KR940007159B1 - Ghost erasing standard signal production and transmitter-receiver device in tv and the method of erasing ghost - Google Patents

Abstract

The ghost cancelling reference (GCR) signal transmitting/receiving apparatus and ghost cancelling method in a television system comprises a GCR generating circuit for generating GCR signal having a first step, a superimposing circuit for superimposing the GCR signal to a vertical blanking interval of a television signal, a transmitting circuit for transmitting the television signal in which the GCR signal is superimposed, a receiving circuit for receiving the transmitted television signal, a GCR separating circuit for separating the GCR signal from the received television signal, a GCR processing circuit for generating a ghost cancelling control signal, and a ghost cancelling circuit for cancelling a ghost signal by the ghost cancelling control signal, thereby improving television picture quality.

Description

Generation of Ghost Elimination Reference Signals in Television Systems, Transceiver and Ghost Elimination Methods

1 is a schematic block diagram of a ghost cancellation reference signal generation and transmission / reception apparatus according to the present invention.

2 is a view of a ghost cancellation reference signal generation and transmission and reception apparatus according to the present invention. Detailed block diagram

3 is a detailed block diagram of the ghost cancellation reference signal generator shown in FIG. 1 and FIG.

4 and 5 are waveform diagrams of a ghost cancellation reference signal according to the present invention.

6 is an operation timing diagram of FIG.

The present invention relates to an apparatus and method for improving television picture quality, and more particularly to an apparatus and method for reducing or eliminating ghost images.

Ghost images, commonly referred to as " ghosts ", occur intermittently in the received television picture. Comparing the ghost and the television image generated by the signal received by the direct path, the ghost is generated by a time delay, attenuation of the original television signal, distortion, etc., and is received through a path other than the direct path. Here, the signal path other than the direct path refers to a multipath. In general, delay and attenuation can be positive or negative. Therefore, rather than the main signal. It is possible to have ghosts or pre-ghosts with larger amplitudes. In addition, the ghost signal variable may change with time.

Multipath can be broadly categorized into long distance multipath and short range multipath. Long distance multipath manifests itself as a dependent ghost phase located horizontally relative to the existing television phase, while short distance multipath affects the video high frequency. In some cases the effect of short-range multipath, accompanied by some loss of image information, is typically observed with a clear increase or decrease in image clarity. Attenuation of video high frequencies can lead to a clear image on the screen. Short-range multipath is typically associated with a cable distribution system and usually results from multiple echoes and termination mismatches called "mlcor-ghosts." Long-range multipath ghosts are typically While reduced by the cancellation scheme, the effect of short-range multipath is typically mitigated by waveform equalization, typically group-delay correction or peaking of the video high frequency response. .

The phenomenon of television ghosts has been mentioned in terms of improving picture quality by removing or reducing ghosts. For example, vo1. In "IEEE Transactions on Consumer Electronic". A note on "ATUTORIAL ON GHOST CANCELLING IN TELEVISION RECEIVERS," published by CE-25,2 / 79, W.Ciciora, et al., Pages 9-43. See also. Other solutions to the ghost problem are disclosed in US Pat. No. 4,896,2l3 to Kobo et al. 23 January 1990 and US Pat. No. 4,897,725 to Tanaka et al. 30 January 1990. .

Since the characteristics of the transmitted television signal were previously known, it is possible, at least in theory, to use such characteristics in ghost signal detection and cancellation systems. Nevertheless, various problems limit this approach. For example, it has been found that it is desirable to repeatedly transmit a reference signal located in a section of a television signal which is not currently used for video, and use this reference signal for detection and cancellation of a ghost signal. Typically a scan line at the vertical blanking interval (VBI) is used. Such a signal is referred to herein as a ghost canceling reference (hereinafter referred to as GCR) signal.

It has been suggested that useful test results or GCR signals can exhibit (sin x) / x waveforms properly. This waveform shows a relatively constant spectral energy density in the frequency band of interest. For example, the above mentioned oil. See W. Ciciora et al., Where the ghost position can be determined for waveform equalization to reduce the effects of ghost signal cancellation and short-range multipath.

The ghost cancellation device designed in U.S. Patent No. 4,896,213 mentioned above can reduce or eliminate ghost components caused by the distortion of the frequency-amplitude characteristic and the group delay distortion generated in the signal transmission path. The receiving system is disclosed. This is obtained by superimposing a digital signal on a television signal as a GCR signal. Therefore, a digital signal composed of a frame synchronizing signal, a clock synchronizing signal, and a data signal is generated as disclosed in US Patent No. 4,896,213 mentioned above. During the vertical blanking interval, this digital signal is superimposed on the television signal to be transmitted. The digital signal superimposed on the television signal at the end of reception is used as a reference signal in the apparatus which performs the correlated operation of the transmitted television signal to reduce the ghost phenomenon.

In the apparatus disclosed in US Pat. No. 4,897,725 mentioned above, the transmitted reference signal or GCR signal is also used. A dummy ghost signal is generated and used to cancel the ghost signal in the transmitted television signal. This is practically a BTA GCR signal proposed mainly for the nature of a signal with abundant high frequency spectrum energy content, and uses the signal having the above-described (sin x) / x waveform as the main reference signal or deghosting signal. The average of the pair-wise constant sigI1al paired is used to obtain the received reference waveform. The received waveform is Fourier transformed to provide a set of Fourier coefficients. Then to calculate the tap gain information for the de-ghosting filter variable, ie for the transversal filter, for the waveform equalization by the finite impulse response (FIR) and the de-ghosting filter with the infinite impulse response (IIR). The transformed reference waveform is then treated as a useful FFT of the intact GCR.

As can be expected, GCR signals are generally received with a ghost signal. Accordingly, the GCR signal itself becomes a ghosted signal. It is recognized here that the performance of the ghost cancellation system is mainly affected by the noise and the perturbation of the obtained GCR signal. It is also recognized that noise reduction and perturbation of the obtained GCR signal are desirable in increasing the accuracy of deghosting filter parameter derivation and reducing system complexity.

It is also recognized here that the step at the leading edge of the signal in the GCR signal is desirable to calculate the ghost position. As mentioned previously, the (sin x) / x waveform offers special advantages in GCR signals. The planar frequency spectrum of the (sin x) / x waveform provides waveform equalization as well as accurate calculation of filter parameters to attenuate multiple phase effects. Allows the calculation of. However, in addition to other high frequency components, the ripples characteristic of the sin x / x waveforms are typically attenuated in the received ghosted GCR signal, not only because of the multipath effect, but also because of the wrong direction of the actual common occurrence of Andena. . Under these conditions, the calculation of waveform equalization variables can be quite error-prone.

This problem is particularly evident when the (sin x) / x step is used in the rising edge of the pulse, as in the proposed BTA GCR signal, so the obvious benefit of using (sin x) / x waveforms is practically hardly realized. In an effort to alleviate this problem by further improving the signal-to-noise ratio, the average of the constant signal paired in the proposed BTA GCR signal is many. The use of a number of vertical blanking interval scan lines requires pairing, but The average of a constant signal is undesirable in view of the various comparable requirements for the vertical blanking interval scanning line over other signals.

Accordingly, an object of the present invention is to provide a GCR signal generation and transmission apparatus and a ghost cancellation method capable of efficiently erasing a ghost signal in a television system.

The GCR signal transmitting and receiving device according to the present invention includes a GCR signal generator for generating a GCR signal having a first step of 2T edges, and an overlapping circuit and a GCR signal signal superimposed on a vertical blanking interval of a television signal for transmitting the GCR signal. A transmission circuit for transmitting the superimposed television signal, a reception circuit for receiving the transmitted television signal, a GCR signal separator for separating the GCR signal from the received television signal, and processing the separated GCR signal to cancel the ghost signal. And a GCR signal processing circuit for generating a ghost erase control signal, and a ghost cancellation circuit for canceling the ghost signal by the ghost erase control signal from the received television signal. Here, the first step of the 2T type has a rising time of 250 ns between 10% and 90%, and has a frequency spectrum of 4 MHz. In practice, however, 1.2T or 1 5T steps can be used when 1.2T or 1.5T steps are optimally located in the bandwidth of the transmission medium. Thus, 2T steps are used in this sense as intended here.

In addition, the GCR signal generator according to the present invention generates a GCR signal further having a second step in the form of a trailing edge (sin x) / x.

In addition, the GCR signal generator according to the present invention generates a GCR signal having a relatively constant horizontal area between the first step and the second step.

In addition, the GCR signal generator according to the present invention simply changes the first step of the GCR signal from 0 IRE to 70 IRE in the form of 2T, and changes the second step of the GCR signal from 70 IRE to 0 IRE (sin x) /. The first step and the second step have a rising time and falling time of 250ns between 10% and 90%.

In addition, the GCR signal generator according to the present invention generates a gating pulse and a field identification signal based on a clock generator generated from a clock signal in synchronization with a synchronous signal of a video signal, and the synchronous signal and the clock signal. A gating pulse generator, a memory device for storing information defining a GCR signal, and a multiplexer for outputting information stored in the memory device as a GCR signal according to a gating pulse and a field identification signal are provided.

In addition, according to the present invention, a method for canceling ghost in a television signal includes a GCR signal generation process for generating a GCR signal having a first step of a 2T shape and a vertical blanking interval of a television signal for transmitting a GCR signal. A superimposition process of superimposition, a transmission process of transmitting a television signal superimposed with a GCR signal, a reception process of receiving a transmitted television signal, a GCR signal separation process of separating a GCR signal from a received televersion signal, and separation A GCR signal processing for generating a ghost erase control signal for processing the GCR signal to erase the ghost signal, and a ghost erase process for canceling the ghost signal by the ghost erase control signal from the received television signal.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a schematic block diagram of a GCR signal generation and transmission and reception apparatus according to the present invention. In FIG. 1, a television transmitter 2, such as a television walk transmitter, is connected to a transmission antenna 4 for transmitting a television signal. The GCR signal generator 6 is connected to the television transmitter 2 to supply the GCR signal. The television transmitter 2 supplies a video signal to the GCR signal generator 6 for use in generating a GCR signal as described later. The receiving antenna 8 is connected to the television receiver 10 and receives the signal transmitted by the transmitting antenna 4 and supplies it to the television receiver 10. The GCR signal separator 12 is connected to the television receiver 10 and receives a video signal from the television receiver 10 and separates the GCR signal from the video signal. The GCR signal separator 12 is also connected to a ghost cancellation circuit 14 connected to the television receiver 10. The ghost cancellation circuit 14 processes the GCR signal and supplies a ghost cancellation variable to the television receiver 10.

Referring to the operation of FIG. 1, the GCR signal generator 6 generates a GCR signal according to the present invention in synchronization with a video signal supplied from the television transmitter 2, and supplies it to the television transmitter 2, and the television transmitter 2 Is sent by The transmitted signal can reach the receiving antenna 8 via direct path and multipath. The received GCR signal is separated by the GCR signal separator 12 and supplied to the ghost cancellation circuit 14. The ghost signal is then erased in the television receiver 10 using the GCR signal.

2 is a view of a GCR signal generation and transmission and reception apparatus according to the present invention. As a detailed block diagram, the television transmitter 2 of FIG. 1 superimposes a GCR signal on a television signal obtained from a television signal source 3 for transmission by a transmission circuit 7 connected to a transmission antenna 4. The superimposed circuit 5 is shown. The GCR signal separated by the GCR signal separator 12 is supplied to the GCR signal processing circuit 16 connected to the ghost cancellation circuit 14 on the receiving side. have.

3 is a detailed block diagram of the GCR signal generator 6 shown in FIG. 1 and FIG. Referring to FIG. 3, the video signal supplied from the television signal source 3 of FIG. 2 is applied to the sync separator 18. As shown in FIG. The sync separator 18 separates the sync signal from the video signal and applies it to the clock generator 20 and the gating pulse generator 22. The clock generator 20 generates a clock signal in synchronization with the synchronization signal separated by the synchronization separator 18. The gating pulse generator 22 is connected to the multiplexer 30 to generate the first and second gating pulses and the field identification signal by the synchronization signal and the clock signal, and supplies them to the multiplexer 30. The synchronization signal input to the gating pulse generator 22 and the first and second gating pulses and the field identification signals outputted are as shown in FIG. The first, second, and low 13 PROMs (Programmable Read Only Memory) 24, 26, and 28 are connected to the gate pulse generator 22 and the multiplexer 30 and programmed according to the GCR signal variable according to the present invention, respectively. Stores information defining the signal. The first PROM 24 stores the horizontal sync pulse and the burst signal. The second PROM 26 is a GCR signal component having a first step of a 2T type that changes from 0 IRE to 70 IRE, a second step of (sin x) / x type that changes from 70 IRE to 0 IRE, and the first step and the first step. The signal of a certain level between two steps is stored. The third PROM 28 is optional for use in storing 0 IRE signals in the case of another embodiment of the present invention. The GCR signal will be described in more detail below. The multiplexer 30 inputs signal components from the first, second, and third PROMs 24, 26, and 28, and gates the GCR signal according to the first, second gating pillars and the field identification signal. Transfer to (2).

4 shows a waveform diagram of a GCR signal generated by the GCR signal generator 6 according to the present invention. For convenience, IRE units according to the IRE standard scale are used for waveform characteristics. The IRE unit is a linear scale for measuring the relative amplitudes of various components of a television signal. For example, Kay, published by McGraw-Hill Publishing, New York. See section 2l.41 of the Television Engeneering Handbook, 1986, published by K Blair Benson.

In FIG. 4 the time T is measured by starting from zero at the leading edge of the horizontal synchronizing pulse 300. That is, the time T is measured from the leading edge of the horizontal synchronous pulse 300. The horizontal synchronous pulse 300 usually follows the burst signal 302 on all scan lines of the vertical blanking interval. In this case, the burst signal 302 refers to a color or chroma burst signal. However, in the embodiment to be described later, the burst signal 302 is omitted. Reference numeral 400 denotes a signal consisting of a horizontal synchronous pulse 300 and a burst signal 302 stored in the first PROM 24, and reference numeral 402 denotes a first step of 2T type stored in the second PROM 26. A signal composed of a second step 306 of the form 304 and (sin x) / x, and a signal 308 having a constant level between the first step 304 and the second step 306 is shown. The maximum ghost section is the longest section in which ghost can be detected and erased. Therefore, if ghost occurs outside the maximum ghost section, the detection and cancellation cannot be performed.

According to an embodiment of the present invention, another feature of the GCR signal generated by the GCR signal generator 6 as shown in FIG. 4 is a 2T type step in which the first step 304 simply changes to 0 IRE, and the second step ( 306) is a (sin x) / x step that changes from 70 IRE to 0 IRE, and the rise and fall time is about 250ns between 10% and 90% of each of the first and second steps. The bandwidth of the integrated pulse (BW. Band Width) is 4.177377 MHz. In the illustrated embodiment, the beginning of the first step portion 304 is selected to be present at T = 33 μs.

As will be understood by one of ordinary skill in the art, the maximum de-ghosting range, i.e. the maximum multipath that can be handled without conflict with the aliasing form of the problem for the next horizontal scan period, is the persistence of the GCR signal. It is determined by the time and the remaining period in which the ghost signal can be found. In this embodiment, the chroma burst signal 302 is omitted to provide a maximum deghosting range of 25 μs or less.

Since the considered preghost is a relatively short duration and is typically 3 μs or less, it is not necessary that the GCR signals appear in pairs and appear constant, and the GCR signal is only one at vertical blanking intervals. It is limited to the scan lines of and repeats the same on all fields. Because of the limited requirements for vertical blanking intervals, GCR signals are easily accommodated in television signals.

For example, if it is not possible to omit the chroma burst signal due to the limitations of the transmitter, the GCR signal is modified as shown in FIG. In the waveforms shown in FIGS. 5 to 5a, the waveform of the first step 304 starts at about 30 s and only exists in the odd field. Is essentially the same as the waveform shown in FIG. The waveform shown in FIG. 5B is flattened at 0 IRE instead of the first step 304 and the second step 306 only on the vertical retrace interval of the even field following which the same chroma phase is obtained. In addition, reference numerals 300-308 and 400-402 in FIGS. 5A and 5B are the same as those in FIG. 4 described above, and reference numeral 404 is stored in the third PROM 26. Indicates the flat part of 0 IRE.

It will be apparent to one of ordinary skill in the art that in this case a de-ghosting range of 30 μs or less can be obtained by logarithmic subtraction of the GCR signal. It will also be understood by one of ordinary skill in the art that the generation of the signal may be reversed between the odd and even scan lines. Therefore, the first step 304 and the second step 306 may be arranged so as to appear only in the odd field of the television signal. The first step 304 also starts at 30 s after the start of the horizontal sync pulse. In the next even field where the same chroma phase is obtained, the GCR signal has a flat portion 404 of 0 IRE instead of the first step 304 and the second step 306.

An operation example of FIGS. 2 and 3 according to the present invention will now be described with reference to the waveform diagrams of FIGS. 4 and 5 and the timing diagram of FIG.

First, the video signal generated from the television signal source 3 of FIG. 2 is applied to the synchronous separator 18 of the GCR signal generator 6 configured as shown in FIG. 3 to separate the synchronous signal. At this time, the separated synchronization signal is a composite synchronization signal, and the vertical synchronization pulse and the horizontal synchronization pulse appear as shown in FIG. 6 and are applied to the clock generator 20 and the gating pulse generator 22. The clock generator 20 generates a clock signal of a predetermined frequency synchronized with the input synchronization signal and applies it to the gating pulse generator 22.

Then, the gating pulse generator 22 generates the first and second gating pulses and the field identification signal as shown in FIG. 6 by the synchronization signal and the clock signal, and supplies them to the multiplexer 30. In this case, the first and second gating pulses are pulses that are generated in one horizontal scanning period at a desired position in the vertical blanking interval to overlap the GCR signal, and FIG. 6 shows the GCR signal in the second horizontal scanning period in the vertical blanking interval. Here is an example of nesting. Also, as shown in FIG. 6, the time T1 at which the first gating pulse is generated and the time T2 at which the second gating pulse is generated are the same as the times T1 and T2 shown in FIGS. . The field identification signal is a signal indicating which field is the odd field or the even field. The logic state is reversed. As such, generating the field identification signal from the composite synchronization signal is a technique generally known in the art.

The multiplexer 30 selects signals stored in the first, second and third PROMs 24, 26 and 28 according to the first and second gating pulses and the field identification signals generated as described above, and outputs them as GCR signals. do. At this time, as described above, regardless of the odd or even field, the same GCR signal as shown in FIG. 4 is outputted or the GCR signal of FIG. 5A and GCR signal of FIG. 5B are alternately outputted for each field. If the fourth GCR signal is output, the field identification signal is not used. At this time, the multiplexer 30 outputs a signal 400 including the horizontal synchronization pulse 300 and the burst signal 302 stored in the first PROM 24 during the time Tl at which the first gating pulse is input. During the time T2 at which the two gating pulses are input, a signal 402 including the first step 304 stored in the second PROM 26, the signal 308 of the predetermined level, and the second step 306 is output. . On the other hand, when outputting the GCR signal shown in FIGS. 5A and 5B, the signal is stored in the first PROM 24 and output the signal 400 in the same manner during the time Tl at which the first gating pulse is input. During the time T2 at which the pulse is input, the signal 402 stored in the second PROM 26 or the signal 404 stored in the third PROM 28 are alternately output according to the field identification signal. That is, when the storage signal 402 of the second PROM 26 is output in one field, the storage signal 404 of the third PROM 28 is output in the next field.

As described above, the GCR signal generated by the GCR signal generator 6 is applied as the superimposition signal 5 and superimposed on the television signal for transmission generated by the television signal source 3 before the transmission circuit 7 is transmitted. It is transmitted via the transmission antenna 4, and is received by the television receiver 10 via the reception antenna 8 on the receiving side. At this time, the television signal is not only received at the receiving side by the direct path from the transmitting side to the receiving side as described above, but also by the multipath other than the direct path. The ghosts generated as a result also appear in the GCR signal. Therefore, the receiving side detects and cancels the ghost signal using the GCR signal superimposed on the received television signal.

To this end, the GCR signal separator 12 first separates and applies a GCR signal superimposed on the television signal received by the television receiver 10 to the GCR signal processing circuit 16. The GCR signal processing circuit 16 then processes the separated GCR signal to generate a ghost erase control signal for erasing the ghost signal. At this time, the GCR signal processing circuit 16 detects the ghost information by subtracting the GCR signals in one field and the next field in which the same chroma phase is obtained. If ghost occurs, the ghost signal of the first step appears at a position delayed from the first step of the GCR signal, and if ghost does not occur, the ghost signal of the first step does not appear from the first step of the GCR signal within the maximum ghost section. do. The ghost information detected in this way, that is, ghost presence and ghost position information, is applied to the ghost erase circuit 14 as a ghost erase control signal. The ghost cancellation circuit 14 then cancels the ghost signal by the ghost cancellation control signal from the received television signal. At this time, the first step 1 of the GCR signal is used to deghost the GCR signal, and the second step of the de-ghosted GCR signal is used to perform waveform equalization on the GCR signal and the video signal. That is, when the ghost occurs, the ghost is erased using the first step of the 2T type, and when the distortion of the high frequency component occurs, the second step of the (sin x) / x type including the high frequency is used. After the distortion of the high frequency component is detected, the waveform is equalized to correct the distortion of the high frequency component.

Therefore, by using the GCR signal according to the present invention as described above, it is possible to effectively eliminate the ghost generated in the television signal.

If it is desired to increase the de-ghosting range to more than 30 μs, the feature of "pairing and appearing constant" is adopted so that the GCR signal is jigged over two consecutive vertical blanking intervals. The first of these two vertical blanking interval scanning lines is occupied by a signal that is invariant in time. In this case, the first step 304 of the 2T shape proceeds in the direction of the arrow. Since the algebraically subtracted GCR signal does not include the chroma burst subtracted with the invariant signal and the synchronization signal at the time of the first vertical blanking interval scan line, it averages the 0 IRE signal over the even field to improve the signal-to-noise ratio. Is relatively simple. Thus, the logarithmically added signal contains only 2T steps that change from 0 IRE to 70 IRE and (sin x) / x steps that change from 70 IRE to 0 IRE. If there are signals such as horizontal synch, bursts, and their ghosts, the above ones are subtracted algebraically.

Various criteria regarding the selection of the GCR signal are satisfied by the GCR signal according to the present invention. Therefore, processing a GCR signal for efficient, accurate and economical calculation of deghosting variables and efficient identification of ghost positions under field preconditions, with a minimum vertical retrace scan line required for the transmission of the GCR signal. It is possible.

Thus, a 2T step with a 250µs rise time can be fully specified within about 750ns, which is 11 years of the sampling clock with a frequency of 4fc. fc represents a color subcarrier frequency. Conversely, (sinx) / x steps require a minimum of 2 μs of time. The shorter time-span required for ripple-free as well as 2T step designation provides an efficient means by calculating ghost positions and calculating suitable deghosting filter parameters.

The calculated filter variable depends heavily on the accuracy with which the lobe or ringing part of the (sin x) / x function can be lost. However, as previously mentioned, the signal transmission path can attenuate the video high frequencies that the ringing portion of (sin x) / x actually loses. Thus, there may be no ups and downs of the source (sin x) / x pillars and the received (sin x) / x pillars may be substantially different from the transmitted pulse even in the absence of ghosts. In that condition, the filter parameters calculated using the undulation and ghosted pulses are not optimal.

According to the present invention, a ghosted 2T step, i.e. a received 2T step, is used to calculate the deghosting infinite impulse response (IIR) filter variable. The ghosted GCR signal is processed through this filter to include the GCR signal and provide a deghosted video signal. This signal now contains the deghosted (sin x) / x step and is used to calculate the waveform equalization filter parameters. The filter variable calculated in this way is more accurate than the filter variable calculated using undulating and ghosted (sin x) / x pulses.

The deghosted (sin x) / x step can be analyzed to estimate the effect of near ghost. Next, a decision is made whether to perform waveform equalization, which depends on the positional characteristics of the near-ghost, including position, amplitude, and phase. Typically the required equalization is in the peaking form and uses a finite impulse response (FIR) filter structure. Equalization is executed as soon as the required amount is adequate. It is not considered advisable to perform waveform equalization in a large amount of high frequency attenuation that requires a lot of correction.

The invention has been described by way of examples. Various variations and modifications will be apparent to those of ordinary skill in the art. For example, while generally used examples relate to NTSC systems, the invention is readily applicable to other systems and specifications, including PAL systems and others. The present invention can be applied to transmission by radio wave or cable transmission. Moreover, various time intervals have been used in the examples given. These time intervals are intended to illustrate the fundamental principles of the present invention, and various changes may occur without changing the basic operation. Such changes and modifications are limited only by the following claims and equivalents of the claims, which are within the purpose and scope of the present invention.

Claims (28)

A ghost cancellation reference signal transmission / reception apparatus for erasing ghosts in a television system, comprising: a ghost erasing reference signal generating means for generating a ghost erasing reference signal having a first step of a 2T type leading edge, and for transmitting the ghost erasing reference signal; Superimposing means for superimposing the television signal on the vertical blanking interval, transmission means for transmitting the television with the ghost erase reference signal superimposed, reception means for receiving the transmitted television signal, and the ghost from the received television signal. Ghost erasing reference signal separating means for separating an erasing reference signal, ghost erasing reference signal processing means for processing the separated ghost erasing reference signal to generate a ghost erasing control signal for erasing a ghost signal, and the received television signal By the ghost cancellation control signal Ghost cancellation reference signal transmitting and receiving device characterized in that consists of a ghost cancellation means for canceling the bit signal. 2. The ghost cancellation reference signal multiplier receiving apparatus according to claim 1, wherein the ghost cancellation reference signal is a signal having a second step of a sin x / x form. 3. The apparatus of claim 2, wherein the ghost erase reference signal is a signal having a relatively constant horizontal area between the first step and the second step. 4. The method of claim 3, wherein the first step is a 2T type step that simply changes from 0 IRE to 70 IRE, and the second step is a step of (sin x) / x type that changes from 70 IRE to 0 IRE. And a first erasing reference signal is a signal having a rise time and a fall time of about 250 ns between 10% and 90%, respectively. 5. The apparatus of claim 4, wherein the first step is a signal starting at about 3 mu s after the start of the horizontal synchronizing pulse. 5. The apparatus of claim 4, wherein the first depth is a signal starting at about 33 mu s after the start of a horizontal synchronization pulse. 5. The ghost erasing reference signal transmitting / receiving apparatus according to claim 4, wherein the television signal is suppressed from a chroma scan on a horizontal scan line including the ghost erasing reference signal. 5. The method of claim 4, wherein the first and second steps occur only in the odd field of the television signal, the first step starts at about 30 s after the start of a horizontal sync pulse, and the ghost erase reference signal is of the same chroma phase. And a signal having a flat portion of 0 IRE in place of the first and second steps in the next even field obtained. 9. The apparatus according to claim 8, wherein said ghost erasing reference signal processing means subtracts between said ghost erasing reference signals of said next even field in which the same chroma phase as said ghost erasing reference signal of said odd field is obtained. And a ghost cancellation reference signal transmitting and receiving device, characterized in that generated. 5. The method of claim 4, wherein the first and second steps occur only at the even feed of the television signal, the first step begins at about 30 s after the start of the horizontal sync pulse, and the ghost cancellation reference signal is of the same chroma phase. And a signal having a flat portion of 0 lRE in place of the first and second steps. 11. The apparatus according to claim 10, wherein said ghost erasing reference signal processing means subtracts between said ghost erasing reference signals of said next odd field in which the same chroma phase as said ghost erasing reference signal of said odd field is obtained. And a ghost cancellation reference signal transmitting and receiving device, characterized in that generated. A ghost erase reference signal generator for generating a ghost erase reference signal in a television system, comprising: clock generating means for generating a clock signal in synchronization with a synchronous signal of a video signal, and generating a gating pulse by the synchronous signal and the clock signal; Means for generating a gating pulse, memory means for storing information defining the ghost erase reference signal, and multiplexer means for outputting the information stored in the memory means according to the gating pulse. And a ghost cancellation reference signal generator. 13. The ghost erasing reference signal generator according to claim 12, further comprising a synchronous separation means for separating the synchronous signal from a television signal. 14. The ghost erasing reference signal generating apparatus according to claim 13, wherein said gating pulse generating means generates a field identification signal for identifying a field from said synchronization signal and applies it to said multiplexer means. 15. The apparatus of claim 14, wherein said memory means comprises a plurality of PROMs. 6. The first step of claim 5, wherein the first PROM of the plurality of PROMs stores a horizontal sync filter and a chroma burst signal, and the second PROM is a GCR signal component that changes from 0 IRE to 70 IRE and at 70 IRE. A ghost erase reference signal generator, characterized in that it stores a second step of the form (sin x) / x changed to 0IRE and a signal of a predetermined level between the first step and the second step. A ghost erase method in a television system, comprising: a ghost erase reference signal generation process for generating a ghost erase reference signal having a first step of a 2T edge and a vertical blanking of the television signal for transmitting the generated erase reference signal; An overlapping process of overlapping the interval, a transmitting process of transmitting the television signal superimposed with the ghost erasing reference signal, a receiving process of receiving the transmitted television signal, and the ghost erasing reference signal from the received television signal. A process of separating a ghost erasing reference signal, a ghost erasing reference signal processing for processing a ghost erasing reference signal to generate a ghost erasing control signal for erasing a ghost signal, and the ghost erasing control signal in the received television signal; Ghost clearing process eliminates ghosts Ghost cancellation method which comprises. A ghost cancellation reference signal receiving apparatus in a television system, comprising: receiving means for receiving a television signal in which a ghost cancellation reference signal having a first step of a 2T type leading edge and a first step of a sin x / x type is superimposed And a ghost cancellation reference signal separation means for separating the ghost cancellation reference signal from the received television signal, and a ghost cancellation reference signal for generating a ghost cancellation control signal for processing the separated left ghost cancellation reference signal to erase the ghost signal. And a ghost cancellation means for canceling a ghost signal from the received television signal by the ghost cancellation control signal. 19. The apparatus of claim 18, wherein the ghost cancellation reference signal is a signal having a relatively constant horizontal area between the first step and the second step. 20. The method of claim 19, wherein the first step is a 2T type step that simply changes from 0 IRE to 70 IRE, and the second step is a (sin x) / x step that changes from 70 IRE to 0 IRE. A ghost cancellation reference signal receiver according to claim 1, wherein the first and second steps are signals having a rise time and a fall time of about 250 ns between 10% and 90%, respectively. 21. The apparatus of claim 20, wherein said first step is a signal starting at about 30 [mu] s after the start of a horizontal sync fence. 21. The apparatus of claim 20, wherein said first step is a signal starting at about 33 [mu] s after the start of a horizontal synchronous pulse. 21. The apparatus of claim 20, wherein the received television signal is a signal whose chroma burst is suppressed in a horizontal scan line including the ghost cancellation reference signal. 21. The chroma phase according to claim 20, wherein the first and second steps occur only in the odd field of the television signal, and the first step starts at about 30 s after the start of a horizontal sync pulse, so that the ghost erase reference signal has the same chroma phase. And a signal having a flat portion of 0 IRE in place of the first and second steps in the next even field obtained. The ghost cancellation control signal according to claim 24, wherein the ghost cancellation reference signal processing means subtracts the ghost cancellation control signal by subtracting between the ghost cancellation reference signals of the next even field in which the same chroma phase as the ghost cancellation reference signal of the odd field is obtained. And a ghost cancellation reference signal receiver characterized in that it is generated. 21. The apparatus of claim 20, wherein the first and second steps occur only in the even field of the television signal, the first step starts at about 30 s after the start of a horizontal sync pulse, and the ghost erase reference signal is the same chroma phase. And a ghost cancellation reference signal receiving apparatus characterized by being a signal having a flat portion of 0 IRE in place of the first and second steps in the following odd field. 27. The ghost cancellation control signal according to claim 26, wherein said ghost cancellation reference signal processing means subtracts between said ghost cancellation reference signals of said next odd field in which the same chroma phase as said ghost cancellation reference signal of said even field is obtained. And a ghost cancellation reference signal receiver characterized in that it is generated. 18. The method of claim 17, wherein the ghost erase process comprises: deghosting the ghost erase reference signal using a first step of the ghost erase reference signal, and using a second step of the deghosted ghost erase reference signal. And phasing out the ghost cancellation reference signal and the video signal.

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