JPH099211A - Waveform equalizer - Google Patents

Abstract

(57) [Summary] [Structure] The reference signal is detected from a video signal having a reference signal (VITS) for performing MUSE waveform equalization processing, and the reference signal is compared with a standard reference waveform. In a waveform equalizer that generates a coefficient of a transversal filter that cancels transmission distortion according to a comparison result, as a synchronous addition processing device for removing noise of the reference signal, the reference signal is an integral multiple of a reference rate. Sampled at the frequency of and all the read data was used for synchronous addition processing. For example, the synchronous addition process, which was the process using the conventional 16.2 MHz rate data, is increased to the 32.4 MHz rate. [Effect] The time required for the synchronous addition processing is halved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to band-compressed MUSE (Multiple Sub-N) for transmitting high-definition signals.
yquist Sampling Encoding) signal to receive and demodulate M
The present invention relates to a waveform equalizer for a USE decoder.

[0002]

2. Description of the Related Art As a high-definition transmission system, MUSE
The method was developed by NHK (Japan Broadcasting Corporation). M
The USE method is a sample value transmission, which is transmitted as an analog sample value sampled at 16.2 MHz. If the characteristics of the entire transmission system including the transmission system to the reception system satisfy Nyquist's distortion-free transmission condition, data can be reproduced without distortion by correctly re-sampling on the reception side. Actually, the MUSE signal undergoes various signal distortions due to the transmission system. Therefore, a device for correcting such transmission distortion and obtaining a signal without distortion is a waveform equalizer.

As a waveform equalizer for MUSE signals,
For example, as disclosed in Japanese Patent Laid-Open No. 64-82778, a Vertical Interval Test inserted as a reference signal for use in waveform equalization in the first and second lines in the vertical blanking period of the MUSE signal. Signal (hereinafter V
It is abbreviated as ITS or VIT signal. ) Is used to detect the transmission distortion, and the tap coefficient of the waveform equalization filter is controlled according to the detected output.

One of the conventional waveform equalizers for MUSE signals
A configuration example is shown in FIG. Input MUSE signal is A / D
It is converted into a digital signal by the converter 1. The A / D-converted MUSE signal passes through the delay circuit 2 and is input to the adder 4 and the transversal filter 3.

The delay circuit 2 is a transversal filter 3
The MUSE signal is delayed in accordance with the delay time of the signal in. At the output of the adder 4, VITS waveform data is detected from the MUSE signal by the VITS detector 8.

The detected VITS waveform data is subjected to synchronous addition processing by the synchronous addition processing unit 9 to reduce noise. In general, various noises are mixed in the MUSE signal in addition to the transmission distortion, and if these noises are erroneously detected as the transmission distortions, the distortions will be added. In order to solve this problem, VIT from MUSE signal
It is possible to reduce noise by capturing the S period only once, instead of capturing it once, and performing the synchronous addition processing of them. In the coefficient generation unit 5, the VITS waveform whose noise has been reduced by the synchronous addition processing unit 9 is converted into an ideal VITS waveform.
Compared to the waveform 7, so that it approaches the ideal VITS waveform,
That is, the tap coefficient of the transversal filter 3 is generated so that an output that cancels the transmission distortion can be obtained from the transversal filter 3. After that, the output of the delay circuit 2 and the transversal filter 3 are added by an adder 4 to remove transmission distortion.

Next, the operation of the synchronous addition processing unit for removing the noise of the VITS waveform will be described with reference to FIGS. 3, 4, and 5. FIG. 5 shows the first line (hereinafter referred to as line # 1) and the second line (hereinafter referred to as line # 2) of the MUSE signal, and the line # 1 has a negative polarity. VITS (hereinafter referred to as VITS # 1)
However, line # 2 has positive VITS (hereinafter, VITS).
It is written as # 2. ) Is superimposed. Further, the VITS waveform is superposed by shifting the phase by one sample data at 32.4 MHz by frame replacement. That is, FIG.
As shown in, Css (C subsample phase control signal)
In the frame when = 0, as shown in (a) and (c), and in the frame when Css = 1,
Since they are superimposed in the sampling phase relationship as shown in (b) and (d), if the data of two frames at Css = 0 and Css = 1 are combined, sampling data at a rate of 32.4 MHz can be obtained.

In the synchronous adder 14 of FIG. 3, Css =
The VITS # 1 16.2 MHz rate data (FIG. 4A) at 0 o'clock is taken N / 2 times, and a synchronous addition process (addition averaging process) is performed. In the synchronous adder 15, 16.2 MHz rate data of VITS # 1 when Css = 1 (see FIG. 4).
(B)) is taken in N / 2 times and a synchronous addition process is performed. Then, the insertion processing unit 16 performs VITS after the synchronous addition.
By shifting the # 1 (Css = 1) waveform by one sample data at 32.4 MHz and inserting it into the VITS # 1 (Css = 0) waveform, the VITS at the 32.4 MHz rate can be obtained.
The # 1 waveform is obtained.

The output of the insertion processing unit 16 is VITS #.
In order to perform an arithmetic mean with 2, the polarity is inverted by the polarity reversing unit 11 and converted into the same positive polarity as VITS # 2.

On the other hand, in the synchronous adder 17 of FIG. 3, C
VITS # 2 16.2 MHz rate data when ss = 0 (FIG. 4 (c)) is taken in N / 2 times and synchronous addition processing is performed. In the synchronous adding unit 18, VITS when Css = 1
The 16.2 MHz rate data of # 2 (Fig. 4 (d)) is transferred to N
/ Twice fetch synchronous addition processing is performed. Then, the insertion processing unit 19 performs VITS # 2 (Css) after the synchronous addition.
= 1) The waveform is shifted by 1 sample data at 32.4 MHz and inserted into the VITS # 2 (Css = 0) waveform to obtain the VITS # 2 waveform at the 32.4 MHz rate. The averaging processing unit 10 averages the output of the polarity reversing unit 11 and the output of the insertion processing unit 19. The output of the synchronous addition processing unit 9 thus obtained is VIT
It is the synchronous addition data for N times of the S 32.4 MHz rate data. Assuming that the time required for N times of synchronous addition processing is T seconds, for example, when the number of times of synchronous addition is N = 128, the number of data at one sample point of VITS in the above processing is one per frame. Since it is a ratio, the required time is T = 4.27 (= 12
8/30) seconds.

[0011]

The time required for the waveform equalization process is dominated by the synchronous addition process. In other words, the user sees a distorted image after turning on the power. Most of the time is the time of the synchronous addition process for reducing the noise of the VITS waveform.

The present invention provides a waveform equalizer which shortens the time required for waveform equalization by shortening the synchronous addition processing time for reducing the noise of the VITS waveform.

[0013]

In order to solve the above-mentioned problems, the present invention uses sampling data at a rate of 32.4 MHz of the VITS waveform in each frame during synchronous addition of the VITS waveform, and further, Css The data of the frame of = 0 is shifted by one sample at 32.4 MHz with respect to the data of the frame of Css = 1, and the phases are matched to perform the synchronous addition processing.

[0014]

According to the present invention, since the VIT signal is sampled at a frequency that is an integral multiple of the reference rate, for example, when the VIT signal is sampled at twice the reference rate, the data amount used for the synchronous addition of the VITS waveform is 2 When the number of times of synchronous addition is the same, the time required for the synchronous addition processing is half that of the conventional case. Therefore, the time required for the waveform equalization processing is significantly reduced.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS.

The configuration of the waveform equalizer shown in FIG. 1 is the same as that of the conventional one shown in FIG. 3 except for the synchronous addition processing section 9, and therefore the description of its configuration and operation will be omitted. Here, in the synchronous addition processing unit 9, 10 is an averaging processing unit, 11 is a polarity inverting unit, 1
Reference numeral 2 is a VITS # 1 (32.4 MHz rate data) synchronous adder, and 13 is a VITS # 2 (32.4 MHz rate data) synchronous adder.

The sampling frequencies of the A / D converter 1 are 16.2 MHz and 32.4 M in the past.
Although it is considered that the sampling frequency is 2 Hz, in the present invention, since sampling data of a rate of 32.4 MHz is used from the beginning, the sampling frequency is 32.4 MH.
Limited to z.

FIG. 2 shows data obtained by sampling VITS # 1 and VITS # 2 at 32.4 MHz when Css = 0 and Css = 1. Since the MUSE signal is originally a band-compressed 16.2 MHz sample value, points other than the transmitted 16.2 MHz rate sample points cannot be used for the demodulation process of the MUSE signal. However, in the VITS period, since it is a continuous signal that is not band-compressed, there is no problem in using all the data obtained by sampling at 32.4 MHz.

In the VITS # 1 synchronous addition of FIG. 1, C
VTS # 1 32.4 MHz rate data at ss = 0 (FIG. 2 (a)) N / 4 times and Css = 1 at VIT
S # 1 32.4 MHz rate data (FIG. 2B) is loaded N / 4 times. Here, the data when Css = 1 is 3
When the phases are matched by shifting by one sampling at 2.4 MHz, N / 2 [(N / 4) * 2] VITS # 1 waveforms having a rate of 32.4 MHz are obtained. Therefore N
/ 2 times of synchronous addition processing is performed. The output of VITS # 1 synchronous addition is added and averaged with VITS # 2.
The polarity inversion unit 11 inverts the polarity and converts it to the same positive polarity as VITS # 2.

On the other hand, in the synchronous adder 13 shown in FIG.
VITS # 2 32.4 MHz rate data when ss = 0 (FIG. 2 (c)) N / 4 times and Css = 1 VIT
S # 2 32.4 MHz rate data (FIG. 2 (d)) is loaded N / 4 times. Here, the data when Css = 1 is 3
When the phases are matched by shifting by 1 sampling at 2.4 MHz, N / 2 [(N / 4) * 2] VITS # 2 waveforms having a rate of 32.4 MHz are obtained. Therefore, N / 2 times of synchronous addition processing is performed. The averaging processing unit 10 averages the output of the polarity inverting unit 11 and the output of the synchronous adding unit 13. The output of the synchronous addition processing unit 9 thus obtained is N times of synchronous addition data of VITS 32.4 MHz rate data.

As can be seen from the above, the time required for the N times of synchronous addition processing is T / 2 seconds in the present invention, where T seconds is the conventional example. For example, when the number N of synchronous additions is 128, the VIT in the processing of the present invention is
Since the number of data of one sample point of S is 2 per frame, the required time is T = 2.
It is 13 (= 128/30/2) seconds.

Further, in the processing of the present invention, assuming that the time given to the synchronous addition processing is T seconds, the synchronous addition processing can be performed 2N times. For example, for synchronous addition processing, T =
If a time of 4.27 seconds is given, 2N = 256 times of synchronous addition processing becomes possible, and the effect of noise reduction is increased.

[0023]

According to the present invention, the amount of data used for the synchronous addition of VITS waveforms is twice as large as that of the conventional one. Therefore, if the number of synchronous additions is the same, the time required for the synchronous addition processing is half that of the conventional one. . Therefore, the time required for the waveform equalization processing is significantly reduced. Further, when the time of the synchronous addition processing is the same, the synchronous addition processing twice as many times as the conventional one can be executed, so that the effect of noise reduction is increased and more accurate waveform equalization can be executed.

[Brief description of drawings]

FIG. 1 is a block diagram showing a basic configuration in an embodiment of the present invention.

FIG. 2 is a waveform diagram showing sampling of the VITS waveform.

FIG. 3 is a block diagram showing a configuration of a conventional waveform equalizer.

FIG. 4 is a signal waveform diagram of a MUSE signal during a VITS period.

FIG. 5 is a signal waveform diagram of line # 1 and line # 2 of the MUSE signal.

[Explanation of symbols]

1 A / D converter 2 Delay circuit 3 Transversal filter 4 Adder 5 Coefficient generation part 6 Sampling clock 7 Standard VITS waveform 8 VITS detection part 9 Synchronous addition processing part 10 Averaging processing part 11 Polarity inverting part 12 VITS # 1 ( 32.4 MHz rate data) synchronous addition unit 13 VITS # 2 (32.4 MHz rate data) synchronous addition unit 14 VITS # 1 (Css = 0, 16.2 MHz rate data) synchronous addition unit 15 VITS # 1 (Css = 1, Css = 1, 16.2 MHz rate data) Synchronous addition unit 16 VITS # 1, 32.4 MHz rate data insertion processing unit 17 VITS # 2 (Css = 0, 16.2 MHz rate data) synchronous addition unit 18 VITS # 2 (Css = 1, 16) .2 MHz rate data) Synchronous adder 19 VITS # 2, 32.4M Hz rate data entry processing unit

Claims (3)

[Claims] 1. A reference signal is detected from a video signal having a reference signal for waveform equalization processing, the reference signal is compared with a standard reference waveform, and transmission distortion is canceled according to the comparison result. In a waveform equalizer that generates the coefficients of such a transversal filter, the synchronous addition processing device for removing noise of the reference signal samples the reference signal at a frequency that is an integer multiple of the reference rate, and reads all the read data. A waveform equalizer, which performs synchronous addition processing on. 2. The waveform equalizer according to claim 1, wherein
The waveform equalizer, wherein the video signal is of a sub-sampled sample value transmission system. 3. The waveform equalizer according to claim 1, wherein
A waveform equalizer, wherein the sampling frequency of data used for synchronous addition processing is the reference rate of 32.4 MHz.