KR100747583B1 - Channel equalizer of multi media digital broadcasting receiver - Google Patents

Abstract

A channel equalization device for a multi-medium digital broadcasting receiver is provided to estimate a residual carrier phase error and a residual gain error and compensate the residual carrier phase error and the residual gain error from a channel-equalized signal. A channel distortion compensating unit(310) multiplies a received signal by an equalization coefficient, and compensates a channel distortion included in the received signal. A coefficient calculator(380) compensates a residual carrier phase error and a residual gain error included in the received signal, estimates an impulse response from the compensated signal, calculates the equalization coefficient, and provides the calculated equalization coefficient to the channel distortion compensating unit(310). An error compensating unit compensates a residual carrier phase error and a residual gain error included in the signal whose channel distortion is compensated. A decision unit(340) compares the signal outputted from the error compensating unit with a plurality of predetermined reference decision values, and outputs the nearest reference decision value with the signal outputted from the error compensating unit as the last signal. A carrier/gain loop(350) receives the output of the error compensating unit and the decision signal of the decision unit(340), estimates the residual carrier phase error and the residual gain error, and outputs the residual carrier phase error and the residual gain error to the error compensating unit and the coefficient calculator(380).

Description

Channel equalizer of multi media digital broadcasting receiver

1 is a block diagram of a conventional prediction decision feedback equalizer

2 is a general block diagram of a phase separator;

3 is a block diagram illustrating a configuration of a channel equalizer according to an embodiment of the present invention.

4 is a detailed block diagram of the carrier / gain loop of FIG.

5 is a detailed block diagram of the phase error detection and gain error detector of FIG.

6 is a block diagram illustrating a configuration of a channel equalizer according to another embodiment of the present invention.

Explanation of symbols for main parts of the drawings

310: channel distortion compensator 313,320,360: complex multiplier

330: noise removing unit 340: determining unit

350: carrier / gain loop 370: channel estimator

380: coefficient calculation unit 410: carrier loop

411 phase error detector 412 phase loop filter

413 NCO 420 gain loop

421: gain error detector 422: gain loop filter

430: complex multiplier 440: multiplexer

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-media digital broadcast receiver, and more particularly, to a channel equalizer for performing carrier recovery and gain control at the time of channel equalization.

Digital TV reception technology, which is developed in response to various media (terrestrial wave, cable), is gradually being developed as an integrated system structure. Efforts have been made to enable the reception of digital broadcast signals regardless of the media with a single broadcast receiver. ought.

Digital TV transmission methods according to the media are largely classified into VSB (Vestigial Side Band) transmission method through the terrestrial wave and Quadrature Amplitude Modulation (QAM) transmission method using a cable.

In such a multi-media digital transmission system, digital information (voice, data, or video) of a transmitting end is mapped to a symbol, and each symbol is converted into an analog signal proportional to size or phase, and transmitted to the receiving end through a transmission channel. The signal arriving at the receiving end passes through the multi-path transmission channel and causes interference with the adjacent signal, which is severely distorted. Therefore, in order to recover the original signal from the distorted received signal, it is necessary to mitigate the distortion caused by the channel. In this case, a channel equalizer is used.

In general, the most popular channel equalizer is a decision feedback equalizer (DFE). Since the DFE has a small noise increase and includes an Infinite Impulse Response (IIR) filter, the DFE can compensate for signal distortion due to a time delay corresponding to the length of the filter, whereas instability due to a bad decision is disadvantageous. Becomes

One embodiment of a predictive decision feedback equalizer (pDFE) structure having only a linear filter is shown in FIG.

Referring to FIG. 1, the linear equalizer 111 compensates for a distorted signal in a channel by performing adaptive equalization using an input signal u (n) and an error signal e (n).

The signal x (n) whose channel distortion is compensated by the linear equalizer 111 is input to the noise canceller 112.

At this time, the output of the linear equalizer 111 is made up of the sum of the original signal to which the equalization is made and the signal of the color noise which is amplified by the white noise during the equalization process. Therefore, the noise removing unit 112 estimates the colored noise and subtracts the colored noise estimated from the actual colored noise, thereby removing the colored noise amplified during the equalization process.

To this end, the noise removing unit 112 is largely composed of a subtractor 112-1 and a noise predictor 112-2.

The subtractor 112-1 removes the predicted colored noise from the linear equalized signal to remove the colored noise amplified in the equalization process. The noise predictor 112-2 estimates colored noise from the determined value of the noise canceled signal and outputs the colored noise to the subtractor 112-1.

The signal from which the noise is removed by the noise remover 112 is output for channel decoding and is also output to the determiner 113.

The determiner 113 outputs a decision value closest to the output of the noise remover 112 to the noise predictor 112-2 and the error generator 114.

The error generator 114 obtains a difference between the output of the linear equalizer 111 and the output of the determiner 113 and outputs the difference to the linear equalizer 111 as an error signal.

In this case, the prediction decision feedback equalizer of FIG. 1 replaces the noise reduction function obtained when the noise predictor 112-2 uses the decision feedback filter, but uses only a linear equalizer to equalize the distortion of an area such as the decision feedback equalizer. Longer filters are required for this. In addition, when a broadcast is received in a downtown or indoor area, strong distortion due to signal interference is generated, and in order to linearize it, the length of the filter needs to be considerably longer. In this case, if the linear equalizer is implemented as a finite impulse response (FIR) filter in the time domain, the hardware complexity is greatly increased.If the least mean square (LMS) method is used as an adaptive algorithm, the equalizer can be stably followed as the filter length increases. The disadvantage is that the rate of channel change is slower.

In addition, the demodulator (not shown) performs frequency and phase recovery of a carrier before performing channel equalization. If a residual carrier phase error that is not sufficiently compensated is input to the channel equalizer, the performance of channel equalization is further deteriorated. Let it go. Similarly, before the channel equalization, the demodulator performs automatic gain control, which maintains the input signal at an appropriate size, but also causes a residual gain error, which degrades the performance of channel equalization.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a channel equalizer for estimating a residual carrier phase error and a residual gain error in a multi-media digital broadcasting receiver to compensate from a channel equalized signal.

According to an embodiment of the present invention, a channel equalization apparatus in a multi-media digital broadcasting receiver includes: a channel distortion compensator for multiplying a received signal by an equalization coefficient to compensate for channel distortion included in the received signal. ; A coefficient calculator for compensating the residual carrier phase error and the residual gain error included in the received signal, estimating a channel impulse response from the compensated signal, calculating an equalization coefficient, and outputting the equalized coefficient to the channel distortion compensator; An error compensator configured to compensate for a residual carrier phase error and a residual gain error included in the channel distortion compensated signal; A decision unit outputting a decision signal closest to the signal output from the error compensation unit; And a carrier / gain loop that receives the output of the error compensator and the decision signal of the determiner, estimates a residual carrier phase error and a residual gain error, and outputs the residual compensator to the error compensator and the coefficient calculator.

The channel distortion compensation unit may compensate for the channel distortion included in the signal received in the frequency domain.

The coefficient calculating unit estimates a channel impulse response by using a conjugate gradient algorithm, and calculates an equalization coefficient that minimizes the mean square error.

A channel equalizer in a multi-media digital broadcasting receiver according to an embodiment of the present invention receives a phase error detected in the carrier / gain loop, performs loop filtering, generates a sine wave corresponding to the result, and receives a received signal in the sine wave. It is characterized in that it further comprises a long carrier loop which is complex-multiplied and output to the channel distortion compensator.

The channel equalizer of the multi media digital broadcasting receiver according to an embodiment of the present invention predicts the amplified noise during equalization from the output of the error compensator and the output of the decision compensator to correct the amplified noise included in the signal output from the error compensator. Characterized in that it further comprises a noise removing unit for removing.

According to another embodiment of the present invention, a channel equalization apparatus in a multimedia broadcasting receiver includes: a long carrier loop for compensating for a long residual carrier phase error included in a received signal; A channel distortion compensator for multiplying the signal output from the long carrier loop by an equalization coefficient to compensate for channel distortion included in a signal received in a frequency domain; A coefficient calculator for compensating the residual carrier phase error and the residual gain error included in the received signal, estimating a channel impulse response from the compensated signal, calculating an equalization coefficient, and outputting the equalized coefficient to the channel distortion compensator; An error compensator configured to compensate for a residual carrier phase error and a residual gain error included in the channel distortion compensated signal; A decision unit outputting a decision signal closest to a signal output from the error compensation unit; And a carrier / gain loop that receives the output of the error compensator and the decision signal of the determiner, estimates a residual carrier phase error and a residual gain error, and outputs the residual compensator to the error compensator and the coefficient calculator.

Other objects, features and advantages of the present invention will become apparent from the following detailed description of embodiments taken in conjunction with the accompanying drawings.

Hereinafter, with reference to the accompanying drawings illustrating the configuration and operation of the embodiment of the present invention, the configuration and operation of the present invention shown in the drawings and described by it will be described as at least one embodiment, By the technical spirit of the present invention described above and its core configuration and operation is not limited.

The same components as in the related art are denoted by the same names and the same reference numerals for convenience of description, and detailed description thereof will be omitted.

The channel equalizer of the present invention proposes a system including a carrier loop and a gain loop in a predictive decision feedback equalizer (pDFE) structure.

In particular, the present invention proposes a system including a carrier loop and a gain loop in a conjugate gradient prediction decision feedback equalizer structure.

At this time, the prediction decision feedback equalizer uses a real component (In-Phase) and a imaginary component (Quadrature-Phase) such as QAM to transmit information, and a real component such as VSB (Vestigial Side-Band) modulation method. It can be used for both methods of transmitting information using only.

Therefore, all the signals of FIG. 1 become complex signals, and since only real components exist in the VSB modulation scheme, the phase separator of FIG. 2 is used to form an imaginary component.

The phase separator of FIG. 2 includes a retarder 211 and a Hilbert transformer 212, and a real component signal is input to a Hilbert transform unit 212 to form an imaginary component. Typically, a Hilbert transducer is implemented with a FIR filter, which inverts the real component signal by 90 ° and converts it into an imaginary component signal. At this time, the delay unit 211 delays and outputs a signal of a real component input for the processing time of the Hilbert transformer 212. The complex signal generated by the phase separator is input to the channel distortion compensator of the channel equalizer according to the present invention.

3 is a block diagram illustrating an embodiment of a channel equalizer in a multi-media digital broadcasting receiver according to the present invention, and includes a channel distortion compensator 310, a complex multiplier 320 and 360, a noise remover 330, and a determiner ( 340, a carrier phase / gain loop 350, a channel estimator 370, and a coefficient calculator 380.

The channel distortion compensator 310 includes an overlapper 311, a fast fourier transform (FFT) unit 312, a complex multiplier 313, an IFFT unit 314, and an extractor 315.

In the present invention configured as described above, the input signal u (n) received through the transmission channel is superimposed at a preset overlap ratio (for example, 50%) in the overlapping portion 311 of the channel distortion compensator 310 so as to overlap the FFT unit. Is output to 312. The input signal u (n) is also output to the complex multiplier 360.

The FFT unit 312 converts the overlapped signal of the time domain output from the overlapping unit 311 into a frequency domain after outputting the FFT to the complex multiplier 313. In this case, the reason for performing FFT while overlapping the input signal is to make the frequency domain equalization process the same as the linear weaving operation because it is the same as the circular weaving operation in the time domain.

The complex multiplier 313 complexly multiplies the equalization coefficient w (n) calculated by the coefficient calculating unit 370 with the superimposed signal U (n) of the frequency domain output from the FFT unit 312 and the FFT unit 312. After compensating for the channel distortion of the frequency-domain superimposed signal output from the PDU, the signal is output to the IFFT unit 314. The IFFT unit 314 IFFTs the overlapping signal X (n) in the frequency domain in which the distortion of the channel is compensated, converts it to the time domain, and outputs the result to the extraction unit 315. The extractor 315 extracts the valid signal x (n) from the superimposed signals transformed into the time domain and outputs the valid signal x (n) to the complex multiplier 320. That is, the extractor 315 extracts only valid data corresponding to the linear convolutional operation from the overlapping data output from the IFFT unit 314 and outputs the valid data to the complex multiplier 320.

The complex multiplier 320 complexes the output x (n) of the extractor 315 and the output gain * cos (φ) and gain * sin (φ) of the carrier phase / gain loop 350 to extract the extractor ( The residual phase error and the residual gain error included in the output signal of 315 are compensated for.

Meanwhile, the complex multiplier 360 complexly multiplies the input signal u (n) and the output gain * cos (φ) and gain * sin (φ) of the carrier phase / gain loop 350 to be included in the input signal u (n). The residual phase error and the residual gain error are compensated for and output to the channel estimator 370.

The channel estimator 370 uses a conjugate-gradient (CG) algorithm to output an impulse response h (n) of the channel from the output d (n) of the complex multiplier 360 and the determiner 340. After estimating the output to the coefficient calculation unit 380.

의 행렬 연산을 해 줌으로써 보다 정확한 채널을 추정할 수 있게 된다. 이때 상기 채널 추정부(370)는

연산을 직접 수행하지 않고 반복 연산에 의해 채널을 추정하는 CG 알고리즘을 적용하여 채널의 임펄스 응답을 추정한다.That is, the channel estimator 370 obtains a cross correlation value p between a received signal input through the complex multiplier 360 and a reference signal input through the determination unit 340, and cross-correlates the cross signal. The autocorrelation matrix R of the value p and the reference signal is obtained. Then, to remove the autocorrelation portion existing in p that is the cross correlation value of the received signal and the reference signal.

By performing the matrix operation of, it is possible to estimate a more accurate channel. At this time, the channel estimator 370

The impulse response of the channel is estimated by applying a CG algorithm that estimates the channel by iterative rather than performing the operation directly.

As described above, the channel estimator 370 can estimate the impulse response of the channel simply by applying the CG algorithm.

The impulse response of the channel estimated by the channel estimator 370 is output to the coefficient calculator 380. The coefficient calculator 380 obtains an equalization coefficient w (n) of a frequency domain that minimizes a mean square error (MMSE) using the estimated impulse response of the channel and outputs the equalization coefficient w (n) to the complex multiplier 313. do.

On the other hand, assuming that frequency equalization is perfectly performed in the channel distortion compensator 310, the signal output from the channel distortion compensator 310 is regarded as a sum of an original signal and colored noise. Can be.

Therefore, the output of the complex multiplier 320 is input to the noise remover 330 and finally output after the colored noise amplified by the channel distortion compensator 310 is removed.

The noise canceller 330 includes a subtractor 331 and a CG noise predictor 332. The CG noise predictor 332 receives the output of the complex multiplier 320 and the output of the determiner 340, and predicts amplified noise during equalization by applying a CG algorithm.

The subtractor 331 whitens the noise included in the equalized signal by subtracting the noise predicted by the CG noise predictor 332 from the equalized signal output from the complex multiplier 320.

The output of the noise canceller 330 is output to the determiner 340 and the carrier phase / gain loop 350.

The determiner 340 outputs a decision value closest to the output of the noise remover 330 to the CG noise predictor 332, the complex multiplier 360, and the carrier / gain loop 350.

The carrier / gain loop 350 receives the output of the noise canceling unit 330 and the output of the determination unit 340 and compensates for the residual carrier phase error and gain error compensation signals gain * cos (decision-directed). φ) and gain * sin (φ) are estimated. The output of the carrier / gain loop 350 is provided to complex multipliers 320 and 360.

At this time, if the received signal is a signal of the QAM method, all the signals of FIG. 3 are complex signals. If the received signal is a VSB type signal, since 8-level valid data exists only in the real component, all signals used in the noise removing unit 330 and the determination unit 340 are real signals. However, since the imaginary component as well as the real component are required to estimate and compensate for the phase error, in the case of VSB, the carrier / gain loop 350 receives and uses an imaginary component output from the complex multiplier 320.

4 is a detailed block diagram showing an embodiment of the carrier / gain loop 350. The carrier loop 410, the gain loop 420, and the carrier loop 410 of FIG. Complex outputting the signal gain * cos (φ) and gain * sin (φ) to compensate for residual carrier phase error and gain error by multiplying the output cos (φ), sin (φ) and the output gain of the gain loop 420 A multiplier 430.

The carrier loop 410 is composed of a phase error detector 411, a phase loop filter 412, and a numerically controlled oscillator (NCO) 413.

The gain loop 420 is composed of a gain error detector 421 and a gain loop filter 422.

In this case, the phase loop filter 412 of the carrier loop 410 and the gain loop filter 422 of the gain loop 420 are typically first-order filters including a proportional part and an integral part. Can be configured.

In the carrier / gain loop configured as described above, the phase error detector 411 of the carrier loop 410 receives the output y (n) of the noise canceller 330 and the determined value d (n) of the determiner 340. The carrier phase error is calculated and output to the phase loop filter 412. The phase loop filter 412 proportionally integrates the residual carrier phase error, and as a result, outputs φ to the NCO 413. The NCO 413 generates a sinusoidal cos (φ) and sin (φ) corresponding to the filtered residual carrier phase error φ and outputs it to the complex multiplier 430.

Similarly, the gain error detector 421 of the gain loop 420 receives the output y (n) of the noise canceller 330 and the determined value d (n) of the determiner 340, and calculates a gain error. Output to the loop filter 422.

The gain loop filter 422 performs proportional integral filtering on the input gain error and outputs the result to the complex multiplier 430. The output of the gain loop filter 422 is used as the final gain control signal gain.

The complex multiplier 430 complexly multiplies the output cos (φ), sin (φ) of the NCO 413 of the carrier loop 410 and the output gain of the gain loop filter 422 of the gain loop 420 by a carrier phase error. And the signals gain * cos (φ) and gain * sin (φ) for compensating the gain error, to the complex multipliers 320 and 360.

Further, a multiplexer 440 is further provided between the gain loop 420 and the complex multiplier 430 for the case where the gain loop 420 is not used. The multiplexer 440 selects an output of the gain loop 420 or a constant 1 according to a gain loop enable signal and outputs the final gain control signal gain to the complex multiplier 430.

In this case, in the case of the QAM signal, y (n) and d (n) input to the carrier loop 410 and the gain loop 420 are complex signals, and in the case of the VSB signal, y (n) and d (n) are real signals. to be. In addition, in the case of the VSB signal, an imaginary component of the complex multiplier 320 is input and used.

FIG. 5 is a detailed block diagram illustrating an embodiment of the phase error detector 411 of the carrier loop 410 and the gain error detector 421 of the gain loop 420. The process of obtaining a carrier phase error and a gain error is shown in FIG. Since they are similar, the same process is shared in one block.

5 illustrates a first delay unit 511, a first Hilbert transformer 512, a first selector 513, a second delay unit 514, a third delay unit 515, and a second selector 516. , An error generator 517, a phase error output unit 518, and a gain error output unit 519.

는 잡음 제거부(330)에서 출력되는 신호의 진폭 및 위상이고

는 결정부(340)에서 출력되는 신호의 진폭 및 위상을 나타낸다. And

Is the amplitude and phase of the signal output from the noise canceller 330

Denotes the amplitude and phase of the signal output from the determiner 340.

In this case, since the QAM signal has information on both real and imaginary components, the reference signal is generated by discriminating complex numbers.

However, in the case of the VSB signal, since there is no information on the imaginary component, the real signal d (n) determined by the determiner 340 is Hilbert transformed by the Hilbert transformer 512 to generate an imaginary component reference signal. At this time, the real signal of the decision unit 340, the output signal of the noise canceller 330, and the imaginary signal of the complex multiplier 320 are compensated for each time delay due to the Hilbert transform. Delayed by the processing time of the conversion. That is, in the case of the VSB signal, since only the real component exists in the output signal of the noise removing unit 330, the third delay unit 515 receives and delays the imaginary component of the complex multiplier 320.

The first selector 513 selects a complex signal output through the delay unit 511 and the Hilbert transformer 512 or a complex signal output from the determiner 340 according to the mode signal and generates an error generator 517. )

The second selector 516 selects a complex signal output through the first and second delayers 514 and 515 or a complex signal output from the determiner 340 according to the mode signal and generates an error generator 517. Will output

The mode signal is used to select an input to be used by the first and second selectors 513 and 516 according to whether the received signal is a VSB signal or a QAM signal. That is, if the received signal is a VSB signal, the first selector 513 selects a complex signal output through the delay unit 511 and the Hilbert transformer 512 based on the mode signal, and outputs the complex signal to the error generator 517. The second selector 516 selects a complex signal output through the third and fourth delayers 514 and 515 and outputs the complex signal to the error generator 517.

If the received signal is a QAM signal, the first selector 513 selects a complex signal output from the determiner 340 based on the mode signal, outputs the complex signal to the error generator 517, and the second selector 516. Selects a complex signal output from the noise canceller 330 and outputs the complex signal to the error generator 517.

). The error generator 517 obtains an error signal by dividing the output signal of the first selector 513 by the output signal of the second selector 516 (

).

) 중 위상 값에 해당하는 부분(

)을 위상 루프 필터(412)로 출력한다. 그리고 이득 에러 출력부(519)는 상기 에러 신호(

) 중 진폭에 해당하는 부분(

)을 위상 루프 필터(412)로 출력한다.At this time, the phase value of the error signal is a phase error, and the amplitude of the error signal is a gain error. Therefore, the phase error output unit 518 is the error signal (

), Which corresponds to the phase value (

) Is output to the phase loop filter 412. And the gain error output unit 519 is the error signal (

Of the amplitude corresponding to the amplitude (

) Is output to the phase loop filter 412.

FIG. 6 illustrates a channel equalizer of a multimedia digital broadcast receiver including a long carrier loop. As can be seen from FIG. 6, the basic structure is the same as that of the carrier / gain loop of the multi-media digital broadcasting receiver of FIG. 3. That is, when the QAM signal is received, the long carrier loop includes a carrier phase error detected from the output of the channel distortion compensator 310 and compensated by the input terminal of the channel distortion compensator 310 to compensate for the carrier frequency offset. It is different from FIG. To this end, the multi-media digital broadcasting receiver of FIG. 6 includes a complex multiplier 611 in front of the channel distortion compensator 310 and a loop filter 612 between the complex multiplier 611 and the carrier / gain loop 350. A long carrier phase error compensator with an NCO 613 is added.

That is, the complex multiplier 611 multiplies the input signal u (n) by the sine wave corresponding to the carrier phase error output from the NCO 613 to compensate for the carrier phase error included in the input signal u (n) and then channel distortion. Output to the compensator 310.

The phase error obtained by the carrier / gain loop 350 is input to the loop filter 612. The loop filter 612 performs proportional integral filtering on the phase error and outputs the result to the NCO 613. The NCO 613 generates a sinusoidal cos (φ) and sin (φ) corresponding to the filtered phase error and complexes it. Output to the multiplier 611.

In this case, the long carrier loop has an advantage of obtaining a more stable error value by using an equalizer output with distortion compensated by ghost, whereas the long delay loop does not track the change of the dynamic channel well. There is a drawback to not. Therefore, it is suitable when the transport channel receives the QAM, which is a static channel, than the case of the VSB which is frequently the dynamic channel. That is, in the case of a QAM modulation receiver, a loop for tracking a carrier at the equalizer input may be configured by using a phase error detector using the equalizer output.

In the frequency domain prediction decision feedback equalizer structure including the carrier / gain loop according to the present invention described above, one hardware may be shared between a QAM modulation receiver and a VSB modulation receiver.

On the other hand, the terms used in the present invention (terminology) are terms defined in consideration of the functions in the present invention may vary according to the intention or practice of those skilled in the art, the definitions are the overall contents of the present invention It should be based on.

The present invention is not limited to the above-described embodiments, and can be modified by those skilled in the art as can be seen from the appended claims, and such modifications are within the scope of the present invention.

As described above, the channel equalizer of the VSB / QAM integrated receiver according to the present invention has the following effects.

First, by using the conjugate gradient algorithm, the equalizer can compensate for the distortion of the channel even in a dynamic channel with a fast channel change.

Second, it is possible to estimate the residual carrier phase error that is not sufficiently removed in the demodulator and compensate for it at the output of the channel equalizer.

Third, since the determination part makes a decision with the signal having the residual carrier phase error compensated for, the determination error is reduced, thereby improving the performance of channel equalization.

Fourth, it is possible to estimate the residual gain error that is not sufficiently eliminated in the demodulator and compensate for it at the output of the channel equalizer.

Fifth, since the determination part makes a decision with the residual gain error compensated for, the decision error is reduced, thereby improving the performance of channel equalization.

Sixth, in the case of QAM reception, the equalizer output is used to obtain an accurate error value, and the error value can be used to compensate the carrier frequency offset at the equalizer input terminal.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the spirit of the present invention.

Therefore, the technical scope of the present invention should not be limited to the contents described in the embodiments, but should be defined by the claims.

Claims (14)

A channel distortion compensator for multiplying a received signal by an equalization coefficient to compensate for channel distortion included in the received signal; A coefficient calculator for compensating the residual carrier phase error and the residual gain error included in the received signal, estimating a channel impulse response from the compensated signal, calculating an equalization coefficient, and outputting the equalized coefficient to the channel distortion compensator; An error compensator configured to compensate for a residual carrier phase error and a residual gain error included in the channel distortion compensated signal; A decision unit comparing the signal output from the error compensation unit with a plurality of preset reference determination values and outputting the reference determination value closest to the signal output from the error compensation unit as a final signal; And And a carrier / gain loop configured to receive an output of the error compensator and a decision signal of the determiner, estimate a residual carrier phase error and a residual gain error, and output the residual compensation to the error compensator and the coefficient calculator. Channel equalizer at the broadcast receiver. The method of claim 1, wherein the channel distortion compensator A channel equalizer in a multi-media digital broadcasting receiver, characterized in that for compensating for channel distortion included in a signal received in a frequency domain. The method of claim 2, wherein the channel distortion compensator A frequency domain converter for converting the received signal into a frequency domain by overlapping the received signal at a preset overlap ratio; A compensator for compensating for channel distortion by multiplying an overlapping signal converted from the frequency domain converter to a frequency domain by an equalization coefficient calculated by the coefficient calculator; And And a time domain converter configured to convert the overlapped signal in the frequency domain compensated for the channel distortion into a time domain, and extract and output a valid signal from the overlapped signal. The method of claim 1, If the received digital broadcast signal is a QAM signal, and if it is a VSB signal, the channel equalization in the multi media digital broadcast receiver further comprises a signal input unit for generating an imaginary signal and outputting the channel distortion compensator and the coefficient calculator. Device. The method of claim 1, wherein the coefficient calculating unit Estimate the channel impulse response using a conjugate gradient algorithm, and calculate an equalization coefficient for minimizing the mean square error. The method of claim 1, wherein the carrier / gain loop is A carrier loop which receives the output of the error compensator and the decision signal of the determiner, estimates a phase error, performs a loop filtering, and generates and outputs a sine wave corresponding to the result; A gain loop that receives the output of the error compensator and the decision signal of the determiner and estimates a gain error and loop filters the gain compensation signal to output a gain compensation signal; And And a complex multiplier for multiplying a sine wave output from the carrier loop and a gain compensation signal output from the gain loop and outputting a signal for compensating for a residual carrier phase error and a gain error. . The method of claim 1, wherein the carrier / gain loop is A reference signal selection unit for generating an imaginary signal from the determination signal when the VSB determination signal is output from the determination unit and outputting the imaginary signal from the determination signal; A reception signal selection unit for delaying a predetermined time when the equalization signal of the VSB method is output from the error compensation unit, and outputting the equalized signal when the equalization signal of the QAM method is output; An error output unit for dividing the reference signal by a received signal to obtain an error signal, and outputting a phase value of the error signal as a carrier phase error and an amplitude of the error signal as a gain error; And Generating a sinusoidal wave by loop filtering the carrier phase error of the error output unit, generating a gain compensation signal by loop filtering the gain error, and compensating the residual carrier phase error and the gain error by complexing the sinusoidal wave and the gain compensation signal. A channel equalizer in a multi-media digital broadcasting receiver, characterized in that the compensation signal output unit for outputting a signal. The method of claim 1, And a long carrier loop for loop filtering the received phase error detected by the carrier / gain loop, generating a sinusoid corresponding to the result, and multiplying the sinusoidal signal by the received signal to the channel distortion compensator. A channel equalizer in a multi-media digital broadcast receiver. The method of claim 1, And a noise removing unit for predicting amplified noise during equalization from the output of the error compensator and the output of the determiner to remove amplified noise included in the signal output from the error compensator. Channel equalizer at. The method of claim 9, wherein the noise canceling unit A noise predictor configured to receive the output of the error compensator and the output of the determiner and predict amplified noise during equalization by applying a conjugate gradient algorithm; And a subtractor configured to whiten the noise by subtracting the noise predicted by the noise predictor from the output of the error compensator. A long carrier loop to compensate for the long residual carrier phase error included in the received signal; A channel distortion compensator for multiplying the signal output from the long carrier loop by an equalization coefficient to compensate for channel distortion included in a signal received in a frequency domain; A coefficient calculator for compensating the residual carrier phase error and the residual gain error included in the received signal, estimating a channel impulse response from the compensated signal, calculating an equalization coefficient, and outputting the equalized coefficient to the channel distortion compensator; An error compensator configured to compensate for a residual carrier phase error and a residual gain error included in the channel distortion compensated signal; A decision unit outputting a decision signal closest to the signal output from the error compensation unit; And And a carrier / gain loop configured to receive an output of the error compensator and a decision signal of the determiner, estimate a residual carrier phase error and a residual gain error, and output the residual compensation to the error compensator and the coefficient calculator. Channel equalizer at the broadcast receiver. 12. The system of claim 11 wherein the long carrier loop is And performing loop filtering on the carrier phase error detected by the carrier / gain loop, and multiplying the received sinusoid and the received signal to the channel distortion compensator for outputting the received signal to the channel distortion compensator. The method of claim 11, wherein the coefficient calculating unit A channel equalizer in a multi-media digital broadcast receiver characterized by estimating a channel impulse response by applying a conjugate gradient algorithm and calculating an equalization coefficient that minimizes the mean square error. The method of claim 11, And a noise canceller configured to receive the output of the error compensator and the output of the determiner, predict amplified noise during equalization by applying a conjugate gradient algorithm, and then remove the amplified noise included in the signal output from the error compensator. Channel equalizer in a digital media broadcast receiver, characterized in that configured.

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