KR940008122B1 - Multi-transmission apparatus of tv signal - Google Patents

Abstract

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Description

TV signal multiple transmission device

1 is a block diagram showing a TV signal multiplexing apparatus at a transmitting side in accordance with an embodiment of the present invention.

2 is a block diagram showing a TV signal multiplexing transmission apparatus at a receiving side according to an embodiment of the present invention.

3 and 4 show waveform examples of the ghost removal reference signal for the main NTSC signal and the multiple signal according to one embodiment of the present invention.

5 and 6 are detailed diagrams of a ghost removal reference signal embedded in a conventional NTSC signal.

FIG. 7 is a block diagram showing a TV signal multiplexing apparatus at a transmitting side using conventional orthogonal amplitude modulation. FIG.

8 is a block diagram showing a TV signal multiplexing apparatus at a receiving side using conventional orthogonal amplitude modulation.

9 is a diagram showing various frequency spectra in a TV signal multiplexing transmission apparatus using conventional quadrature amplitude modulation.

10 is a block diagram showing a conventional two-dimensional waveform equalizer.

FIG. 11 is a diagram showing an example of an NTSC signal penetrating a conventional orthogonal channel and a reference signal for ghost cancellation of multiple signals. FIG.

* Explanation of symbols for main parts of the drawings

1: Multiple Signal Generator 2: NTSC Signal Generator

3 controller 4 multi GCR generator

5, 6: switch 7: GCR generator

8, 19: carrier generator 9, 31, 14, 15: modulator

10: frequency separator 11: frequency converter

12: orthogonal modulator 13, 30: adder

16, 33: Inverse Nyquist filter 17, 34: VSB filter

18, 35: synthesizer 20, 44: ideal phase

21, 41: Nyquist filter 22, 42: Bandpass filter

23, 24, 43, 46: demodulator 25: luminance color difference separator

26: frequency converter 27: quadrature demodulator

36 transmitter 39 quadrature modulator

45: carrier reproducer 47: goost eliminator

48: NTSC Decoder 49: Multiple Goost Eliminator

51: two-dimensional horizontal filter 52: GCR detector

53: coefficient calculator 70: orthogonal demodulator

The present invention relates to an apparatus for transmitting / receiving a specific signal multiplexed with the television signal by inserting an amplitude modulator television signal into which a coarse oscillation reference signal is inserted and a subheading reference signal.

More than 30 years have passed since the current National Television System Committee (NTSC) color television broadcast was launched in 1960. Recently, various new methods including high definition TV systems have been proposed in pursuit of high definition and high performance television systems. At the same time, the content of the program braked to the viewer is also changing from a simple studio program to a program having a higher definition and a higher sense of reality, such as a movie of a cinema size.

Current NTSC broadcasts are standardized to 525 scan players, 2: 1 interlaced scans, luminance signal bandwidth 4.2MHz and aspect ratio 4: 3 (eg, Prichard's "American Color Television Principle-Review"). , IEEE Trans.Consumer Electron., Vol.CE-23, pp. 467-478, November 1977).

Under such a background, various television signal synthesis methods have been proposed for the purpose of enhancing horizontal resolution and expanding aspect ratio while having compatibility with the current broadcasting system. One such method is the "EDTV (Extended Definition TV) method using quadrature modulation of an image carrier with an Nyquist filter" by Yasmoto et al., IEEE Trans. Consumer Electron, vol. CE-33. Pp. 173-180, published in August 1987. This paper describes a signal overlapping method using orthogonal modulation of a video carrier. According to this method, in principle, various signals are transmitted to a conventional NTSC receiver using a newly installed orthogonal channel having local interference.

One of the big problems in terrestrial broadcasting is the multimodal deformation of radio waves. This problem has recently attracted much attention of TV viewers because many high-rise buildings in the urban area reflect the waves. If the orthogonal channel is installed using the above method, crosstalk occurs between the main NTSC channel and the multiplexed signal by the multiplicity of deformation.

In order to eliminate the multiplicity of deformation, "Development of a reference signal for removing ghost for TV broadcasting" Miyazawa et al., IEEE Trans. As described in On Broadcasting, Vol. 35, No. 4, pp. 339-347, December 1989, a ghost removal reference signal can be inserted between one of the vertical retrace lines of the main NTSC signal. do. According to this paper, as shown in Figs. 5 (a), (b) and 6, the 18th and 281th Sinx / x rising bar signals and the penetal signals are determined by the 8-feed sequence method. Insert at the horizontal line. In FIG. 6, the 17th and 18th lines are shown to clarify the use of the 8 feed sequence GCR signal. In order to obtain the GCR signal from the 8-day continuous on the receiving side, it can be calculated according to the following equation.

GCR = 1/4 [(F0-F4) + (F5-F1) + (F2-F6) + (F7-F3)]... … … (One)

Here, F _x (X = 0, 1, 2, ...) is the X-th feed signal.

If the image signal contains a still image on the seventeenth line (although there is normally no image signal on this line), this calculation removes the image signal, the horizontal synchronization signal, and the color subcarrier, so there is almost no multiplicity distortion. A pure GCR signal can be obtained.

Orthogonal modulation of a video carrier is one of the excellent techniques for maintaining luxury with conventional TV broadcasting. However, crosstalk between two channels caused by incomplete channel deformation of the demodulation on the receiving side is caused. This is actually multimodal or ghosted. In order to reduce multiplicity distortion by orthogonal modulation, a method of inserting a ghost cancellation reference (GCR) signal into both an NTSC signal and a multiplex signal has already been proposed. For example, the paper "NTSC-compatible large-screen TV system that can expand and develop" Kageyama et al., IEEE Trans. Consumer Electrins, CE-34, No. 3, published in August 1988. According to this paper, as shown in Fig. 11, the Sinx / x GCR signal is inserted into the horizontal line during the vertical retrace period. In this case, two horizontal lines are necessary for transmitting the GCR signal, one horizontal line is for transmitting the main GCR signal and no signal for multiple channels, and the other horizontal line is for transmitting black burst and multiple GCR signals for the main channel. It is to. The drawback of this method is the consumption of two horizontal lines during each retracement period.

10 is a block diagram showing a two-dimensional waveform synchronizer suitable for assimilating a main NTSC signal and a multiple signal. This moving picture is composed of two unit delay lines, four sets of multipliers and two sets of adders, and equalizes both the main NTSC signal and the multiple signal. Both signals generate tap weights with reference to themselves and the other party to compensate for crosstalk from the ghost and the other party caused by them. All tap coefficients are provided by the post-calculation control (not shown) for the GCR signal.

It is a main object of the present invention to provide a multiplex TV signal transmission apparatus using orthogonal modulation of video carriers for multiplex transmission in a limited bandwidth without interfering with the current receiver.

According to the present invention, in order to save channel capacity without changing the conventional NTSC TV standard including the main GCR signal, multiple GCR signals for multiple signals are inserted on the same horizontal line as the line for inserting the main GCR signal of the conventional standard. It is done.

According to the present invention, multiple signals such as side panel signals of a wide screen image, high frequency components of luminance signals, or digital PCM audio signals can be transmitted using orthogonal modulation of a video carrier. At the same time, a conventional TV receiver can continuously receive a conventional video without interference from multiple signals, and can realize a TV signal transmission apparatus that reduces crosstalk between two signals and transmits multiple signals more efficiently. Even in the event of circuit imperfections such as filters and modulators, crosstalk of the main signal to multiple signals can be reduced to a level that can actually be ignored.

According to the present invention, a TV signal multiplexing apparatus in a transmission axis is an NTSC (or conventional) generating an NTSC (or conventional) signal having a feed sequence main GCR signal inserted in a horizontal line in a vertical blanking period. A composite signal source and a multiple signal source for generating multiple signals with a corresponding embedded sequencing part GCR signal inserted in the horizontal line, such as an NTSC composite signal into which the main GCR signal is inserted.

The NTSC composite signal modulates a main video carrier to form a residual sideband (VSB) signal, and the multiple signal is the same frequency as the main signal and amplitude modulates a carrier wave 90 ° phase shifted from the main signal. It becomes a signal. The modulated multiple signal passes through an inverse Nyquist filter to become a residual sideband signal, and is then superimposed on the modulated main signal and transmitted as a multiple signal.

The TV signal multiplexing apparatus on the receiving side includes a synchronous detector for demodulating the main NTSC signal and the multiple signal, and a multiple ghost eliminator comprising a two-dimensional horizontal filter, a GCR signal detector and a coefficient calculator. In the multiple ghost canceller, the GCR signal detector detects both the GCR signal and the multiple signal embedded in the NTSC signal, thereby obtaining crosstalk from the NTSC signal to the multiple signal and the ghost of the multiple signal. The coefficient calculator calculates all coefficients of the two-dimensional transverse filter to reduce crosstalk and ghosting.

With such a configuration, it is possible to obtain multiple signals at the reception side as well as conventional TV broadcast images without crosstalk therebetween. In particular, an advantage of the present invention which can be emphasized is that both GCR signals are inserted into the same horizontal line during the vertical retrace period, thereby saving channel capacity.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIG. 1A is a block diagram showing a TV signal multiplexing apparatus at the transmitting side as an embodiment of the present invention. In the same figure, the multiple signal generator 1 generates a multiple signal having a frequency band of about 1 MHz and no DC component. The high frequency component of the luminance signal and the high frequency component of the side panel correspond to multiple signals. The NTSC signal generator 2 generates an NTSC composite signal or an NTSC encoded signal. The main GCR generator 7 and the multiple GCR generators 4 and the other two GCR signals are inserted into the NTSC composite signal and the multiple signal via the switchers 5 and 6 controlled by the controller 3, respectively. do. Horizontal lines during the vertical return period are used for this insertion. The method of controlling these switchers is mentioned later. NTSC and multiple signals having these GCR signals are orthogonally modulated in an orthogonal modulator composed of modulators 9 and 31, an idealizer 32, and a carrier generator 8. The carrier wave is generated in the carrier generator 8 and supplied after being phase shifted by 90 ° via two modulators, namely, one directly to the modulator 31 and the other to the phase shifter 32. The modulated NTSC composite signal and the modulated multiple signal are added by the synthesizer 35 after passing through the VSB filter 34 and the inverse Nyquist filter 33. A synthesized RF modulated signal is obtained from the synthesizer and transmitted through a transmitter and an antenna.

FIG. 1 (b) shows a method of controlling the switchers 5, 6 and two GCR generators 4, 7 by the controller 3. In the controller 3, the frame detector 301 searches for the first frame or the second frame and the first or second feed of each frame from the input NTSC composite signal. Referring to the burst signal on the back porch of the NTSC composite signal, it is possible to determine the start of the first feed of the first frame. The 18H detector 302 detects the position of the 18H line and outputs control signals for two switchers to the switch so that the GCR signal is inserted. The control signal generator 303 generates a feed selection signal and selects a ROM (read only memory) inside the GCR generator 7 and the multiple GCR generators 4 to generate an 8 feed or 4 feed sequence GCR signal. do.

2 is a block diagram showing a multiple TV signal receiving apparatus for receiving a signal transmitted from the transmitting apparatus shown in FIG. 1A as an embodiment of the present invention. The receiver receives the synthesized RF modulated signal via an antenna and a tuner to reproduce the original NTSC signal and the original multiple signal. The synthesized RF modulated signal is input to the Nyquist filter 41 and the band pass filter 42. The orthogonal demodulator 70 is composed of a carrier regenerator 45, a demodulator 43, 46, and an ideal group. NTSC composite signals and multiple signals are obtained by demodulator 43 and demodulator 46, respectively. The demodulated NTSC composite signal is introduced into the ghost canceller 47, NTSC decoder 48 if necessary. Goost-free luminance signals and chrominance signals are obtained from NTSC decoders.

On the other hand, the demodulated multiple signal is introduced into the multiple goost canceller 49 to remove crosstalk from its own ghost and NTSC signals. The multiple ghost remover 49 consisting of the two-dimensional horizontal filter 51, the GCR detector 52, and the number calculator 53 extracts the GCR signal from a predetermined horizontal line according to a predetermined equation to be described later, and the two-dimensional horizontal filter. The coefficient 530 for the multiplier of is calculated. This coefficient 530 is introduced into the two-dimensional transverse filter. The details of the two-dimensional transverse filter are shown in FIG. Both the NTSC composite signal and the multiple signal are supplied to the two-dimensional horizontal filter 51 to reduce or eliminate cross talk from the ghost of the multiple signal and the NTSC composite signal to the multiple signal.

An example of an orthogonal modulation method applied to a TV signal multiplexing apparatus is shown in FIG. In this example, the high frequency component of the luminance signal is transmitted using orthogonal modulation of the video carrier. Referring to FIG. 7, the input signal is the luminance signal Y and the color difference signals I and Q, and the output signal is a composite RF modulated signal indicated by "n". The input luminance signal Y is separated into a low frequency component Y _L having a frequency band of less than 4.2 MHz and a high frequency component Y _H having a frequency band of 4.2 MHz to 5.3 MHz in the frequency injector 10. On the other hand, the input color difference signals I and Q are orthogonally modulated in a quadrature modulator 12 using a subcarrier fsc having a frequency of about 3.58 MHz, and the low frequency component Y of the luminance signal in the adder 13. _L ) is added to form an NTSC composite signal indicated by "g". This process involves exactly "NTSC coding". The high frequency component Y _H of the luminance signal is frequency-converted in the frequency changer 11 to be a multiple signal indicated by " h " having a frequency band from DC to 1.0 MHz. The multiple signal h and the NTSC composite signal g are orthogonally modulated in modulators 14 and 15 by video carriers coswt and sinwt. The modulated multiple signal and the modulated NTSC signal pass through the inverse Nyquist filter 16 and the VSB filter 17, respectively, and are added to each other by the synthesizer 18 to form a synthesized RF modulated signal n. The frequency spectra of the luminance signal (Y), multiple signal (h), NTSC signal (g) and composite RF modulated signal (n) are shown in Figures 9 (a), (b), (c) and (d), respectively. It is.

FIG. 8 is a block diagram showing a TV signal multiplex receiver for receiving a signal transmitted from the transmitter shown in FIG. In Fig. 8, the input signal is a composite RF modulated signal indicated by " a ", and the output signal is a luminance signal Y and a color difference signal I, Q. The input RF modulated signal is introduced into both the Nyquist filter 21 and the bandpass filter 22. The frequency spectrums of the outputs of the Nyquist filter 21 and the bandpass filter 22 are shown in Figs. 9 (f) and (g). These output signals are supplied to an orthogonal demodulator composed of demodulators 23 and 24 and orthogonally demodulated by carriers sinwt and coswt. The demodulated multiple signal, denoted "d", is also introduced into the frequency converter 26 to have the frequency spectrum shown in FIG. The demodulated NTSC signal indicated by "e" is output to the luminance chrominance separator 25. The luminance signal " g " is obtained from the output of the buzzer 25, and the color difference signals I and Q are obtained from the orthogonal demodulator 27. The luminance signal " g " is added by the synthesizer 30 together with the high frequency components of the luminance signal frequency-converted from the frequency converter 26 to become the original wideband luminance signal Y.

3 is a first embodiment of the application of the GCR signal in this TV signal multiplexing apparatus. In the figure, the left waveform entitled "In-phase Channel" is a conventional standard used in Japan, and the right waveform represents a GCR signal for multiple signals via an orthogonal channel. In each of the in-phase and quadrature channels, the GCR signal is inserted at the eighteenth horizontal line in the vertical retrace period. The GCR signal in the orthogonal channel consists of 1 and -sinx / x signals having a 4 feed sequence and having a bandwidth of about 1 MHz. This GCR signal has no DC component (suitable for orthogonal channels) and its sequence is-,-, + and + as shown in this figure. A conventional ghost canceller accepts a synthesized RF modulated signal including a quadrature modulated signal having a GCR signal, and accepts a synthesized RF modulated signal including a quadrature modulated signal having a GCR signal according to equation (1). When calculating the GCR signal according to the crosstalk, the crosstalk from the multiple GCR signal to the main GCR signal is eliminated by the feed sequence characteristic of the GCR signal for the multiple signal. This means that the orthogonal modulation with the new GCR signal is compatible with the conventional goost cancellation TV.

When calculating crosstalk from an NTSC signal to multiple signals, simply follow the equation In other words,

Crosstalk = (F0 + F2) or (F5 + F7)... … … … … … … … … … … … … … (2)

By this calculation, the ghost of the multiple signal can be eliminated. In case of calculating the ghost of the multi-signal itself, the following equation can be used. In other words,

Ghost of Multiple Signals = (F3-F1) or (F6-F4)... … … … … … … (3)

By this calculation, crosstalk from an NTSC signal to a multiple signal can be eliminated. Another way of calculating this is as follows. In other words,

Ghost of multiple signal a = (F2-F0) or (F7-F5). … … … … (4)

Alternatively, a part of formulas (3) and (4) or a combination of these formulas may be used.

These calculations can be performed in the GCR detector 52 of FIG.

4 is a second embodiment of the application of the GCR signal in such a TV signal multiplexing apparatus. In the figure, the left waveform titled " in-phase channel " is a conventional standard used in Japan, and the right drawing shows a multi-signal GCR signal via an orthogonal channel. For each in-phase channel and orthogonal channel, the GCR signal is inserted at the 18th horizontal line in the vertical blanking period. The GCR signal in the orthogonal channel has a 4 feed sequence, and consists of a + and − sinx / x signal and a no signal with a bandwidth of about 1 MHz. This GCR signal does not have a DC component (suitable for orthogonal channels) and its sequence becomes no signal,-, no signal, and + as shown in the figure. When a conventional ghost canceller receives a composite RF modulated signal including orthogonal modulation with a GCR signal and calculates a GCR signal according to Equation (1), the crosstalk from the multiple GCR signal to the main GCR signal is applied to the multiple signal. It is eliminated by the feed sequence characteristic of the GCR signal. This means that the orthogonal modulation with the new GCR signal is compatible with the conventional ghost removing TV.

When calculating crosstalk from an NTSC signal to a multiple signal, one can simply see the 18th line of the multiple signal in the periods 0, 2, 5, 8, or a combination of these.

When calculating the ghost of the multi-signal itself, one can see the 18th line of the multi-signal in the feed 3, feed 6, feed 1 or feed 4. This calculation is performed in the GCR detector 52 of FIG.

As described above, since the present invention can demodulate multiple signals transmitted through orthogonal modulation accurately and efficiently even under difficult conditions such as multi-wave propagation, the industrial value of orthogonal modulation of an image carrier is very useful. It is obvious. In addition, by using the present invention, not only the conventional NTSC TV standard but also the conventional ghost elimination standard are compatible, it is possible to transmit multiple signals, and the radio wave resource can be effectively used.

Claims (16)

A first signal modulating means for modulating a main signal with a first video carrier to obtain a residual amplitude band amplitude modulated signal, and a multi-signal with a second video carrier having a 90 ° frequency or phase equal to that of the first video carrier Second signal modulating means for obtaining a carrier suppression amplitude modulation signal, first insertion means for inserting a first ghost removal reference signal on a horizontal line during a vertical retrace period of the main signal, and the horizontal line of the main signal And a second inserting means for inserting a reference signal for removing the second ghost on the horizontal line of the multiple signal. The signal of claim 1, wherein the first goost removing reference signal includes a sinx / x rising bar signal at the feeds 1, 3, 6, and 8, and a pemestal signal at the feeds 2, 4, 5, and 7. TV signal multiplexing apparatus, characterized in that. The apparatus of claim 1, wherein the second ghost removal reference signal comprises a positive signal at feeds 1 and 2 and a negative signal at feeds 3 and 4. The apparatus of claim 1, wherein the second ghost removal reference signal comprises sinx / x at the feeds 3 and 4 and -sinx / x at the feeds 1 and 2. 2. The apparatus for multiplexing TV signals according to claim 1, wherein the second ghost removal reference signal comprises a bipolar signal at the feed 2, a negative signal at the feed 4, and no signal at the feeds 1 and 3. . The TV signal according to claim 1, wherein the second ghost removal reference signal is composed of sinx / x at the feed 4, -sinx / x at the feed 2, and no signal at the feeds 1 and 3. Multiplexing device. First signal demodulation means for demodulating a main signal from a composite RF modulated signal transmitted through orthogonal modulation of an image carrier, second signal demodulation means for demodulating a multiple signal from the composite RF modulated signal, and A first separating means for separating the first ghost removal reference signal inserted into the horizontal line during the vertical retrace period, and a second ghost removal inserted into the same horizontal line as the first ghost removal reference signal insertion line from the multiple signals; Second separation means for separating the reference signal for the signal, crosstalk removing means for removing crosstalk from the synthesized signal to the multiple signal, and ghost removal means for removing the ghost of the multiple signal. TV signal multiplexing apparatus. 8. The first goost removing reference signal includes a sinx / x rising bar signal at the feeds 1, 3, 6 and 8 and a pedestal signal at the feeds 2, 4, 5 and 7. TV signal multiplexing apparatus. 8. The TV signal multiplexing apparatus according to claim 7, wherein the second ghost removal reference signal comprises a positive signal at the feeds 1 and 2 and a negative signal at the feeds 3 and 4. 8. The TV signal multiplexing apparatus according to claim 7, wherein the second ghost removal reference signal comprises sinx / x at the feeds 3 and 4 and -sinx / x at the feeds 1 and 2. 8. The TV signal multiplex signal according to claim 7, wherein the second goust removing reference signal is composed of a bipolar signal at the feed 2, a negative signal at the feed 4, and no signal at the feeds 1 and 3. Device. The TV signal according to claim 7, wherein the second ghost removal reference signal is composed of sinx / x at feed 4, -sinx / x at feed 2, and no signal at feeds 1 and 3. Multiplexing device. 8. The crosstalk removal means detects crosstalk by a sum of feeds 1 and 3, or a sum of feeds 6 and 8, or a combination of these sums, and the goust removal means comprises: A TV signal multiplexing apparatus, characterized by detecting a ghost by a difference between the feeds 5 and 7 or a combination of these differences. 8. The crosstalk removal means according to claim 7, wherein the crosstalk removal means detects crosstalk by calculating a signal inserted into the first, the third, the six, and the eight, or a combination of these, Wherein the ghost is detected by calculation of a signal inserted in, or in a combination of, the two of the two. A first signal source for generating an NTSC composite signal, a second signal source for generating a multiple signal having no DC component, and a waveform consisting of one or more different unit reference signals, the waveform being in the four-feed sequence of the NTSC composite signal. Therefore, the first signal generating means for generating the first goth removal reference signal consisting of the unit reference signals in turn, and the waveform comprises one or more different unit reference signals, A second signal generating means for generating a second ghost removal reference signal comprising a unit reference signal, and a first ghost removal reference on a horizontal line during the vertical retrace period of the NTSC composite signal to obtain an NTSC composite signal having a GCR; A first insertion means for inserting a signal, and a horizontal signal of said multiple signal such as said horizontal line of said NTSC composite signal by obtaining a multiple signal having a GCR; A second insertion means for inserting a reference signal for removing a ghost, first signal modulating means for modulating the NTSC composite signal having a GCR to a first video carrier to obtain a first residual sideband amplitude modulation signal, and a carrier wave Second signal modulating means for modulating the multiple signal having a GCR into a second video carrier having the same frequency as the first video carrier but having a phase different from 90 ° in order to obtain the suppressed both sideband amplitude modulation signals, and a second residual signal An inverse Nyquist filter having a Nyquist characteristic for filtering both sideband amplitude modulated signals suppressed by the carrier to obtain a sideband amplitude modulated signal, and the first and second residual sideband amplitude to obtain a composite RF signal. And a synthesizing means for adding a modulated signal and a transmitting means for transmitting the synthesized RF signal. A TV signal multiplexing apparatus in a TV signal receiving system for receiving a composite RF signal, comprising: first signal demodulation means for demodulating an NTSC composite signal from the composite RF signal transmitted through orthogonal modulation of an image carrier, and the composite RF signal; Second signal demodulation means for demodulating a multiple signal from the signal, first separation means for separating a first ghost removal reference signal inserted in a horizontal line during a vertical blanking period from the NTSC composite signal, and the first signal from the multiple signal. A second separation means for separating a twelfth ghost removal reference signal inserted into a horizontal line, such as a first ghost removal reference signal insertion line, and calculating crosstalk from the first and second ghost control reference signals to calculate the crosstalk; Crosstalk detection means for detecting crosstalk from a signal to the multiplex signal, and calculating a ghost from the second ghost removal reference signal to perform the multiplexing; TV comprising: a ghost detection means for detecting a ghost of an arc, a crosstalk removing means for giving reverse crosstalk by a first horizontal filter, and a ghost removal means for giving reverse ghost by a second horizontal filter. Signal Multiplexer.

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