JPH01503591A - Method and apparatus for demodulating color television chromaticity signals - Google Patents

Abstract

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

Description

[Detailed description of the invention] Method and device for demodulating color television chromaticity signals This invention relates to composite color television signals, particularly television signals in NTSC format. The present invention relates to a method and apparatus for demodulating a standard single channel chrominance signal. TSC color television signal, broadband high definition wide aspect ratio color television signal NTSC-compatible 2-channel high-definition signal, and perhaps most importantly, It is applicable to narrow and wide aspect ratio color television signals.

Main butt raw blue In the latter system (e.g. referred to as 16:9, or 51/3:3) A high-definition wide aspect ratio single channel signal (such as inter image signal) and enhancement signal signals). The central image signal is the first channel in standard NTSC format. and received by a standard NTSC television receiver. produces a central image with an aspect ratio of 4:3.

The augmented signal is transmitted via the second channel. The enhanced signal is the side panel image (si de panel image), which includes the original image signal along with the central image signal. Play wide aspect ratio images.

The augmented signal also captures additional information in the central image that cannot be accommodated by the standard NTSC signal. carrying. This additional or augmented information is suitably combined with the NTSC central image signal. When combined, high definition is restored; this is because the center image signal is converted to a standard NTSC signal. Additional video/audio augmentation information that would have been “lost” if The information can be conveyed by an amplified signal on the second channel. 2 channels like that The NTSC compatible system is disclosed in U.S. Patent No. 4,694,338 2-100゜236).

Excellent reproduction of all high-definition wide aspect ratio images transmitted by two-channel systems receive both the first and second channel signals and combine them together in order to Stitch back properly to create a stitch. It is necessary to have a receiver that is invisible to the observer.

This means that the phase difference between the first channel signal and the second channel signal is compensated for and Black level, white level and chromaticity (hue and saturation) are adjusted for both channel signals. are reproduced equally, so any brightness, contrast, hue, or saturation These changes can be made by converting the original high-definition wide-aspect ratio image into two signals (separating them into two separate signals). to transmit over various channels and play them on the receiver's display device. It requires that it not be introduced by the process of decomposition (recombination).

Main Uni Kasamoto □ The present invention allows high-definition signals to be on) to give a training signal The chromaticity is resolved and transmitted via two separate channels, and the chromaticity is The problem of appropriately recombining the two signals generated when used with new methods of demodulation It solves some of the problems. The training signal is a signal within the vertical blanking interval. Preferably sent during line time or a portion thereof. Delicious. The training signal is the chromaticity signal of both the central image signal and the augmented signal. It is possible to establish and maintain a true phase reference for demodulating. Trainee ing signals are transmitted via both channels.

color between the signal source and the final receiver (ultia + ate receiver) Burst and sync signals are often changed, intentionally or unintentionally. This is well known. The source signal is for later broadcast, and the coaxial cable , satellite links, and cable television headend equipment. This occurs when the data is recorded and played back during its passage through the transmission system. obtain. If the signal transmission system does not have a flat frequency response and therefore If you want to introduce a gain change (usually a loss) that differs from the color carrier frequency at the frequency , distortion would also be introduced, which would create color saturation errors at the receiver. Furthermore, the modulation index (modulation 1ndex), demodulator Due to variations in tolerances, analog component tolerances, and other factors, center signal and panel The signal will not have reasonable gain or the correct black level.

These fluctuations are an error when viewing the new image via a standard NTSC signal. - is usually undesirable because it is uniform over the entire displayed image. isn't it. However, when considering the two-channel system mentioned above, the central image signal The saturation (phase and amplitude), gain, and black level effects associated with each of the augmented signals. Errors may exist, and images displayed without proper correction of these errors will be unacceptable. Variations in image characteristics between the center image and the panel images, which would not be included, are particularly important. That would be significant and troublesome.

The burst phase is shifted to give correct color reproduction at the final receiver. A signal is transmitted through a channel that does not have a flat or flat frequency response. Vertical interval standard (VIR: vertical 1nterv) The training signal of the present invention is V has some form in common with IP, but provides more useful information to the receiver. It is configured so that A system using the method and apparatus of the present invention avoids the above-mentioned errors. compensation and can operate without further reference to the NTSC color burst, thereby Incidental information is sent during the time otherwise occupied by the color burst. I am willing to accept and tolerate each and every one of them.

The demodulation according to the present invention involves sampling each signal, namely the central image signal and the augmented signal. Achieved through digitalization.

Each digitized signal is then modified for channel attenuation and the chroma and luminance signals. undergoes separation processing. The chroma signal is continuously sampled to produce the demodulated output. It is demodulated by algebraically adding the values of

4 dishes, 2 servings, 5 dishes FIG. 1a shows how the training signal of the present invention is adapted to the NT 1 is an illustration of a portion of a waveform of an SC television signal, Figure 1b switches the state of every other horizontal sync pulse and shows it as H/2. FIG. 1c shows further details of the training signal of the present invention. This is a detailed example, Figure 2a shows the sample clock signal, counter state, and training gate signal. 1 is a detailed illustration of a portion of a training signal of the present invention showing its relationship to signals; Figure 2b is the sample clock signal, and Figure 2c illustrates the state of the counter. Figure 2d illustrates the training gate signal of the present invention; FIG. 3 is a block diagram of functional components of a two-channel receiver according to the present invention; FIG. 4 is a block diagram showing the embodiment of the saturation demodulator of FIG. 3 in more detail; Figure 5 is a graph showing the gain versus frequency characteristics of the transmitted signal and the same signal at the receiver. It's rough, Figure 6 shows the relationship between the random value of the chromaticity signal, the sampling axis, and 1 and Q. FIG.

A deceitful amount of deceit The present invention provides a 2-channel high-definition widescreen compatible with standard NTSC television signals. This will be explained in the context of an aspect ratio television system, i.e. a two-channel One of the signals (center image signal) can be viewed on a standard NTSC television receiver. , whereas the original high-definition wide aspect ratio image receives both the central image signal and the augmented signal. can be viewed on a high-definition wide aspect ratio two-channel receiver.

In the system described above, the generated signal is High precision (e.g. 500 horizontal lines, 500 vertical lines) signal. U.S. Patent No. 4,694,338 (Patent Application No. 1983) -100,236), the generated signal consists of two signals, viz. That is, it is decomposed into a central image signal and an enhanced signal. These two signals are then combined into two standards transmitted via a broadcast or cable channel to the final receiver; The transmitter is a standard single channel NTSC receiver or a high definition wide aspect This disclosure will primarily deal with the latter. .

Referring to Figure 1a, a waveform representing a portion of a standard NTSC television signal is shown. has been done. A detailed display of NTSC and other standards for television broadcast signals is available at Benson's Television Engineering Handbook (Te levisionEngineeringHandbook), McGrawhi McGraw II Inc., 1986. Vertical block During the ranking interval 21, a number of equalization pulses are transmitted, followed by a vertical synchronization signal. This is followed by a post equalizing pulse.

Between vertical blanking intervals followed by several scan lines that carry no image information Several scan lines contain telex data, closing title data (clos ed captioning data)+VOR, etc., or saved for.

See, for example, U.S. Pat. No. 4,092,674, especially FIG. 2 thereof.

There are still some lines available for new use.

The present invention applies these lines, such as line 18, to the training signal. I am using one of the.

The training signal of the present invention consists of several cycles (e.g. a color subcarrier signal fsc of 50), which has a black reference level (bl ack reference level) 23 and white reference level 24 precede.

The training signal is shown in more detail in Figure 1c and also in more detail in Figure 2a. The black reference level 23 and the white reference level 24 and several cycles of counters are shown in detail. 3. A subcarrier frequency rsc is illustrated as an example. rsc in training signal For convenience, the phase of is chosen to be equal to 0 degrees with respect to the Q-axis or the I-axis. but This is not a requirement and a mathematical description of the demodulation method used by the invention is provided in this article. This condition will therefore be assumed to exist for explanatory purposes.

Apart from the number of color subcarrier cycles, the subcarrier amplitude and phase and The training signal differs from the standard NTSC signal because the specific white level is different. ing. These differences will be explained later, when the wide aspect ratio source image is and panel video signals, the encoder uses digital processing. Assuming, if this training signal is digitally inserted into the encoder It is important to note that the best results are obtained if

This is due to the alignment-to-drift Q typically associated with standard VIR and WIT signal insertion techniques. Let's remove (alignment and drift problem) .

At the receiver, both signals are sampled at 910fh=4fsc. Second Figure b represents the signal generated by a sample clock running at this frequency. There is. The frequency of the sample clock is one horizontal sync pulse of the received channel. derived from. Sample clock signal 1j repeats and counts 0.1゜2.3 It is used as an input to a 4-state counter. The counter state of the counter is the second It is shown in figure c.

Now looking at Figure 3, we can see that it receives the center signal and the augmented signal and converts them back to the original high-definition wide signal. A block of a portion of a two-channel receiver that recombines to display an aspect ratio image. A diagram is shown.

The tuner 31 automatically converts the two-channel signal to the baseband signal by 32. A/D converters 35 and 3 via dynamic gain side 41 (AGC) circuits 33 and 34, respectively. 6. Quantization is 9-bit linear, with 512 possibilities for each sample. 8-bit quantization giving 0, typically 256 possible values. is considered sufficient for digitizing color television signals. but , since the AGC operation allows fluctuations of up to 6 db, it is possible to increase the quantization to 9 bits. It was decided. Theoretically, if the level of quantization is appropriate, the AGC function can It can be executed on processor 43.44 as described below. now we have been shown The company has chosen to continue using such AGC circuits.

As noted earlier, there will be some transmission delay time on each channel, the two It should be assumed that the delay times are not the same. Therefore, A/D converters 35 and 36 After being digitized by , the two-channel signal has an equalized delay or Or time base corrector (TBC: time base core-c) tor) 37 (this predicate can be used interchangeably) ), and this time base corrector receives both channel signals and early-to-arrive signal and thus at its output both signals, i.e. the center image signal of channel 1. and channel 2's augmented signal should be decomposed for signal formation into the original high-definition wide-aspect The components of the pitch ratio signal are made to have the same time relationship. Time base correction It is the only parameter that is corrected independently of microprocessor 55. all Other parameters are controlled by microprocessor 55.

Both digitized signals from A/D converters 35 and 36 are one line buffer. memory 58. The only line written to buffer memory 58 is This is a line containing training signals for each channel. Micro as shown The processor has integrated controls for hue, saturation, gain, and black level for both video signals. are combined. That is, it provides the necessary coefficients for the operation of these correction circuits. This is because they are fully responsible for the The training signal can be determined by appropriate analysis. contains enough information to allow these parameters to be normalized. In the current configuration , the training signal is located on line 18 of each field, and this field is indicated by the address counter 57 and the timing generator 48 is shown in FIG. 2d. Create a training gate signal at 59 as shown below, which is A write cycle of the buffer memory 58 is enabled. Similarly, microprop Processor 55 releases control of the bus so as not to inhibit write cycles. this Immediately following completion of the cycle, microprocessor 55 performs its analysis and A microprocessor is used to control the buffer memory 58 in order to provide the appropriate coefficients. The processor 55 takes one frame to analyze the sample before a new line is to be written. field time (16.33 microseconds). Approximately 9ms prog A program with a ram execution time was used.

Synchronous stopper (sync 5 tripper) 47 for the output of AGC 33 is connected, which detects the horizontal synchronization signal and detects the horizontal synchronization pulse repetition rate f, They are output to a phase loop timing circuit 48 running at 910 times . Zhou The wave number 910fh is equal to four times the color subcarrier frequency fsc. synchronization list The capper 47 and the phase-locked loop (PLL)/timing circuit 48 are connected to the A/D converter 3. 5.36 and another circuit to be described below to provide sampling pulses. It acts as a sample clock 49. As noted above, the phase-locked loop Timing circuit 48 also generates the training gate signal shown in Figure 2d. Ru. The synchronization stopper 47 receives the channel 1 signal as long as the operating channel includes a horizontal synchronization signal. Note that it operates from either the channel 2 signal or the channel 2 signal. 2 channels In an NTSC compatible system, the signal is compatible with an existing NTSC receiver. The central image channel signal needs to include a synchronization signal to be a central image channel. The synchronization is It may or may not be included in the augmented signal. Horizontal sync and color bars It is contemplated that the strike will be omitted from the augmented signal. In fact, horizontal blanking All standard NTSC information contained in the interval is removed from the augmented signal and these timers This makes the muslot available for transmitting other information.

The digitized and time-base equalized signal contains low frequency and color subcarriers. processors 43 and 44 which compensate for attenuation of the composite video signal at both frequencies; It is then processed.

Each composite video signal has its original gain vs. frequency characteristics over its associated bandpass characteristics. This compensation is performed in order to approximately restore it to . Limited bandwidth channels at lower frequencies further attenuates the transmitted signal at frequencies higher than , and the attenuation increases with frequency. It is well known that this is not uniform. This is illustrated in Figure 5, which shows T. If the source signal spans a relevant bandwidth (e.g. frequency F from near zero to above fSC) This shows that the gain G is almost constant. By R, at the receiver The gain G versus frequency F characteristic of the same received signal is shown. This general characteristic Present in both channels, but not exactly the same for both channels It seems so. Therefore, gain-versus-frequency compensation must be performed on each of the two channels. The low frequency attenuation is denoted by B and the attenuation at rsc is denoted by A. Ru. Determination of the required gain and offset correction factors will be explained below.

Processing of two digitized signals is 910fh = 4fsc sampling Runs at speed. This is the same signal used by A/D converters 35 and 36. From the sample clock (synchronous stripper 47 and PLL/timing circuit 48) This is achieved through the use of a strobe signal. To compensate for the attenuation of two transmission channels In addition, processors 43 and 44 also separate chromaticity and luminance. Here's how we the chroma and luminance signals are separated, or the luminance signal of either channel is Luminance is separated from chromaticity in processors 43 and 44 unless related to other processing of the signal. The only thing to note is that This means that each processor labeled Y Represented by the output.

The digitized chromaticity signals C(n) from processors 43 and 44 are used for chromaticity demodulation. chroma demodulators 53 and 54, respectively, with additional signals used to perform the new method. is input. For each demodulator 53 and 54, these additional signals are with a coefficient calculated by the state of the processor 55 and the 4-state counter (÷4) 56. There is. The counter 56 has a sample clock speed of 4fsc and its four states are 0.1.2 ．． Progress through 3. Microprocessor 55 records its status as previously indicated. Reads and writes from the buffer memory 58, and also from the PLL/timing circuit 48. The rscO number size of each training signal under the control of the training gate 59 sample kuru. The microprocessor 55 determines the coefficients supplied to the saturation demodulator. Utilize these samples along with data from ROM 60 for calculations.

RO? The accumulated data of I60 is the original form of the training signal inserted at the generation point. represents the formula.

Gain and offset corrections by processors 43 and 44 apply to each of the two received signals. It uses coefficients calculated individually.

The training signal should be at least 16 samples of white level and 16 samples of black level. should be processed on the selected line (this happens once per field). 32 cycles of subcarry J are considered. The noise component present in each sample All samples representing the same information are averaged together to suppress , and the averaged result is then taken to represent the value of that parameter.

The received white and black level analysis can be used for contrast and black level correction. will produce a result representing the low frequency gain and DC offset of the signal. these two The determination of the parameters is performed by solving a set of simultaneous equations. reception The resulting white level St, + and black level Sbl are S, I = B XWLr*y + DC3b, = B xBLre, + DC, where B is defined as Fig. 5 represents the low frequency gain (or attenuation) shown in , DC represents the DC offset, and WLrllf and BL, , were stored in lll0M 60 at the receiver. They are a white level reference value and a black level reference value. This form of training signal is Includes a black level 75 IRE and a black level 7.5 IRE, and the basics stored in ROM 60. The quasi-values represent these values normalized to an 8-bit video bus. signal to noise In order to obtain a signal-to-noise advantage, These values correspond to the standard 50 IRE and 7.5 IRE levels used for VIP signals. selected over the years. Therefore, the gain at low frequencies is and the DC offset is teeth DC"　Sw+-B　XWL--r It is. These results are calculated on each field and the results from the previous field. is averaged. The filtered result is the actual correction that occurs on the video sample. It is output to processors 43 and 44 including time signal processing circuits. Until now, evenly Weighted averaging was used, but IIR filtering gave better results. It seems to produce fruit.

Conventional methods of separating luminance and chromaticity or more sophisticated techniques can be used. Izu In both cases, the output after separation is the center and panel luma. and the saturation signal. The normalized luma signal can be recombined (stitched) and Due to its effects, stitching techniques are quite complex and are not covered here. No. 057.849, 1987, for reference. I would like to mention the application filed on June 2nd (Japanese Patent Application No. 130.472/1983). chroma signal combined Before being transmitted, they must first be demodulated. Demodulation used here The coefficients are dynamic and are provided by a microprocessor. It consists of a two-tap digital filter. Once the saturation signal is demodulated, They can be recombined as well as luma signals.

Now, looking at FIG. 4, a block diagram of each of the saturation demodulators 53 and 54 in FIG. 3 is shown. It is. The sample C(n) is applied to the first power 401 of the first multiplier 403; and to the first power 407 of the second multiplier 409 via one horizontal line time delay 405 is being applied. The microprocessor 55 of FIG. It is applied to the second human power 411 and 413 of the 2 multiplier 409, respectively. 1st multiplication The outputs 415 and 417 of the multiplier 403 and the second multiplier 409 are input to the adder 423, respectively. 419 and 421, respectively. The output 425 of the adder 423 is 2: 1 multiplexer 429 and the inverter 431. The second input 433 of the 2:1 multiplexer 429 is connected through the 2:1 multiplexer 429 . 2:1 The output 435 of the multiplexer 429 is 1:2 demultiplexer 439 human power 437 It is connected to the.

Outputs 441 and 443 of the 1:2 demultiplexer 439 respectively receive the l signal and the Q signal. supplying. The counter status signal from the four-state counter 56 of FIG. The inputs 445 and 447 of multiplexer 429 and 1=2 demultiplexer 439 Both are applied.

0 normal 4 consisting of a saturation demodulator, 2-tap filter and a demultiplexer 439 Due to the NTSC signal digitized by fSC, demodulation is performed only by the demultiplexer. However, this technique requires a sampling clock and a colorverse. Accurate phase relationship between (R-Y, B-Y demodulation 0 degrees, I.

Q demodulation (33 degrees) and the color burst is true to active color video. It requires that the phase reference be

In this system 2. Compensates for the possibility that the color burst is not a precise phase reference and to allow flexibility in the sampling clock phase, another method is used. Ta.

As shown in the vector diagram in Figure 6, each chromaticity sample includes an I component and a Q component. I'm here. Decomposition of 1 component and Q component from a single sample is performed using the sampling clock and This is not possible if the angle θ between the I and Q axes is not 0 degrees. However, if θ If known, the combination of an appropriate function of θ and neighboring samples S+, Sz is a vector Let's decompose into its I and Q components. Process the information contained in the training signal. By doing so, θ can be calculated, and therefore θ can be known. well-known Unlike the technique, this technique works if the color vector does not change with time. Accurate. This demodulation configuration also embodies saturation demodulation, since the multiplier This is because the coefficients can be normalized to provide gain compensation.

The derivation of the coefficients required for this technique will be explained below.

The chromaticity signal C can be expressed by a sampling frequency of 910fh and 4fsc. Ki, t is where Tα is the arbitrary value of the sampling clock for the subcarrier. represents the static phase of Therefore, the sampled value at the input to the demodulator is The chromaticity signal is In this regard, a hardware microprocessor 5 of the form shown in FIG. It can be restored from the additional input coefficient signal C(n) given by 5. triangle identity 2 Using this, it can be shown as follows.

C(-1)=A　C+1(-1)sinθ-Ω(-1)cosθ)n=-1C( +0)=A　C+1(0)cosθ+Ω(0)sinθ〕n=0C(+1)=A [-1 (1) sin θ + Ω (1) cos θ) n = 1C (+2) = A C-1 ( 2) cos θ - Ω (2) s i n θ] n = 2C (+3) = A [+H (3) sin θ - Ω (3) cos θ] n = 3C (+4) = A C + H (4) cos θ ten Ω(4) sin θ] When applied to the n=4 circuit (see Figure 4), the adder 423 The output will be ■Using the band limit characteristics of the signal and Q signal, I (n-1) = I(n) = I and Ω(n-1) = Ω(n) = Ω can be approximated. .

and by assignment C' (0) - [+1 (0) cos" θ + Ω (0) sin θ cos θ)" 　0(-1)sin"θ-Ω(-1)sinθcosθ〕={I C’ (1) = (-1 (1) cos θ sin θ + Ω (1) cos “θ) + (+H(0)cosθsinθ10Ω(0)sin”θ)=+■ C' (2) = [-I (2) cos" θ-Ω (2) sin θ cos θ, l +[I(1)sin”θ+Ω(1)sinθcosoθ]=|I C'(3)-[+1(3)cosinθ-Ω(3)cos”θ) +(- IC2) cosθsinθ−Ω(2)sin2θ〕=−ΩC’　(4)=[ +1(4)cos”θ+Ω(4)sinθcosθ)+(+H3)sin” 　θ−Ω(3) sin θcosθ〕−10h C' (5) = (-1 (5) cosin θ 10 Ω (5) cos” θ) 10 ( +1(4) cosθsinθ10Ω(4)sin”θ]=+Ω.

The resulting data stream is then inverted by inverter 431 and 1:2 demultiplexer according to the counter states as shown in Table 1 and Figure 2c. 439 and both are demultiplexed by 2f8.439. to 441, which is the speed of 1 data stream at 443 and Q data stream at 443. horizontal speed The relationship of the clock frequency to is such that this sequence itself It's like it's repeated. Processor 5 to calculate the appropriate coefficients 5 has knowledge of the phase of this sequence relative to the samples stored in the buffer. There must be. This leads to the generation of the H/2 signal as shown in Figure 1b. Therefore, it is achieved. The phase of this signal (“ 1" or "O") is also stored in the buffer memory 58. H/2 signal Also resets the 4-division counter 56 and the address counter 57 of the buffer memory 58. used to cut. This process ensures perfect phase alignment of the demodulator, and takes into account all arbitrary initial conditions.

0 No inversion, ■ Connect to output 1 No inversion, connected to Q output 2 With inversion, ■Connect to output 3 With inversion, connected to Q output This is done by analyzing the reference burst of the nuking signal and the associated phase of the H/2 signal.

The sampled reference burst present at the receiver and written to memory 5B is where A is the subcarrier frequency ω, the channel at C is the gain (or attenuation) of the channel, L is any DC component, and K is the original transmission is a constant representing the amplitude, and N(r+) is the noise. Maximize signal-to-noise In order to Selected by IRE.

After the training signals are written to memory 58, microprocessor 55 Read the H/2 phase associated with the sample and its line. sampling clock frequency is 4f,C, so every fourth sample (i.e., occurs at the same counter state) all samples) will have the same value except for noise components. Therefore, Ka All data values of the same counter state of the counter 56 are Averaged, a set of four values, i.e. 5o=L+AKcosθ=L+AKcosθ Counter status=OK value is constant And RO at the receiver? It is stored in I.

The coefficients can be obtained by solving the following equations.

L + AK cos θ - (L - AK cos θ) further increases the performance of this system Therefore, the results of C1 and C2 calculated in each field are calculated from the previous field. You can also filter by results. These filtered results are then fed into the multiplier Output.

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Claims (9)

[Claims] 1. A high-definition television signal is transmitted over two separate channels. A type of television transmission system that is split into two signals, one of which is at least one of which is modulated onto a color subcarrier to generate a chromaticity signal. 1 and a second color component signal, wherein said two signals are said high definition television. which are recombined at the receiver to produce a high-definition display according to the vision signal In, A training signal is inserted into the transmitter and as part of each of the above two signals. said receiver to demodulate and recombine said two signals. television transmission characterized in that it comprises means for utilizing a training signal of system. 2. If the above training signal has multiple cycles at the above color subcarrier frequencies, a color subcarrier having a predetermined phase relationship with the above color subcarrier. A television transmission system according to claim 1, characterized in that it comprises a carrier reference portion. stem. 3. The above training signal is a black level reference portion having a predetermined black level amplitude. , a white level reference portion having a predetermined white level amplitude. The television transmission system according to item 2. 4. The predetermined black level amplitude is substantially 7.5 IRE, and the predetermined white level amplitude is 4. Television transmission according to claim 3, characterized in that the width is substantially 75 IRE. trust system. 5. Using the above training signal to demodulate and recombine the above two signals The time base of the time base that the means in the receiver described above corrects the above two signals. corrector, and analyze the above training signal in each of the above two channels, and A microprocessor that controls the hue, saturation, gain, and black level of the two signals described below. 2. The television transmission system according to claim 1, further comprising: 6. The original form of the above training signal as the receiver is inserted into the above two signals 6. The method according to claim 5, further comprising memory means for storing data representing the formula. Television transmission system. 7. The above microprocessor outputs the above two signals for contrast and black level. Using the data above representing the original form of the training signal above to correct each of The television transmission system according to claim 6, characterized in that: 8. Adaptable to the television transmission system according to any one of claims 1 to 4. transmitter. 9. Adaptable to the television transmission system according to any one of claims 1 to 7. receiver.