JPH0257080A - Amplitude level adjusting device - Google Patents

Abstract

PURPOSE:To prevent picture quality from being deteriorated at a joint even with the synthesis of both pictures by detecting a difference of amplitude levels of two reference signals and applying level control so that the amplitude levels of two television signals are equal to each other according to the detected output. CONSTITUTION:A difference of amplitude level between a reference signal for center outputted from an NTSC decoder 42 and a reference signal for side outputted from a side information decoder 44 is detected. The error signal is fed to an integration circuit 41. The integration circuit 41 adds an input signal to a preceding data and supplies the result to a multiplication circuit 11 as an amplitude control signal. Thus, the amplitude level of a demodulation output from a reference signal S1 of a luminance signal Y is controlled. Through the repetition of the operation above, the amplitude level of the signal S1 is made coincident with the amplitude level of a flat pulse P. The amplitude level of an amplitude control signal for side color difference signals I, Q is made coincident with the amplitude level of the center color difference signals I, Q similarly.

Description

Detailed Description of the Invention [Purpose of the Invention (Industrial Application! f) This invention provides a television signal that is obtained by multiplexing a second television signal within the baseband of a first television signal. The present invention relates to a television signal receiving device for receiving television signals, and particularly to an amplitude level adjusting device for equalizing the amplitude levels of both television signals.

(Prior Art) The NTSC system, which is one of the color television broadcasting systems, can be said to be an excellent system that is compatible with black and white television broadcasting and has sufficient performance as a color television broadcasting system. This can be seen from the results of implementation in Japan, the United States, and other countries.

Incidentally, over its long history, the image quality of the NTSC system has been significantly improved since its initial implementation as a result of constant efforts by both the transmitting and receiving sides.

However, in the NTSC system, there is a desire for further improvement in image quality due to the recent spread of large screen displays.

IDT is a method for improving the image quality of the NTSC system.
V (Improved Definition T
There is a method called e1evision). This method aims to improve image quality by making full use of the transmitted NTSC color television signal (hereinafter referred to as NTSC signal) on the receiving side.

This IDTV could not be implemented under conventional analog technology, but has become possible due to recent advances in digital technology.

According to this IDTV, compared to the conventional analog system,
Image quality can be significantly improved.

However, since this IDTV is based on the NTSC system, the upper limit of image quality that can be improved is NTSC.
Limited by method standards. Here, the upper limit items for the system include (1) screen aspect ratio (2) horizontal resolution of 330 Tv lines.

The aspect ratio of (1) is currently 4:3, but it is known that users prefer ratios such as 523 or 6:3 (Broadcasting System published by Japan Broadcasting Publishing Association (Editor) (See page 80 of 2 Japan Broadcasting Corporation)).

In addition, the high-definition television broadcasting system (High Definition)
(Te1evision), 19:6
aspect ratio may be adopted (CCIRR
eport801-2).

Regarding the horizontal resolution (2), in the NTSC system, 4
．． Since it is specified as 2MHz, the limit is 330Tv. On the other hand, considering the number of effective scanning lines (480 lines), a vertical resolution of 450 TV lines is possible even when considering margins such as overscan. Therefore, at this stage, it is desired to improve the horizontal resolution in terms of horizontal and vertical balance.

As an example of a system that improves the above two items and maintains compatibility with current television receivers, for example, Josep
h L, LoCicero “A Compatible
le HlghDefinition television
sion 5yste IIl (SLSC) with
Chrominance and Aspect R
atio lnpuruvements″5WPTE
Journal, May 1985. This 5LSC method will be described below.

FIG. 9 shows a spectrum diagram of the 5LSC method.

In FIG. 9, signals of 0 to 4.2 MHz are signals for maintaining compatibility with current television receivers. The 4.9-10.1 MHz signal is an additional signal used to expand the aspect ratio and the resolution of one luminance and one chromaticity. Therefore, in this 5LSC system, the signal for one station is transmitted using the band for two channels, and one channel basically transmits a signal similar to the current television broadcast signal, and the other channel transmits a signal that is basically similar to the current television broadcast signal. ,
It is designed to send additional signals to improve image quality.

According to such a configuration, channels received by current television receivers do not include additional signals, so
It is considered that there is high compatibility with respect to interference. However, 1
It is not efficient because it occupies two channels per station. Particularly in situations where channel allocation is near the limit, such as in Japan, implementation is expected to be difficult. In addition, when considering intra-station and inter-station transmission, current television broadcasting equipment is
Since it does not have a band that extends to 0 MHz, it is necessary to invest in all new equipment.

From the above, it is preferable to perform transmission within the band of one channel. Moreover, if additional signals can be multiplexed around the baseband of 4.2 MHz, compatibility with current television broadcast equipment such as video tape recorders and transmitters can be achieved.

As one method of multiplexing additional signals to the baseband near 4.2 MHz, T. Pukinuki et al.

“Extended Definition TV F
ully Compatible with Exist
ing 5 standards IEEE Tr, on
Coa+communication VOl, C0M-32
There is a method by No. 8, August 1984.

In the NTSC system, in the case of still images, this method uses the unused spectral region to add luminance daychill components (approximately 4 to 6
This is a MHz signal (hereinafter referred to as a luminance high frequency signal) that is used to multiplex YH. Here, the unused area is the first area in the vertical-time direction spectrum diagram of FIG.
．． The area of the third quadrant is used. Note that in the figure, C is a chromaticity signal.

By the way, this method is applicable only to still images and not to moving images. In the case of video, the spectrum spreads in the time direction and the original NTS
Since the C signal and the additional signal (luminance high frequency signal YH) overlap,
This is because it becomes impossible to separate both signals on the receiving side.

Since the brightness high frequency signal YH is effective for still images, even if the above method can transmit the additional signal only for still images, the objective of improving the resolution of still images can be achieved.

However, when transmitting a signal for enlarging the aspect ratio as an additional signal, the additional signal must be sent not only for still images but also for moving images. Therefore, the above-mentioned additional signal multiplexing method, which can transmit additional signals only for still images, cannot be used to transmit additional signals for expanding the aspect ratio.

In order to solve this problem, it may be possible to limit the motion component of the current NTSC signal, but if this is done, there is a high probability that unnatural motion will occur as a side effect, and existing television receivers Compatibility with

Furthermore, in the case of general natural images, the brightness high-frequency signal YH has a much lower level than the DC component, so even if it is multiplexed, there is little interference with current television receivers. On the other hand, when transmitting an additional signal for expanding the aspect ratio, it is necessary to transmit from a high-level DC component to a high-frequency component, and interference with the current NTSC signal becomes a problem. In order to solve this problem, it is possible to lower the transmission level of the additional signal, but if this is done, a new essential problem arises in that the signal-to-noise ratio during reception and reproduction deteriorates.

As mentioned above, in order to multiplex an additional signal to expand the aspect ratio within 4.2MHz of the baseband, it is necessary to: ■ Be able to transmit the additional signal regardless of whether it is a moving image or a still image ■ Current televisions It is necessary to satisfy the following conditions: there is little interference to the John receiver, and the signal-to-noise ratio (S/N ratio) during reception and reproduction of the additional signal can be maintained.

In addition, in this way, when transmitting an additional signal for expanding the aspect ratio in addition to the original NTSC signal to obtain a wide aspect screen, it is necessary to A condition is required that the image quality does not deteriorate at the seams.

(Problem to be solved by the invention) This invention was made to deal with the above problem (■).
For example, you can convert a television signal with an aspect ratio of 16:9 (or 5:3) to the original NTSC signal with an aspect ratio of 4:3.
Even when transmitting the signal and additional signal separately and combining them on the receiving side to reproduce a screen with an aspect ratio of 16:9 (or 5.3), it is important to note that the image quality will deteriorate at the joint between the images of both signals. The purpose is to provide a preventable device.

Specifically, the present invention provides an amplitude level adjustment device that prevents deterioration of image quality by equalizing the amplitude levels of both signals.

That is, in television broadcasting, there is a considerable amount of so-called linear distortion, such as disturbances in amplitude levels and disturbances in frequency characteristics on group delay characteristics, due to ghosts, deviations in frequency characteristics at relay stations, and the like.

In NTSC television broadcasting, the amplitude level of the color difference signal changes in various ways due to this linear distortion. For this reason, an NTSC television receiver is provided with an automatic color control circuit (so-called ACC circuit) to keep the amplitude level of the color difference signal constant.

By the way, when considering a television signal that is multiplexed with an additional signal for expanding the aspect ratio within the baseband of the original NTSC signal, in addition to the color difference signal of the original NTSC signal, the color difference signal of the additional signal also follows the above-mentioned linear pattern. Affected by distortion.

However, the ACC circuit can only keep the amplitude constant for the color difference signal of the original NTSC signal. Therefore, if a television signal is affected by linear distortion, a configuration that simply includes an ACC circuit will cause a difference in the amplitude level of the color difference signal of the NTSC signal and the color difference signal of the additional signal, and the color difference between the two images will be different. changes.

Note that this applies not only to color difference signals but also to luminance signals.

Therefore, in the present invention, the amplitude level of the original NTSC signal and the additional signal are made equal, so that the brightness and color do not change between the two images.

[Structure of the Invention] (Means for Solving the Problem) In order to achieve the above object, the present invention provides a television in which a second television signal is multiplexed within the baseband of the first television signal. During the vertical retrace period of the signal,
inserting a first reference signal having an amplitude level representing the amplitude level of the first television signal and a second reference signal having an amplitude level representing the amplitude level of the second television signal; 1. The difference in the amplitude level of the second reference signal is detected, and according to this detection output, the difference in the amplitude level of the first reference signal is detected. Level control is performed so that the amplitude levels of the second television signals are equal.

(Operation) According to the above configuration, the amplitude levels of the first television signal and the second television signal are made equal, so even if the two images are combined, the image quality will not deteriorate at the joint. .

(Embodiments) Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a circuit diagram showing the configuration of an embodiment of the present invention, and FIG. 2 is a diagram for explaining the operation of FIG. 1. Before explaining the configuration and operation of one embodiment, an example of a television signal transmission system to which the present invention is applied will be explained with reference to FIGS. 3 to 8.

FIG. 3 is a circuit diagram showing the configuration of the transmitting side.

In FIG. 3, 11 is an input terminal for color television signals. This signal has an aspect ratio of 16:9,
This is a sequential scanning (non-interlaced) signal with 525 scanning lines and a frame frequency of 60 Hz. In the drawings, such non-interlaced signals are expressed as 526/60.

This signal consists of a luminance signal represented by Y and color difference signals represented by I and Q.

The signal supplied to the input terminal 11 is sent to the screen division filter 1.
2. This screen division filter 12 divides the input signal into a portion corresponding to the center portion Fl of the screen F in FIG. 4 and a portion corresponding to the side portion F2. Here, the aspect ratio of the screen center portion Fl is set to 4:3.

Screen center portion Fl output from the screen division filter 12
The signal (hereinafter referred to as the center signal) is sent to the time expansion circuit 1.
3, and the time axis is expanded by 5/4 times. on the other hand,
The signal of the screen side portion F2 (hereinafter referred to as side signal) is expanded four times by the time expansion circuit 14. Figure 5 shows the state of time expansion. Of the effective horizontal walking period of 53 μs in terms of interlace, 42 μs is allocated to the screen center portion Fl, and 11 μs is allocated to the screen side portion F2. This relationship is (42+11):42X (3/4)-5:3,
Basically, it supports an aspect ratio of 5:3, but since it involves overscan in normal television receivers, assuming an overscan of about 6%, the aspect ratio is 16:3.
:9 aspect ratio can also be supported. onwards,
The description will be made using parameters based on the relationship shown in FIG. 5, but if you do not want to allow overscanning, you can slightly change the parameters described below.

The center signal is time-expanded by a factor of 5/4, resulting in a band of 0 to 10 MHz. Among the time-expanded center signals, the luminance signal Y is supplied to the luminance high frequency separation circuit 15. This brightness high frequency separation circuit 15 receives input signals from 8 to 8.
It is separated into a 10 MHz brightness high band signal YH and a 0 to 8 MHz brightness low band signal YL.

The brightness high frequency signal YH has its level suppressed by a level conversion circuit 16, and then is converted by a YH encoder 17 into a signal suitable for multiplexing. On the other hand, the luminance low-band signal YL undergoes pre-processing in the motion adaptive pre-processing circuit 18 to make it a signal suitable for multiplexing with the luminance high-band signal Y and the side signal, and then is supplied to the NTSC encoder 19. Ru. At this time, the spectrum of the luminance low-frequency component YL is limited to a region as shown in FIG. 6(a).

Among the center signals output from the time expansion circuit 13, the color difference signal 1. Q is NTSC with color difference band limiting filter 20
After being limited to a band that meets the standard, it is supplied to the NTSC encoder 19. And this NTSC encoder 1
9, the luminance low frequency signal YL is converted into an NTSC color television signal, and then the addition circuit 21
supplied to

On the other hand, the side signal is time-expanded four times by the time expansion circuit 14, and is made into a signal with a band of 2.2 MHz.

This time-expanded side signal is sent to the time-division color multiplexing circuit 22.
supplied to This time-division color multiplexing circuit 22 receives color difference signals 1. After band-limiting Q to 0.25 MHz, line sequential multiplexing is performed. Furthermore, by time-division multiplexing this line-sequential multiplexed signal and the luminance signal Y, the signal shown in FIG. 7 is obtained. In this case, the color difference signal I.

The amplitude of Q is set to 1.33 (110,75) times the normal value. This makes it possible to improve the S/N ratio on the receiving side.

The output of the time-division color multiplexing circuit 22 is outputted by the band compression circuit 23 at 1/30 [second] and 525/4 [in the vertical direction].
c, p, h], horizontally compressed to a band of 1-[MHzl. The level of this compressed output is suppressed by the level conversion circuit 24, and then converted by the side information encoder 25 into a signal suitable for multiplexing. This converted signal is, for example, an amplitude modulated signal using the compressed output as a modulation signal.

In this case, as the carrier wave, a signal having a frequency (for example, 3.07 MHz) that is an integral multiple of the horizontal synchronization frequency and whose phase is inverted for each field is used.

The spectrum of this converted signal is shown in FIG. 6(a).

It is located in the shaded area in FIG. 6(b), and is separated from the center signal in the horizontal and vertical spectral regions, as shown in FIG. 6(a).

The output of the side information encoder 25 is supplied to the adder circuit 21 and added to the output of the NTSC encoder 19.

This addition output is sent to the YH encoder 1 by the addition circuit 26.
It is added to the luminance high frequency signal YH output from 7. This addition output becomes the transmission signal.

FIG. 8 is a circuit diagram showing the configuration of the receiving side.

In FIG. 8, 41 is an input terminal to which a received signal is supplied. The received signal supplied to this input terminal 41 is converted into a luminance signal Y and a chromaticity signal 1 by an NTSC decoder 42.
．． It is decoded to Q. In this embodiment, since all the additional signals are included in the luminance region, the luminance signal output of the NTSC decoder 42 includes the additional signals. Therefore, the luminance signal output of the NTSC decoder 42 is supplied to both the YH decoder 43 and the side information decoder 44 and decoded. However, in FIG. 8, in order to simplify the explanation, the NTSC decoder 42, YH decoder 43, and side information decoder 44 are shown separately, and the center signal is processed while including the additional signal. Therefore, some interference remains in the additional signal. therefore,
In an actual television receiver, the signal separation circuits of the NTSC decoder 42, YI+ decoder 43, and side information decoder 44 operate as one, and each decoder 42, 43
．． 44 is configured so that unnecessary signals are not input.

The 4-5 MHz luminance high frequency signal YH decoded by the Y14 decoder 43 is the luminance low frequency signal YL of the center signal.
and are added by the adder circuit 45. With this, 0~5MH
A luminance signal Y having a band of z is obtained.

This luminance signal Y is compressed 415 times in time by the time compression circuit 46, so that it has a band of 0 to 6.25 MHz.

This time compressed signal is processed by a non-interlace conversion circuit 47 with a number of scanning lines of 525, a frame frequency of 60 Hz, and a band of 0 to 1.
3MHz (converted to No. a).

On the other hand, the side signal decoded by the side information decoder 44 is time-compressed by a factor of 1/4 by the time compression circuit 48. As a result, the number of scanning lines is 525 and the frame frequency is 60Hz.
, a signal in the band O~8 MHz is obtained.

This time-compressed side signal and the center signal output from the increment conversion circuit 47 are combined by a screen synthesis circuit 49 and converted into a signal having a large aspect ratio of 16:9. The luminance signal Y and color difference signals I and Q outputted from the screen synthesis circuit 49 are converted into R and G by an inverse matrix circuit 50.

The signal is converted into a B primary color signal and used for display.

Now, returning to FIG. 1, a level adjustment circuit according to an embodiment of the present invention will be explained.

The level adjustment circuit shown in FIG. 1 is provided at the input section of the screen synthesis circuit 49 shown in FIG. As mentioned above, the screen synthesis circuit 49 has the function of temporally switching between the center signal and the side signals to create a wide aspect ratio, but the level adjustment circuit adjusts the amplitude of the center signal as pre-processing for wide aspect ratio creation. By matching the amplitude level of the side signal to the level, a function is achieved to make the seam between the screen center portion Fl and the screen side portion F2 less noticeable.

Note that the level adjustment circuit is a multiplication circuit 11.5+.

91, subtraction circuit 21.61, 101, switch circuit 31
, 71, 111, and integrating circuits 41, 81, and 121; however, in order to make the explanation easier to understand, the figure also shows an NTSC decoder 42 and a side information decoder 44, which are signal supply sources for the level adjustment circuit. . However, the time compression circuits 46 and 48 and the non-interlaced conversion circuit 47 are omitted for convenience of explanation.

The level adjustment process roughly consists of the center reference signal output from the NTSC decoder 42 and the side information decoder 4.
The amplitude level of the side signal is controlled according to the detected output, and the amplitude level of the side signal is made to match the amplitude level of the center signal. Ru.

The reference signal is inserted into the vertical blanking period of a television signal obtained by multiplexing a side signal with a center signal.

This will be explained using FIG. 2.

FIG. 2 shows one horizontal scanning period within the vertical retrace period of the multiplex television signal. This horizontal scanning period includes a flat pulse P and signals 81 to S4 superimposed on this flat pulse P.

The flat pulse P is a reference signal having an amplitude level that indicates the amplitude level of the center luminance signal Y. This flat pulse P
The amplitude level of is set to 50IRE.

The signal Sl is a reference signal having an amplitude level that indicates the amplitude level of the side luminance signal Y. Specifically, the frequency is 3. 07 (= (6/7)' f sc ) [M
Hz] and the phase is 0[:radl], the carrier wave is amplitude-modulated with a signal having an amplitude level indicating the amplitude level of the side luminance signal Y, resulting in an amplitude-modulated signal. The amplitude level of this signal S1 is set to 50 to 100 IRE. This signal Sl is also transmitted for 6 to 7 cycles or more, and is also used as a signal indicating a reference phase when reproducing a carrier wave for decoding a side signal.

The signal S2 is the side color difference signal 1. A reference signal having an amplitude level indicative of the amplitude level of Q.

Specifically, the frequency is 3.07 (-(6/7)f s
c) A carrier wave with a phase of 0 [radl at MHz and a side color difference signal of 1. The amplitude modulated signal is amplitude-modulated with a signal having an amplitude level indicating the amplitude level of Q.

The signal S3 is the center color difference signal 1. A reference signal having an amplitude level indicative of the amplitude level of Q. Specifically, the frequency is fsc [MHz'l, and the center signal! The center color difference signal I is a reference signal having an amplitude level indicating a carrier wave having an axial phase.

It should be noted that the last signal S4 does not constitute a reference signal for level adjustment, but is applied to the screen center portion F1 and the screen side portion F2.
This signal indicates the switching position.

This signal S4 is a binary NRZ signal. Screen composition circuit 4
9 has an aspect ratio of 16: by connecting the level-adjusted center signal and side signal according to signal S4.
Combine 9 screens.

As mentioned above, the flat pulse P and the signal 5L-83 as the reference signal for amplitude level adjustment are the corresponding luminance signal Y and color difference signal 1. It has the same signal form as Q. Therefore, these flat pulses P and signals 5l-83 correspond to the luminance signal Y and color difference signal (2).

It receives approximately the same linear distortion as Q.

The level adjustment circuit in FIG. 1 includes a luminance signal Y1, a color difference signal I,
Each Q has an independent level adjustment section. Luminance signal Y
The level adjustment section for the multiplication circuit 11, subtraction circuit 21, switch circuit 31 . It is constituted by an integrating circuit 41. The level adjustment section for the color difference signal l includes a multiplication circuit 51, a subtraction circuit 61, a switch circuit 71 . It is constituted by an integrating circuit 81.

The level adjustment section for the color difference signal Q includes a multiplication circuit 91, a subtraction circuit 101, a switch circuit 111, and an integration circuit 121.

Since the level adjustment of each signal Y, I, and Q is the same, the level adjustment of the luminance signal Y will be mainly explained here.

One input terminal of the multiplication circuit 11 is supplied with the demodulated output of the signal S2 from the side information decoder 44. The other input terminal of this multiplier circuit 11 is supplied with an amplitude control signal which is an integral output of an integrating circuit 41 . The multiplication circuit 11 multiplies these two input signals and supplies the multiplication output to one input terminal of the subtraction circuit 21 . This subtraction circuit 2
A flat pulse P is supplied from the NTSC decoder 42 to the other input terminal of the NTSC decoder 42. The subtraction circuit 21 takes the difference between the amplitude levels of these two input signals and outputs it as an error signal. This error signal is supplied to an integrating circuit 41 via a switch circuit 31 that is controlled to be turned on during the period in which the error signal occurs. Integrating circuit 41 adds the input signal with previous data and supplies this to multiplication circuit 11 as an amplitude control signal. This controls the amplitude level of the demodulated output of the signal S1.

By repeating the above operation, a fitback is applied so that the error signal output from the subtraction circuit 21 becomes 0, and the amplitude level of the signal Sl is made to match the amplitude level of the flat pulse P. Therefore, after this, by outputting the side brightness signal Y from the side information decoder 44 and passing it through the multiplication circuit 11, it is possible to obtain the side brightness signal Y having the same amplitude level as the center brightness signal at the output terminal 61.

Amplitude control signals for side color difference signals I and Q are obtained in the same manner, and output terminals 62 and 63 receive center color difference signals I and Q.
Side color difference signal 1. having an amplitude level matched to the amplitude level of Q. Q is obtained.

According to this embodiment described in detail above, it is possible to match the brightness and color between the screen center portion Fl and the screen side portion F2, and it is possible to prevent image quality from deteriorating at the joint between the two.

This is because the difference between the reference signal for the center signal and the reference signal for the side signal is determined, and the gain of the side signal is controlled accordingly.

Further, the original brightness and color can be reproduced for both the screen center portion Fl and the screen side portion F2.

This is because the amplitude level of the center signal is used as a reference, and the amplitude level of the side signals is made to match this. In other words, since the center signal and its reference signal are NTSC signals, the original amplitude level can be reproduced using the automatic gain control circuit (AGC circuit) and ACC circuit normally provided in television receivers. Note that the side signal and its reference signal have a different format from the NTSC signal, so these AGC and ACC circuits cannot reproduce the original amplitude level.)
. Therefore, according to this embodiment in which the amplitude level of the side signal is controlled using this as a reference, the amplitude level of the side signal can also be reproduced to the original amplitude level, and in both the screen center portion Fl and the screen side portion F2. It is also possible to reproduce the original brightness and color.

Although one embodiment of the present invention has been described in detail above, the present invention is not limited to this embodiment.

For example, in the previous embodiment, a case has been described in which the levels of all of the luminance signal and the color difference signals 1 and Q are adjusted, but the level control of at least one of them may be performed.

In addition, in the previous embodiment, the case where the amplitude level of the side signal is made to match the amplitude level of the center signal was explained, but especially when there is no need to reproduce the original brightness or color, The amplitude levels of the center signals may be matched.

In addition, in the previous embodiment, the color difference signal is 1. Although the description has been given of the case where the television signal Q is handled, it is of course applicable to the case where the television signal R-Y, B-Y is handled. Although the case where a color television signal is handled has been described, the present invention is of course applicable to a case where a black and white television signal is handled.

Furthermore, the present invention is applicable not only to the multiplexing method of television signals as explained in FIG. 7, but also to a multiplexing method as explained in FIG. Of course.

Furthermore, it goes without saying that the present invention is applicable to purposes other than level adjustment of wide aspect television broadcasting systems.

It goes without saying that various other modifications can be made without departing from the gist of the invention.

[Effects of the Invention] As detailed above, according to the present invention, one of the two television signals obtained by splitting the screen is multiplexed with the other and transmitted, and the receiving side combines them to reproduce the original screen. In a television broadcasting system for playback, it is possible to prevent brightness and color from changing at the seams of screens, and it can contribute to obtaining a high-quality composite screen.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing the configuration of an embodiment of the present invention, and FIG.
3 is a circuit diagram showing the configuration of the transmission side of an example of a television broadcasting system to which the present invention is applied, and FIGS. 4 to 7 are diagrams for explaining the operation of FIG. 8 is a circuit diagram showing the configuration of the receiving side, and FIGS. 9 and 10 are diagrams for explaining the technical aspects to which this invention focuses. . 42...NTSC decoder, 44...Side information decoder, 61-63...Output terminal, 11.5191.
...Multiplication circuit, 21.61,101...Subtraction circuit, 3
1.71,111...Switch circuit, 41.81°1
21... Integral circuit. Applicant's agent Patent attorney Takehiko Suzue

Claims (6)

[Claims] (1) A second television signal containing a luminance signal is multiplexed within the baseband of a first television signal containing a luminance signal, and the first television signal A television in which a first reference signal having an amplitude level indicating the amplitude level of the luminance signal of the signal and a second reference signal having an amplitude level indicating the amplitude level of the luminance signal of the second television signal are inserted. A television signal receiving device for receiving a signal, comprising: difference detection means for detecting a difference between the first reference signal and the second reference signal; and a difference detection means for detecting a difference between the first reference signal and the second reference signal; 1. An amplitude level adjusting device comprising: level control means for performing level control so that the amplitude levels of the luminance signals included in the television are equal. (2) A second television signal containing a luminance signal and two color difference signals is multiplexed within the baseband of a first television signal containing a luminance signal and two color difference signals, and a vertical retrace line A first reference signal having an amplitude level indicative of the amplitude level of the luminance signal of the first television signal and a second reference signal having an amplitude level indicative of the amplitude level of the luminance signal of the second television signal within the period. A television signal receiving device that receives a television signal into which a reference signal is inserted, comprising: difference detection means for detecting a difference between the first reference signal and the second reference signal; An amplitude level adjusting device comprising: level control means for performing level control so that the amplitude levels of the luminance signals included in the first and second televisions are equal in accordance with the detection output. (3) A second television signal containing a luminance signal and two chrominance signals is multiplexed within the baseband of a first television signal containing a luminance signal and two chrominance signals, and a vertical retrace line The two color differences between the first reference signal and the second television signal having an amplitude level indicating the amplitude level of at least one of the two color difference signals of the first television signal within the period. In a television signal receiving device that receives a television signal into which a second reference signal having an amplitude level indicating the amplitude level of at least one color difference signal of the signal is inserted, the first reference signal and the second reference signal are inserted. and a difference detection means for detecting a difference from a reference signal of the first and second televisions, and level control is performed according to the detection output of the difference detection means so that the amplitude levels of the color difference signals of at least one of the first and second televisions are equal. 1. An amplitude level adjustment device comprising: level control means for controlling the amplitude level; (4) The first television signal is an NTSC color television signal, and the second television signal is a line-sequential multiplexing of the two color difference signals, and a time-division multiplexing of the luminance signal thereon. Claim 2 or 3, wherein the multiplexed signal is an amplitude modulated signal obtained by modulating a carrier wave having a frequency that is an integral multiple of the horizontal synchronization frequency and whose phase is inverted for each field. Amplitude level adjustment device as described in section. (5) The first reference signal is a flat pulse, and the second reference signal is amplitude modulated with a modulating signal having an amplitude level indicating the amplitude level of the luminance signal of the second television signal. 2. The amplitude level adjusting device according to claim 1, wherein the amplitude level adjusting device is a signal. (6) The first reference signal includes a flat pulse having an amplitude level indicative of the amplitude level of the luminance signal and an amplitude modulated signal whose modulation signal is a signal indicative of the amplitude level of at least one of the color difference signals. , the second reference signal is an amplitude modulated signal whose modulation signal is a signal having an amplitude level that indicates the amplitude level of the luminance signal and at least one of the color difference signals included in the second television signal; The amplitude level adjusting device according to claim 2 or 3, characterized in that: