen of existing television ¢ - -~31~62~

and a time-axis e~pression of composite video signal;
Fig. 9 is an example of display screen with aspect ratio of 5:3 and time-axis expression of composite video signal;
FigO 10 is a picture composi-tion at different aspect ratio;
Fig. 13(a) is an internaL circuit composition of a signal gen~
erator 125 in Fig. 12(a);
Fig. 13(b) shows an example of discriminating signal;
Fig. 14 is an internal circuit composition of a signal separator 131 in Fig. 12(b), Fig. 15 is an internal circui. composition OI a signal selector 137 in Fig. 12tb).
Figs. 17(a) and (c) are block diagrams of IWo e~amples of the scramblerO
Fig. 17(b) is a figure to explain the scrambled picture.

DETAIL~D DESCRIPTION OF THE PREFERRED EMBODIMENTS

Figs. 1 ta)- (c) are spec-tral diagrams to show a television sig-nal processing method at the transmission side. More specifical-ly, Fig. lta) is a spectral diagram of a vestigial side band, am-plitude modulated television signal in the NTSC television sys-tem, in which the lower side band of a video carrier P1 is the vestigial side band. In this case, the signal may be an~ -televi-sion signal amplitude rnodulated, and thus it is not limited to the NTSC television slgnal.
Fig. l(b) is a spec~rum of a signal which is obtained by ampli-1 3 1 ~ ~20 tude modulating a multiplex signal by a carrier P2 which is same in frequency as and different in phase by 90 deyrees from the video carrier Pl and passing the modulated signal -through a spe-cial filter which is called "inverse Ny~uist filter". The fre-~uency characteristic of the inverse Nyquist filter is -6dB at frequenc~ P2, infinite attenuation at P2+1.25MHz, and no attenua-tion at P2-1.25MHz. Preferably, the carrier P2 is removed in the blanking period of the main television signal.
The signal shown in Fig. l~b) is multiple-~ed with the main television signal shown in Fig. l(a) to obtain a composite signal as shown in Fig. l(c). The multiplex signal may be either analog signal or digital signal.
Fig. 2 is a block diagram showing a television multiplex signal processor at the transmission side as an embodiment of this in-vention. A main signal generator 601 genera~es a main signal such as a video base band signal. A multiplex signal generator 602 generates a multiplex signal which is either analog or digi-tal signal. The main and multiplex signals are fed -to a multi-plex signal superposing circuit 13 through input terminals 10 and 11, respectivel~l.
In the multiplex signal superposing circuit 13, the multiplex signal is separated at a signal separator 6 into two parts, one of which is multiplexed with the main signal at a time multipler 1, and the other is amplitude-modulated at an amplitude modulator 7.
~ig. 5 shows the function of the time multiplexer 1 in the case l3~ .a that -the main signal is the video base band signal. In Fig. 5, a wave form (a) shows a composite video base band signal with a horizontal synchronous signal and a burst signal of chrominance subcarrier, (b) shows a multiplex signal from -the signal separa-tor 6, and (c) shows a time multiplexed signal which is outputted from the time multiplexer 1~ In this case -the multiplex signal from -the signal separator 6 is multiplexed at the hidden portions of over-scanning and front porch of hori~ontal synchranous signal of the main video base band signal. By the main signal coming from the time mul-tiplexer 1, the video base band signal multi-plexed with a part of multiplex signal, a carrier Pl generated by an oscillator 4 is amplitude- modulated at an amplitude modulator 2. The obtained modulated signal is filtered by a VSB filter 3 to become a vestiaial side band signal, which is fed to an adder 9. The VSB filter 3 is a filter to transform a dcuble side band signal into a vestigial side band signal. The carrier Pl from the oscillator 4 is shifted in phase by 90 degrees a-t a phase shif-ter 5 to be a carrier P2.
Fig. 6 shows an example of the signal separa-tor 6.
In Fig. 6, -the multiplex signal generated by the multiplex sig-nal generator 602 is fed to a low-pass filter 610 and a subtrac-tor 611. Low frequency component of the multiplex signal from the low-pass filter 610 is fed to a time compression circui-t 612 and the subtrac-tor 611. The low frequency component is time-compressed at the time compression circuit 612 and fed to the time multiplexer 1. On the other hand, high frequency component 1 3 1 4 ~21~) of the multiplex signal is ob-tained at -the subtractor 611 and time-expanded at a time expanding circuit 613 to a narrower bandwidth signal, which is fed to the amplitude modulator 7. In this example, the input multiplex signal is separated by its fre-quency. Alternatively, any other attribute such as an amplitude and time of the input signal can be a factor of the signal separator.
Referring back to FigO 1, by one of the two parts of the mul-ti-plex signal separated by the signal separator 6, the carrier P2 is amplitude-modulated in double side band at the amplitude modu-lator 7, and preferably in the blanking period the carrier is suppressed. The phase shift direc~ion of the phase shifter 5 may be either fixed or varied at intervals of horizontal scanning period, field or frame. The modulated multiplex signal is limit-ed in the band by an inverse ~yquist filter 8, and then fed to the adder 9. The amplitude rrequency charac-teris~ic of the in-verse Nyquist filter 8 is symmecrical to an amplitude frequency charactsristic immediately before video detection at -the receiver with respect to the video carrier.
The output of the adder 9 is a composite signal. That is, the modulated multiplex signal is su~erposed on the modulated video base band signal at the adder 9 to obtain the composite signal.
The composite signal appearing at an output terminal 12 of the multiplex signal supe:rposing circuit 13 is transmitted from a transmitter sa with an an-cenna 59. The transmission path is not limited to the wireless sys-tem, but may be a wired system. In 1 3 1 L!7~20 this example, the composite signal is obtained by adding the out-puts of the VS~ filter 3 and the inverse Nyquist fil-ter 8, but it is also possible to feed the sum of the outputs of the amplitude modulator 2 and the inverse Myquist filter 8 into the VSB filter
3 to obtain the composite signal.
On the other hand, a television multiplex signal processor at the reception side is as follows. The following example refers to terrestrial broadcasting of the NTSC television system, but is is not intended as limitation. Fig. 3(a) is a blocl~ diagram of an e~isting television receiver with a synchronous video detec-tor. The signal transmitted from the transmission side is re-ceived by an antenna 21, converted in frequency to an intermedi-ate frequency band by a tunner 22, and limited in the band by a Nyquist fil-ter 23. The band-limited signal is fed in-to a video detector 24 and a carrier regenerator 25. In the carrier regen-erator 25, the video carrier I1 or synchronous detection is re-generated. The band-limited signal is synchronously detected by the carrier I1 at the video detector 24 to obtain the main sig-nal, that is the video base band signal, at an output terminal 26.
The frequency characteristic of the Nyquist filter 23 is as fol-lows. Referring to Fig. 3(b) which shows the frequency charac-teristic of the Nyquist filter 23, the amplitude is attenuated by6dB at the video carrier I1, and the Nyquist filter characteris-tic possesses nearly an odd~symmetrical amplitude property with respect to the video carrier I1.

1 3 i ~620 On the other hand, as shown in Fig. l(b), when the multiplex signal is limited in band by the inverse Nyquist filter 8 in the transmitter having an inverse characteristic to the frequency characteristic of the Nyquist filter 23 in the receiver, the mul-tiplex signal components in the shaded area in ~ig. 3(b) is near-ly double side band. This can be expressed by a vector diagram as shown in Fig. 3(c), in which Il is the video carrier of the main signal, tha-t is, the video base band signal, and I2 is the carrier of the multiplex signal which carrier is same in frequen-cy as but dif erent in phase by 90 degrees from Il. The video base band signal is a vestigial side band with respect to the carrier Il, so that the upper and lower side bands are vector aU
and vector aL, respectively, which are Veclor al and vector a2, respectively, when decomposed into orthogonal vectors. Since the upper and lower side bands of the multiplex signal are expressed by vector bU and vector bL, respectively, their synthetic vector is b2, which is only the component to intersect with vector Il orthogonally.
That is, when the main signal is synchronously de-tected by the carrier Il, quadrature distortion due to the vector a2, vector b2 components does not occur. Thus, the impairment by the multiplex signal to the existing television receiver performing video syn-chronous de-tection does not occur in principle.
Next, detection of the multiplex signal at the reception side is described below. The signal of the video intermediate frequency band which is the output of the tuner 22 is limited in band by a 1314~

band-pass filter, as shown in ~ig. 4(a), so that the main signal, that is, the video base band signal, becomes double side band.
Its vector expression is shown in Fig. 4(b). Since the multiplex signal is vesticTial side band, the upper and lower side bands are vector bU and vector bL, respectively, their synthetic vector is al, which is only the component intersecting orthogonally with the vector I2.
That is, ~hen the multiplex signal is synchronously detected by the carrier I2, quadrature distortion due to the vector al, vec-tor bl components does not occur. Thus, oniy the multiplex sig-nal components can be demodulated.
Fig. 4(c) shows an example of television multiplex signal pro-cessor for demodulating the multiplex signal as ~ell as the main signal. The multiplexed signal transmitted from the transmission side is received by an antenna 31, converled in frequency into an intermediate fre~uency band by a tuner 32, and fed to a multiplex signal separator 44 through an input terminal 41 thereof. The fed signal is limited in the band by a ~Tyauist filter 33. The band-limited signal is ~ed to a video deteclor 34 and a carrier regen-erator 35. In the carrier regenerator 35, the video carrier Il for synchronous detection is regenerated. The band-limited sig-nal is synchronously detected by the carrier Il in the video detector 34, and fed to a time demultiplexer 36. In the time demultiplexer 36 the main signal and the first multiplex siynal are separated. This processing is just the opposite to that of the time multiplexer 1 in the multiplex signal superposing cir-1 3 1 L'l ) 2 0 cuit 13 at the transmission side. The first multiplex signal isfed into a signal composer 40 and the main signal, -the base band video signal, goes to an ou-tput terminal 42 of the multiplex si~-nal separator 44.
The main signal is converted into, for example, R, G, B sisnals by a main signal processor 603, and displayed on a CRT screen 1000 .
The output of the tuner 32 is band-limi-ted also as shown in rigO
4(a) b~ a band-pass filter 37. By the carrier I2 obtained by 90 degrees phase shifting the carrier I1 by a phase shifter 3a (that is, by the carrier I2 in the same phase as the carrier for mul~i-plex signal modulation used at the transmission side), the band-limited signal is synchronously detected in a multiplex signal detector 39 to obtain the second multiplex signal. The second multiplex signal is composed into the original multiplex signal together with the i-irst multiplex signal a-t the sisnal composer 40.
Fig. 7 shows an example of the signal composer 40. In this fig-ure, the first multiplex signal from the time demultiple:rer 36 is time-expanded at a time expansion circuit 401. The second multi-plex signal from the muLtiplex signal de-tector 39 is added to the time-expanded first multiplex signal at an adder 402. The com-posed multiplex signal, which is the output of the adder 402, is fed to an output terminal 43 of the multiplex signal separa~or 44. In the multiplex signal generator 604, the composed multi-plex signal is subjected to the reverse processing to the pro-1 3 1 4 ~20 cessing by the multiplex signal generator 602 at the transmissionside.
As described above, in the existing receiver, since the multi-plex signal is substantially canceled by the synchronous detec-tion by the video carrier I1, the main signal is not interfered by the multiplex signal. Further, in the recsiver capable of demodulating the multiplex signal, not onl~ the main signal, that is, the video base band signal, is obtained in the same way as above, but also the multiplex signal can be also obtained without quadrature distortion by filtering and synchronous detaction by the carrier I2. This is not limited to the ~TSC television sys-tem, and can be applied to any system as far as the main signal is amplitude-modulated in the vestigial side band.
Fig. 8 and Fig. 9 show the conce?t of a wide-screen television system. In these figures, the as~ect ratio of the wide-screen television system is assumed to be 5:3 bu~ it may not be limited to such ratio. In Fig. 8, the present NTSC picture (a) and its corresponding wave form (b) are depictad, in which a circle and 2 arcs are displayed on the 4:3 frame. Fig. 9 shows 5:3 picture (a) and its corresponding wave form (b), in which 3 circles are displayed. Only when we see 5:3 picture in Fig. 9, 3 circles are recognized. For this purpose of clear recognition, side panels should be transmitted as the multiplex signal.
Fig. 10 shows the difference between the aspect ratios of the conventional NTSC system and the wide-screen television system.
In this figure, (s) means side panels which is treated as one signal and transmitted as the multiplex signal and (M) means c~nter panel which corresponds to the present 4:3 frame (the main signal).
These side panels and cen-ter panel have the same frequency band, but the band width of the mul-tiplex signal should be, at most, 1.25MHz according to the above explana-tion. Figs. 11 (a)-(j) show wave forms and power spectrums of various points of the signal separator 6 in Fig. 6. Fig. ll(a) is the multiplex signal which corresponds to the two parts of side panels. Fig. ll(f) shows a typical power spectrum of the above multiplex signaln First, the input multiplex signal (Fig. ll(a)) is fed to the low-pass filter 610, where the low freauency component (Fig.
ll(b) shows its wave form and (g) shows its power spectrum) is obtained. This signal is time-compressed at the time compression circuit 612 which bandwidth is increased up to that of the origi-nal signal. Fig. ll(c) shows this time-com~ressed signal and (h) shows its power spectrum. On the other hand, the high frsauenc~
component (Fig. ll(d) shows its wave forn and (i) shows its power spectrum ) is obtained at the subtractor 611. This signal is time-expanded at the time expanding circuit 613. Fig. 11 (e) shows the wave ~orm o-f -the time-expanded signal and (j) shows its bandwidth which is, at most, 1.25~Hz.
Thus, the multiplex signal is subjected to time-a;~is processing to be separated to two parts, one of which is transmitted through the main channel replacing the hidden portion of over scanning and front porch of synchronous signal, and the other is transmit-1 3 1 4~2'J

ted through ~uadrature modulation of the video carrier.
Fig. 12(a) is a block diagram showing a television multiplexsignal processor with a wide aspect ratio at the transmission side. In Fig. 12(a), the signal fed to an input terminal 111 is a luminance siynal Y obtained from a signal picked up by a camera having a wider aspect ratio (for instance, 16:9) than the exisl-ing one, the signal fed to an input terminal 114 is a wide band chrominance difference signal I obtained from the same picked-up signal, and the signal fed to an input terminal 117 is a narrow band chrominance The luminance signal Y enters a signal distributor 112, to be distributed into a time-axis expanding circuit 113 and an adder 123. Similarly, the wide band chrominance difference signal and the narrow band chromlnance signal Q enter respective signal distributors 115 and 113, to be distributed into time-axis ex-panding circuits 116 and llg, respectively, and a balanced modu-lator 122. EacA of the time-axis expanding circuits tlme-expand the entered signal by, for example, varying the writing and read-ing clocks of a memory provided therein.
When the original picture is picked up at an aspect ratio of m:3 (m is a real number not smaller than 4 ) stretcned laterally, the picked-up signal corresponding to the portion displayed on the screen of the existing television receiver is expanded in the time-axis by m/4 times in the time-axis expanding circuits 113, 116, 119.
~ext, of the chrominance difference signals distributed by the 1 31 462a signal distriDutors 115, 118, the remaining chrominance differ-ence signals other than those expanded by the time-axis expandinc circuits 116, 119 are modulated by the halanced modula-tor 122 r and are combined with the remaining luminance component other than the luminance signal expanded by the time-axis expanding circuit 113 by the adder 123. The output of the adder 123 is fe(l into the multiplex signal superposing circuit 13 through the mul-tiplex signal input terminal 11 as a multiplex signal.
The output signals of the time-axis expanding circui-ts 116, 119 are modulated by a halanced modulator 120, and the outpu-c of -the balanced modulator lZ0 is added by an adder 121 to the output signal from the time-axis expanding circuit 113 and a synchronous signal, a burst signal and a discriminating signal which are pro-duced at a signal generator 125. The discriminating signal is for distinguishing -the composite television signal of this pro-cessor from the conventional television signal. The discriminat-ing signal may be, for example, superposed in the vertical blank-ing period.
The ou-tpu-t of the adder lZ1 is fed into the multiplex signal su-perposing circuit 13 through the main signal input terminal 10 as a main signal. The output of the multiplex signal superposing circuit 13 appearing at the terminal 12 is a composi-te signal in which the multiplex signal is superposed on the video base band main signal. The composite signal is transmitted -through -the transmitter 58 and the antenna 59.
Fig. 13(a) is a block diagram of the signal genera-tor 125 in 1 31 4~20 Fig. 12(a~, in which a synchronous signal generator 126 and a burst signal generator 127 generate a synchronous signal and a burst signal, respectively, which are the same as those in the conventional broadcasting system.
A discriminating signal generator 12a generates a discriminating signal to distinguish whether a picture o~ the wide aspec-t ratio is sent out or not. The discriminating signal is, for example, a pilot signal OI the like superposed in -the blanking period as shown in Fig. 13(b). The sum o~ the outputs of these three gen-erators 126, 127, 12a, is delivered as an output from t~e signal generator 125.
Fig. 12(b) is a block diagram showing a television multiplex signal processor with a wide aspect ratio at the reception sideO
The composite signal transmitted from the transmission side like ~he one as shown in ~ig. 12~a) and received via an antenna 31 and a tuner 32 is separated at a multiplex signal separator 44 into the main signal and the multiplex signal, which are respectively delivered from a main signal output terminal 42 and a multiplex signal output terminal 43 of the multiplex signal separator 44.
The video base band signal which is the main signal is separated in-to the luminance signal Y and the chrominance signal C by a ~C
separator 132. The signal Y is compressed in the time-axis by a time-axis compression circuit 134 to become a signal Y1. The signal C is separated into the chrominance difference signals I, Q by an I,Q demodulator 133. The signal I is compressed in the time-a-xis by a time-axis compression circuit 135 to become a sig-nal I1. The signal ~ is compressed in the time-axis by a time-axis compression circuit 136 to become a signal Q1. The multi-plex signal is compressed in the time-axis by a time-axis compression circuit 138, and then is separated into siynals Y2~
I2 and Q2 by a YC separa-tor 139 and an I,Q demodulator 140. The signals Y1, I1, Q1, Y2, I2 and Q2 are fed into a signal selector 137, in which the signals Y1, I1 and Q1 are selected -for the por-tion corresponding to the center panel of the conventional telev-ision receiver with aspect ratio of 4:3. For the remainina por-tion of one horizontal scanning period, the blanking signal or the like is generated and selected when receiving the convention-al television signal, and the signals Y2, I2 and Q2 are selected when receiving said wide television sisnal. A matrix circuit 141 produces R, G, B signals from the selected signals outputed from the signal selector 137. The R, G, B signals are fed into the CRT 1000.
Incidentally, the time-axis compression circuits 13~1, 135, 13O, 138 are provided to receive the convenlional -television signal without any trouble, and to reproduce the television signal by compressing the time-axis expanded portion of the wide television signal having an aspect ratio stretched laterally. That is, as clear from the comparison between Fig. 8~b) and Fig. 9(b), it is necessary to compress the time-acis of the conventional televi-sion signal in order to receive the picture o-f the existing broadcasting without changing the aspect ratio. The compression ratio is determined by the aspect ratio.

131462n The signal separator 131 separatest from the video base band signal, the discriminating signal for distinguishing the televi-sion signal of the existing broadcasting from the synchronous signal, color burst signal, and the wide television signal. The signal selector 137 is controlled according to this discriminat-ing signal.
Fig. 14 is a block diagram of the signal separator 131 in Fig~
12(b), which comprises a gate circuit 144. The video base bancl signal which is the main signal is fed to the gate circuit 144.
The discriminating signal is separated from -the video base band signal by the gate circuit 144. Since the discriminating signal is superposed, for example, in the blanking period of the video base band signal, its separation is easy.
Fig. 15 is a block diagram of the signal selector 137 in Fig~
12(b). If it is judged that the received signal is not ~or a picture with wide aspect ratio by the discriminating signal, the signals Y1, I1 and ~1 are selected by selec~ors 1~5 and 147, and a blanking signal generated by a blanking signal generator 14a is selected in the blanking period. If it is judged tha-t the re-ceived signal is for a picture with wide aspect ratio by the discriminated signal, the signais Y2, I2 and ~2 are selected by the selectors 146, 147.
The signal expanded in the time-axis is widened in the band when it is time-axis-compressed at the reception side, and therefore the resolution is not lowered even if the aspect ratio becomes larger. The multiplex signal not appearing on the screen of as-~-.~

1 3~ 4i~)20 pect ratio of 4:3 is nearly canceled in the conventional receiver by synchronous detection using the video carrier, so that in-terf~rence by the multiplex signal hardly occurs. In the widescreen receiver, the multiplex signal containing video signal to be displayed on the side portions of a wide aspect ratio screen is reproduced by filtering and synchronous detection using the phase-controlled carrier without quadrature distortion. When the television signal having the conventional asoect ratio of 4:3 is received, it is displayed near the middle of the screen OI as-pect ratio of 5:3, and the both sides of the screen are, Eor ex-ample, blanked.
Fig. 16(a) is a block diagram OI another multiplex sisnal pro-cessor at the transmission side. The difference be~ween Fig. 2 and Fig. 16(a) is the presence of a scrambler 51. The main func-tion of this scrambler is to reduce the interference to the con-ventional television receiver uith an envelope video detector or quasi-synchronous video detec-tor caused by the quadrature modula-tion by the multiplex signal. This scrambler is also used to use wide-screen television system as a pay television. There are many methods of scrambling, such as frequenc~ inver-ting, time-axis in-verting, e~changing line(s) by line(s), changing left side panel and righ-t side panel, changing polarity of the multiplex signal line by line, and changing polarity of the multiple~ signal field by field.
A multiplex signal generated by the multiplex siynal generator 60~ is fed to the signal separator 6 and separated , for example, 1 3 1 4` 6 ~ O

by frequency to two parts. The first part, low frequency com-ponent, of the multiplex signal is fed to the time multiplexer 1 and processed as described before, and the second par-t, high fre-~uency component, of the multiplex signal is fed -to -the scrambler 51.
Fig. 17(a) shows a block diagrarn of a first example of the scrambler 51. In this example, the input multiplex signal is stored in a frame memory and retrieved therefrom according to a control signal from a timing generator 514. The multiplex sig-nal, normally high frequency component, comes to -two frame store buffers 511 and 512, and retrieved therefrom according to the control signal from the timing generator 514. The control signal is superposed in the vertical blanking period of the multiplex signal, for example.
Fig. 17(b) shows a displa-~ screen of scrambled multiplex signal.
The left screen is the original multiplex signal at the input of this scrambler and the right screen is the ou-tpu~ of the scram-bler. In this example, the original multiplex signal is separat--ed into three parts which are transposed wi-thin a field or frame.
With the same block configuration as -that shown in Fig. 17(a), other scramble rnethod sucn as exchange of the left side and right side, polarity change line by line and so on, can be possible only if the ad~ress to frame buffers is changed.
Fig. 17(c) is another example of the scrambler 51 in Fig. 16(a).
In this example, the input multiplex signal is fed to a modulator 515 and modula-ted by a subcarrier fs from a subcarrier generator 517. rrhis modulator may be an amplitude modulator and fs rnay be fsc/3 (fsc: subcarrier of chIominance si~nal, 3.5795~5MHz). The modulated multiplex signal is fed to a band-pass filter 516. In this case, if fs is about l.ZMHz and the pass-band frequenc~ of the band-2ass filter 516 is from 0.16MHz to 1.2~Hz at -6d~
points, the output signal from the band-pass filter is jus-t fre-quency inverted to the original multiplex signal.
The power spectrum of the original multiplex signal is just like the one shown in Fig. ll(j), so the inverted multiplex sisnal has lower power at low fre~uency componenl and higher power at high frequency component.
From the spectral diagram shown in Eig. 3(b), the power of the quadrature multiplex signal at an existing television receiver is low at higher component and high at lower component. From this reason, the effect of this example is that the possible cross~alk to an existing receiver from the multiplex channel is smaller than the original superposing circuits in Fig. 2.
In the example shown in Fig. 17(c), subcarrier fs is superpos2d on the multiplex signal at a superposer 513, for exampLe, in the vertical synchronous period, in order to descramble at the recep-tion side.
Fig. 16 (b) is a block diagram o-f a multiplex signal processor at the reception side for receiving the multiple~ed signal transmitted -from the transmission side such as the one shown in ~ig. 16(a). The multiplexed signal transmitted from the -transmission side is received by the antenna 31, conver-ted in 1 3 ~ '~ 6 ,` ~3 fre~uency into the intermediate frequency band by the tuner 32, and limited in the band by the ~Jyquist ~ilter 33. The band-limited signal is supplied into the video detector 34 and the carrier regenerator 35. In the carrier regenerator 35, a video carrier Il for synchronous detection is regenerated. The band~
limited signal is detected by the carrier Il in the video detec-tor 34, and fed to the time demultiple~er 36. In this demulti-plexer the main signal and the first multiplex signal are separated. The first multiplex signal is, for example, superposed in the hidden portion of over scanning of -the television recei~er and/or the front porch of the horizontal synchronous signal~
This processing is just the opposite of those of the time mul_i-plexer 1 in -the multiplex signal superposing circuit 13 a-t the transmission side shown in Fig. 16 (a). The second multiplex signal is fed into a descrambler 52 and descrambled. This pro-cessing is just the opposite to that a~ the scramnler 51 of the transmission side and per~ormed according -to the superpose~d con-trol signal, for example, the signal showing which line(s) is transposed to which line(s). After -the multipls~ signal is descrambled at the descrambler 52, it is fed in~o the signal com-poser 40 and composed with the first multiplex signal. Finally, -the composed multiplex signal goes to the output terminal 43.
Fig. la(a) shows a block diagram of still another multiplex sig-nal processor at the -transmission side. This figure shows another version of the multiplex signal superposing circuit 13 uhich per-forms an alternative ~uadrature amplitude modulation. By chanq-1 31 ~S2(~

ing the polarity of amplitude modulation line by line, or field by field, the interference to an existing television receiver is reduced, or at least it becomes less sensitive to vie~ers. In Fig. 18(a), an amplitude modulator 55 is added and a selector 56 switchs modulated signals Erom the amplitude modulator 7 and the amplitude modulator 2 according to the defined seqùence.
Fig. 18(b) sho~s a bloc~. diagram of a multiplex signal processor at the reception side for receiving the multiplex signal generzt-ed by the processor such as the one shown in Fig. 18(a). This figure shows another version of the multiplex signal separator 44 which includes an alternative detector. By detecting the amplitude-modulated signal as a positive modulation or a negative modulation alternatively, the multiplex signal is success~ully demodulated. The modulated signal from the band-pass filter 37 is fed to both of a multiplex signal detector 39 and a multiplex signal detector 57 and detected.
The generated carrier I2 is fed to both of the two multiplex signal detectors 39, 57. The detected multilex signals, one of which is positive and another is negative, are fed to a selector 5a and selected according to the defined sequence. This sequence is either to be transmitted as a ~ontrol signal or -to be generat-ed within the reception side.
From the selector 5a, the original multiplex signal is outputed and processed as mentioned be~ore.
When the multiplex signal has no DC component, negative and po-sitive modulations are performed by changing the polarity of the c~
1 31 ~620 original multipLex signal- Changing the polarity of tAe multi-plex signal and changing the polarity of the carrier is und~r-stood to be equivalent.

_ _ .~ . ._ ...................................... .... , .. __ . __ .__.

... .

Claims (17)

  1. THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
    PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

    -- 1. A signal processing apparatus in a television signal transmitting system, comprising:
    a main signal generating means for generating a televi-sion signal as a main signal;
    a multiplex signal generating means for generating a multiplex signal;
    a signal separating means for separating the multiplex signal into first and second multiplex signals;
    a time-multiplexing means for time-multiplexing said second multiplex signal and said main signal to obtain a time-multiplexed main signal;
    a carrier generating means for generating a first carrier;
    a first amplitude-modulating means for amplitude-modulating said carrier by said time-multiplexed main signal to obtain a first vestigial side band, amplitude-modulated signal;
    a phase shifting means for shifting the phase of said first carrier by 90 degrees to obtain second carrier;
    a second amplitude-modulating means for amplitude-modulating said second carrier by said first multiplex signal to obtain a double side band, amplitude-modulated signal;
    an inverse Nyquist filter having a Nyquist characteris-tic for filtering said double side band, amplitude-modulated signal to obtain a second vestigial side band, amplitude-modulated signal;
    an adding means for adding said first and second vestigial side band, amplitude-modulated signals to obtain a resultant multiplexed signal; and a transmitting means for transmitting said resultant multiplexed signal.
  2. 2. An apparatus according to claim 1, wherein said second amplitude-modulating means has a means for removing said second carrier from said double side band, amplitude-modulated signal in periods corresponding to blanking intervals of said television signal.
  3. 3. An apparatus according to claim 1, further comprising a means for generating a discriminating signal for signal identification, and a means for superposing said discriminat-ing signal in a vertical blanking interval of said first multiplex signal.
  4. 4. A signal processing apparatus in a television signal receiving system for receiving a multiplexed signal contain-ing a television signal as a main signal and a multiplex signal separated into a first multiplex signal and a second multiplex signal, wherein said main signal is time-multiplexed with said second multiplex signal to form a time-multiplexed main signal which amplitude-modulates a first carrier to form a first signal, and wherein said first multiplex signal amplitude-modulates a second carrier having the same frequency as said first carrier and being different in phase by 90 degrees from said first carrier and is then passed through an inverse Nyquist filter to form a second signal, said first and second signals being added to each other to form said multiplexed signal, said apparatus comprising:
    a Nyquist filter for filtering said multiplexed signal;
    a filtering means for filtering said multiplexed signal in order to eliminate crosstalk distortion of said multiplex signal by said main signal;
    a carrier regenerating means for regenerating said first carrier from said multiplexed signal;

    a first signal detecting means for detecting said first signal from said multiplexed signal passed through said Nyquist filter by synchronous detection using said regenerat-ing first carrier;
    a phase shifting means for shifting the phase of said regenerated first carrier by 90 degrees to obtain said second carrier;
    a first multiplex signal detecting means for detecting said first multiplex signal from said multiplexed signal passed through said filtering means by synchronous detection using said second carrier from said phase shifting means;
    and a time-demultiplexing means for time-demultiplexing said first signal into said main signal and said second multiplex signal;
    a signal composing means for composing said second multiplex signal and said first multiplex signal to obtain said multiplex signal.
  5. 5. An apparatus according to claim 4, wherein said multiplexed signal to be received by said apparatus contains a discriminating signal for identifying said multiplex signal in a vertical blanking interval, and wherein said apparatus further comprises a means for extracting said discriminating signal, a selecting means for selecting the main and multiplex signal, and a means for controlling said selecting means according to said discriminating signal.
  6. 6. A multiplex signal processing apparatus in a television signal transmitting and receiving system, comprising at a transmitting side:

    a main signal generating means for generating a televi-sion signal as a main signal;
    a multiplex signal generating means for generating a multiplex signal;
    a signal separating means for separating the multiplex signal into a first multiplex signal and a second multiplex signal;
    a time-multiplexing means for time-multiplexing said second multiplex signal and said main signal to obtain a time-multiplexed main signal;
    a carrier generating means for generating a first carrier;
    a first amplitude-modulating means for amplitude-modulating said carrier by said time-multiplexed main signal to obtain a first vestigial side band, amplitude-modulated signal;
    a phase shifting means for shifting the phase of said first carrier by 90 degrees to obtain a second carrier;
    a second amplitude-modulating means for amplitude-modulating said second carrier by said first multiplex signal to obtain a double side band, amplitude-modulated signal;
    an inverse Nyquist filter having a Nyquist characteris-tic for filtering said double side band, amplitude-modulated signal to obtain a second vestigial side band, amplitude-modulated signal;
    an adding means for adding said first and second vestigial side band, amplitude-modulated signals to obtain a multiplexed signal; and a transmitting means for transmitting said multiplexed signal, and at a receiving side:

    a Nyquist filter for filtering a received multiplexed signal;
    a filtering means for filtering said received multiplexed signal to eliminate crosstalk distortion of said multiplex signal by said main signal;
    a carrier regenerating means for regenerating said first carrier from said received multiplexed signal;
    a main signal detecting means for detecting said time-multiplexed main signal from said multiplexed signal passed through said Nyquist filter by synchronous detection using said regenerated first carrier;
    a phase shifting means for shifting the phase of said regenerated first carrier by 90 degrees to obtain said second carrier;
    a first multiplex signal detecting means for detecting said first multiplex signal from said multiplexed signal passed through said filtering means by synchronous detection using said second carrier from said phase shifting means;
    a time-demultiplexing means for time-demultiplexing said time-multiplexed main signal into said main signal and said second multiplex signal; and a signal composing means for composing said second multiplex signal and said first multiplex signal to obtain said multiplex signal.
  7. 7. An apparatus according to claim 6, wherein frequency characteristics of said inverse Nyquist filter and said Nyquist filter are substantially symmetrical to each other with respect to the frequency of said first carrier.
  8. 8. An apparatus according to claim 6, further comprising, at the transmitting side, a means for generating a discrimi-nating signal for identifying said multiplex signal, and a means for superposing said discriminating signal in a vertical blanking interval of said multiplex signal, and, at the receiving side, a means for extracting said discriminat-ing signal from the received multiplexed signal, a selection means for selecting said main and multiplex signals, and a means for controlling said selection means according to the extracted discriminating signal.
  9. 9. An apparatus for transmitting a wide aspect ratio television signal corresponding to an image displayed on a television screen having a wider aspect ratio than 4:3, comprising:
    a first time-axis expanding means for expanding on a time-axis a first part of said wide aspect ratio television signal corresponding to the aspect ratio of 4:3 to obtain a first television signal;
    a second time-axis expanding means for expanding parts other than the first part of said wide aspect ratio televi-sion signal to obtain a second television signal;
    a carrier generating means for generating first and second carriers which are equal in frequency and which differ in phase by 90 degrees from each other;
    a signal separating means for separating said second television signal into first and second multiplex television signals;
    a scrambling means for scrambling said second multiplex television signal;
    a time-multiplexing means for time multiplexing said first television signal and said second multiplex television signal to obtain a main television signal;
    a first amplitude-modulating means for amplitude-modulating said first carrier by said main television signal to obtain a first vestigial side band, amplitude-modulated television signal;
    a second amplitude-modulating means for amplitude-modulating said second carrier by said first multiplex television signal to obtain a double side band, amplitude-modulated television signal;
    an inverse Nyquist filter having a Nyquist characteris-tic for filtering said double side band, amplitude-modulated television signal to obtain a second vestigial side band, amplitude-modulated television signal;
    an adding means for adding said first and second vestigial side band, amplitude-modulated television signals to obtain a multiplexed television signal; and a means for transmitting said multiplexed television signal.
  10. 10. An apparatus according to claim 9, wherein said scrambling means comprises:
    a signal buffering means for exchanging line by line of said second multiplex television signal;
    a timing generator for controlling said buffering means; and a superposing means for superposing on the scrambled signal a control signal for descrambling at the reception side.
  11. 11. An apparatus according to claim 9, wherein said scrambling means comprises:
    a signal buffering means for exchanging left half and right half lines of said second multiplex television signal;
    a timing generator for controlling said buffering means; and a superposing means for superposing on the scrambled signal a control signal for descrambling at the reception side.
  12. 12. An apparatus according to claim 9, wherein said scrambling means comprises:
    a signal buffering means for exchanging polarity of said multiplex television signal line by line;
    a timing generator for controlling said buffering means; and a superposing means for superposing on the scrambled signal a control signal for descrambling at the reception side.
  13. 13. An apparatus for receiving the multiplexed television signal transmitted from the apparatus as claimed in claim 9, comprising:
    a means for receiving said multiplexed television signal;
    a Nyquist filter for filtering said received multiplexed television signal;
    a filtering means for filtering said multiplexed television signal passed through said Nyquist filter to eliminate crosstalk distortion of said second television signal by said first television signal;
    a carrier regenerating means for regenerating first and second carriers from said multiplexed television signal which are equal in frequency and which differ in phase by 90 degrees from each other;
    a first detecting means for detecting said main televi-sion signal from said multiplexed television signal passed through said Nyquist filter by using said regenerated first carrier;
    a second detecting means for detecting said first multiplex television signal from said multiplexed television signal passed through said filtering means by using said regenerated second carrier;
    a time-demultiplexing means for time-demultiplexing the main television signal into said first television signal and said second multiplex television signal;
    a descrambling means for descrambling said second multiplex television signal;
    a signal composing means for composing said first multiplex television signal and said second multiplex television signal to obtain said second television signal;
    and a means for composing said wide aspect ratio television signal from said first television signal and said second television signal.
  14. 14. An apparatus for transmitting a wide aspect ratio television signal corresponding to an image displayed on a television screen having a wider aspect ratio than 4:3, comprising:
    a first time-axis expanding means for expanding on time-axis a first part of said wide aspect ratio television signal corresponding to the aspect ratio of 4:3 to obtain a first television signal;
    a second time-axis expanding means for expanding parts other than the first part of said wide aspect ratio televi-sion signal to obtain a second television signal;
    a carrier generating means for generating first and second carriers which are equal in frequency and which differ in phase by 90 degrees from each other;
    a signal separating means for separating said second television signal into first and second multiplex television signals;
    a time-multiplexing means for time-multiplexing said first television signal and said second multiplex television signal to obtain a main television signal;
    a first amplitude-modulating means for amplitude-modulating said first carrier by said main television signal to obtain a first vestigial side band, amplitude-modulated television signal;
    a second amplitude-modulating means for amplitude-modulating said second carrier by said first multiplex television signal to obtain a first double side band, amplitude-modulated television signal;
    a third amplitude-modulating means for amplitude-modulating said second carrier by said first multiplex television signal to obtain a second double side band, amplitude-modulated television signal;
    a signal selecting means for selecting said first double side band, amplitude-modulated television signal and said second double side band, amplitude-modulated television signal to obtain a double side band signal;
    an inverse Nyquist filter having a Nyquist characteris-tic for filtering said double side band signal to obtain a second vestigial side band, amplitude-modulated television signal; and an adding means for adding said first and second vestigial side band, amplitude-modulated television signals to obtain a multiplexed television signal; and a means for transmitting said multiplexed television signal.
  15. 15. An apparatus for receiving the multiplexed television signal transmitted from the apparatus as claimed in claim 14, comprising:
    a means for receiving said multiplexed television signal;
    a Nyquist filter for filtering said received multiplexed television signal;
    a filtering means for filtering said multiplexed television signal passed through said Nyquist filter to eliminate distortion of said second televisions signal by said first television signal;
    a carrier regenerating means for regenerating first and second carriers from said multiplexed television signal which are equal in frequency and which differ in phase by 90 degrees from each other;
    a first detecting means for detecting said main televi-sion signal from said multiplexed television signal passed through said Nyquist filter by using said regenerated first carrier;
    a second detecting means for detecting from said multiplexed television signal passed through said filter means said first multiplex television signal modulated by said second amplitude-modulating means by using said regen-erated second carrier;
    a third detecting means for detecting from said multi-plexed television signal passed through said filtering means said first multiplex television signal modulated by said third amplitude-modulating means by using said regenerated second carrier;
    a signal selecting means for selecting said first multiplex television signal from outputs of said second and third detecting means;

    a time-demultiplexing means for time-demultiplexing said main television signal into said first television signal and said second multiplex television signal;
    a signal composing means for composing said first multiplex television signal and said second multiplex television signal to obtain said second television signal;
    and a means for composing said side aspect ratio television signal from said first television signal and said second television signal.
  16. 16. An apparatus for transmitting a wide aspect ratio television signal corresponding to an image displayed on a television screen having a wider aspect ratio than 4:3, comprising:
    a first time-axis expanding means for expanding in time-axis a first part of said wide aspect ratio television signal corresponding to the aspect ratio of 4:3 to obtain a first television signal;
    a second time-axis expanding means for expanding a second part, consisting of parts other than the first part, of said wide aspect ratio television signal to obtain a second television signal;
    a multiplexing means for multiplexing said first and second television signals in a frequency domain to obtain a multiplexed television signal; and a means for transmitting said multiplexed television signal;
    wherein said multiplexing means comprises:
    a carrier generating means for generating first and second carriers which are equal in frequency and which differ in phase by 90 degrees from each other;

    a signal separating means for separating said second television signal into first and second multiplex television signals;
    a time-multiplexing means for time-multiplexing said first television signal and said second multiplex signal to obtain a main television signal;
    a first amplitude-modulating means for amplitude-modulating said first carrier by said main television signal to obtain a first vestigial side band, ampltidue-modulated television signal;
    a second amplitude-modulating means for amplitude-modulating said second carrier by said first multiplex television signal to obtain a double side band, amplitude-modulated television signal;
    an inverse Nyquist filter having a Nyquist characteristic for filtering said double side band, amplitude-modulated television signal to obtain a second vestigial side band, amplitude-modulated television signal;
    and an adding means for adding said first and second vestigial side band, amplitude-modulated television signals to obtain said multiplexed television signal.
  17. 17. A television apparatus for transmitting and receiving a wide aspect ratio television signal, said apparatus including:
    an apparatus for transmitting a wide aspect ratio television signal corresponding to an image displayed on a television screen having a wider aspect ratio than 4:3, comprising:
    a first time-axis expanding means for expanding in time-axis a first part of said wide aspect ratio television signal corresponding to the aspect ratio of 4:3 to obtain a first television signal;
    a second time-axis expanding means for expanding a second part, consisting of parts other than the first part, of said wide aspect ratio television signal to obtain a second television signal;
    a multiplexing means for multiplexing said first and second television signals in a frequency domain to obtain a multiplexed television signal; and a means for transmitting said multiplexed television signal;
    and further including an apparatus for receiving the multiplexed television signal transmitted from the apparatus comprising:
    a means for receiving said multiplexed television signal;
    a signal separating means for separating the received multiplexed television signal into said first and second television signals;
    a first time-axis compressing means for compressing on a time-axis said first television signal to obtain said first part of said wide aspect ratio television signal;
    a second time-axis compressing means for compressing on a time-axis said second television signal to obtain said second part of said wide aspect ratio television signal; and a means for composing said wide aspect ratio television signal from the first and second parts;
    wherein said signal separating means comprises:
    a Nyquist filter for filtering said received multiplexed television signal;
    a filtering means for filtering said multiplexed television signal passed through said Nyquist filter to eliminate crosstalk distortion of said second television signal by said first television signal;
    a carrier regenerating means for regenerating first and second carriers from said received multiplexed television signal which are equal in frequency and which differ in phase by 90 degrees from each other;
    a first detecting means for detecting said main television signal from said multiplexed television signal passed through said Nyquist filter by using said regenerated first carrier;
    a second detecting means for detecting said first multiplex television signal from said multiplexed television signal passed through said filtering means by using said regenerated second carrier;
    a time-demultiplexing means for time-demultiplexing the main television signal into said first television signal and said second multiplex television signal;
    a signal composing means for composing said first multiplex signal and said second multiplex television signal to obtain said second television signal.
CA000562168A 1987-03-27 1988-03-23 Multiplex tv signal processing apparatus Expired - Fee Related CA1314620C (en)

Applications Claiming Priority (7)

Application Number Priority Date Filing Date Title
JP62074709A JPS63240279A (en) 1987-03-27 1987-03-27 Television signal processing method
JP62-74713/1987 1987-03-27
JP62074713A JPS63240282A (en) 1987-03-27 1987-03-27 Television signal receiver
JP62-74709/1987 1987-03-27
JP62-182523/1987 1987-07-22
JP62182523A JPS6425685A (en) 1987-07-22 1987-07-22 Transmission method for high-definition television signal
JP62-190703/1987 1987-07-30

Publications (1)

Publication Number Publication Date
CA1314620C true CA1314620C (en) 1993-03-16

Family

ID=27301593

Family Applications (1)

Application Number Title Priority Date Filing Date
CA000562168A Expired - Fee Related CA1314620C (en) 1987-03-27 1988-03-23 Multiplex tv signal processing apparatus

Country Status (1)

Country Link
CA (1) CA1314620C (en)

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