KR20060097385A - Channel equalizer of multi media digital broadcasting receiver - Google Patents

Abstract

The present invention relates to a channel equalizer including carrier recovery and gain control. In particular, the present invention further comprises a carrier / gain loop in the channel equalizer of the VSB / QAM integrated receiver, and estimates the residual carrier phase error and the gain error in the carrier / gain loop and compensates them at the output of the linear equalizer. In addition, the error value generated for adapting the tap coefficient of the linear equalizer is multiplied by the inverse of the estimated carrier phase error and the gain error and output to the linear equalizer. Therefore, the VSB / QAM integrated receiver of the present invention can share a channel equalizer including a carrier / gain loop, thereby simplifying a system and reducing hardware cost.

Channel Equalization, Media, Derotation, Rotation

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.

7 is a block diagram illustrating a channel equalization apparatus according to another embodiment of the present invention.

Explanation of symbols for main parts of the drawings

111: linear equalizer 112: noise canceller

113: determination unit 114: error generating unit

311 de-rotation multiplier 312 carrier / gain loop

313: inverse 314: re-rotation multiplier

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 during channel equalization in a VSB / QAM integrated receiver.

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 receiver passes through a multi-path transmission channel, causing intersymbol interference, resulting in a severely distorted state. 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. Accordingly, the noise removing unit 112 estimates the colored noise and removes the colored noise estimated by the equalizer 111 output signal x (n), thereby removing the colored noise amplified in 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's 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 equalization apparatus for estimating residual carrier phase error and residual gain error in a VSB / QAM integrated receiver to compensate from a channel equalized signal.

Another object of the present invention is to provide a channel equalization apparatus for estimating a residual carrier phase error and a residual gain error in a VSB / QAM integrated receiver using multiple antennas to compensate from a channel equalized signal.

According to an aspect of the present invention, there is provided a channel equalizer in a VSB / QAM integrated receiver, including: a signal input unit configured to generate an imaginary signal and output an imaginary signal if the received digital broadcast signal is a QAM signal as it is; An equalizer configured to compensate for channel distortion by adapting an error value to a QAM or VSB received signal input through the signal input unit; A first compensator for complexing and outputting a signal for compensating a residual carrier phase error and a residual gain error to an output of the equalizer; A noise removing unit for predicting and removing noise amplified from the output of the first compensation unit; A decision unit outputting a decision signal closest to the signal output from the noise canceller; A carrier / gain loop configured to receive the output of the noise canceller and the determination signal of the determiner, estimate a residual carrier phase error and a residual gain error, and output a signal to compensate for the residual carrier phase error and the residual gain error; And an error generating unit obtaining an error signal by a difference between an output of the first compensation unit and a determination signal of the determination unit. And a second compensator for multiplying the inverse of the signal output from the carrier / gain loop by the error signal obtained by the error generator and outputting the result to the equalizer.

The carrier / gain loop may include: a reference signal selector configured to generate an imaginary signal from the decision signal when the VSB decision signal is output from the decision unit, and to output the imaginary signal from the decision signal of the QAM method; A reception signal selection unit for delaying a predetermined time when the equalization signal of the VSB method is output from the first compensation unit and outputting the equalized signal when the equalization signal of the QAM method is output; An error output unit for dividing the received signal by a reference signal to obtain an error signal, and outputting a phase value of the error signal as a phase error and an amplitude of the error signal as a gain error; And generating a sinusoidal wave by loop filtering the phase error of the error output unit, generating a gain compensation signal by loop filtering the gain error, and then multiplying the sinusoidal wave and the gain compensation signal to compensate for the residual carrier phase error and the gain error. Comprising a compensation signal output unit for outputting a signal.

The reference signal selector is a Hilbert transformer for Hilbert transforming and outputting the inputted decision signal, a first delayer for delaying the inputted decision signal by the processing time of the Hilbert transformer, and outputting the first delayed signal; 1 is characterized by comprising a selector for selecting a complex signal output from the retarder and the Hilbert transformer, and selects and outputs a determination signal to be input if the QAM signal.

The reception signal selector delays and outputs an equalized signal of a real component input by the processing time of the Hilbert transformer, and outputs the delayed imaginary signal output from the first compensation unit by the processing time of the Hilbert converter. And a selector configured to select a complex signal output from the third and fourth delayers if the equalized signal to be input is a VSB signal and to select and output the equalized signal input to the QAM signal. do.

After receiving the phase error detected in the carrier / gain loop and loop filtering, generating a sine wave corresponding to the result, and a long carrier loop for complex multiplying the received signal to the equalizer and output to the equalizer .

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 this case, the prediction decision feedback equalizer modulates information by using both real and quadrature components, such as quadrature amplitude modulation (QAM), and VSB (Vestigial Side-Band) modulation. Like the method, it can be used for all methods of transmitting information using only real components.

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 passes the real component through a Hilbert Transform filter 212 to create an imaginary component. Typically, the Hilbert transform filter is implemented as a FIR filter and delays the real component in delayer 211 by the time delay that occurs. The complex signal thus produced is input to the linear equalizer of the channel equalizer according to the present invention.

FIG. 3 is a block diagram illustrating an embodiment of a channel equalization device of a VSB / QAM integrated receiver according to the present invention. The linear equalizer 111, the noise canceller 112, and the determiner 113 of FIG. And a de-rotation multiplier 311, a carrier phase / gain loop 312, an inverse 313, and a re-rotation to the error generator 114. Re-rotation multiplier 314 is added to the structure.

The de-rotation multiplier 311 is provided between the linear equalizer 111 and the noise canceller 112, and the output of the de-rotation multiplier 311 is an error generator 114 and a carrier / gain loop ( 312). The carrier / gain loop 312 receives the output of the noise canceling unit 112 and the output of the determining unit 113, and the output of the carrier / gain loop 312 receives the de-rotation multiplier 311 and the inverse unit ( 313). The re-rotation multiplier 314 receives the output of the inverse unit 313 and the output of the error generator 114, and the output of the re-rotation multiplier 314 is provided to the linear equalizer 111.

),gain*sin(

)을 복소곱하여 잡음 제거부(112)와 에러 생성부(114)로 출력한다.That is, the signal x (n) whose channel distortion is compensated by the linear equalizer 111 is output to the de-rotation multiplier 311. The de-rotation multiplier 311 outputs output x (n) of the linear equalizer 111 and output gain * cos of the carrier / gain loop 312.

), gain * sin (

) Is complexed and output to the noise canceller 112 and the error generator 114.

The noise canceller 112 estimates colored noise from the output of the de-rotation multiplier 311 to remove colored noise included in the output of the de-rotation multiplier 311, and then determines the decision unit 113 and the carrier / Output to gain loop 312.

), gain*sin(

)를 추정한다. 즉 상기 반송파/이득 루프(312)는 상기 잡음 제거부(112)의 출력 y(n)과 결정부(113) 의 출력 d(n)을 입력받아 잔류 반송파 위상 에러와 잔류 이득 에러 gain*cos(

), gain*sin(

)를 추정하여 디-로테이션 곱셈기(311)와 역수부(313)로 출력한다. The carrier / gain loop 312 receives an output y (n) of the noise canceling unit 112 and a decision value d (n) of the determining unit 113 determining the carrier phase in a decision-directed manner. Error and Gain Error Signals gain * cos (

), gain * sin (

Estimate). That is, the carrier / gain loop 312 receives the output y (n) of the noise canceller 112 and the output d (n) of the determiner 113, and the residual carrier phase error and the residual gain error gain * cos (

), gain * sin (

) Is estimated and output to the de-rotation multiplier 311 and the inverse unit 313.

), gain*sin(

)의 역수를 계산하여 리-로테이션 곱셈기(314)로 출력한다. 상기 리-로테이션 곱셈기(314)에서는 상기 역수부(313)의 출력 cos(

)/gain, -sin(

)/gain과 에러 생성부(114)의 출력 e(n)을 복소곱하여 선형 등화기(111)로 출력한다. On the other hand, the inverse unit 313 outputs a gain * cos (output signal of the carrier / gain loop 312.

), gain * sin (

The inverse of the) is calculated and output to the re-rotation multiplier 314. In the re-rotation multiplier 314, the output cos (

) / gain, -sin (

) / gain and the output e (n) of the error generator 114 are complex-multiplied and output to the linear equalizer 111.

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 signal, since 8-level discrete signals exist only in the real component, all signals used in the noise canceller 112 and the determiner 113 are real signals. However, since the imaginary component as well as the real component are needed to estimate and compensate for the phase error, in the case of VSB, the carrier / gain loop 312 receives an imaginary component of the derotation multiplier 311.

), sin(

)과 이득 루프(420)의 출력 gain을 복소곱하여 반송 파 위상 에러 및 이득 에러를 보상하는 신호 gain*cos(

), gain*sin(

)를 출력하는 복소 곱셈기(430)로 구성된다. 상기 반송파 루프(410)는 위상 에러 검출기(411), 위상 루프 필터(412), NCO(Numerically Controlled Oscillator)(413)로 구성된다. 상기 이득 루프(420)는 이득 에러 검출기(421), 및 이득 루프 필터(422)로 구성된다. 4 shows a detailed block diagram of the carrier / gain loop 312, which is largely a carrier loop 410, a gain loop 420, and an output cos (of the carrier loop 410).

), sin (

) And the signal gain * cos (compensated for the carrier phase error and the gain error by multiplying the output gain of the gain loop 420).

), gain * sin (

It is composed of a complex multiplier 430 outputting. The carrier loop 410 includes a phase error detector 411, a phase loop filter 412, and a NCO (Numerically Controlled Oscillator) 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.

를 NCO(413)로 출력한다. 상기 NCO(413)는 필터링된 위상 에러

에 해당하는 정현파 cos(

), sin(

)를 생성하여 복소 곱셈기(430)로 출력한다. 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 112 and the determined value d (n) of the determiner 113. The error is calculated and output to the phase loop filter 412. The phase loop filter 412 proportionally integrates the phase error, and as a result

Is output to the NCO 413. The NCO 413 is filtered phase error

Sinusoidal cos corresponding to

), sin (

) Is output 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 112 and the determined value d (n) of the determiner 113, calculates a gain error, and calculates the 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.

), sin(

)과 이득 루프(420)의 이득 루프 필터(422)의 출력 gain을 복소곱하여 반송파 위상 에러 및 이득 에러를 보상하는 신호 gain*cos(

), gain*sin(

)를 디-로테이션 곱셈기(311)과 역수부(313)로 출력한다. The complex multiplier 430 outputs the output cos of the NCO 413 of the carrier loop 410.

), sin (

) And the signal gain * cos (compensating the carrier phase error and the gain error by multiplying the output gain of the gain loop filter 422 of the gain loop 420).

), gain * sin (

) Is output to the de-rotation multiplier 311 and the inverse unit 313.

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 the case of the VSB signal, an imaginary component of the derotation multiplier 311 is received 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 the phase error and the gain error is similar. Therefore, the same process is shared in one block.

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

는 잡음 제거부(112)의 출력 신호의 진폭 및 위상이고

는 결정부(113)의 출력 신호의 진폭 및 위상을 나타낸다. And

Is the amplitude and phase of the output signal of the noise canceller 112

Denotes the amplitude and phase of the output signal of the determiner 113.

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 Hilbert transform unit 512 performs Hilbert transform on the real signal d (n) determined by the determiner 113 to generate an imaginary component reference signal. At this time, the real signal of the decision unit 113, the output signal of the noise canceller 112, and the imaginary signal of the derotation multiplier 311 to compensate for the time delay caused by the Hilbert transform are delayers 511, 514, and 515, respectively. Is delayed by the processing time of the Hilbert transform. That is, in the case of the VSB signal, since only the real component exists in the output signal of the noise canceller 112, the third delay unit 515 receives and delays the imaginary component of the derotation multiplier 311.

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 113 according to a 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 113 according to a 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 113 based on the mode signal and outputs the complex signal to the error generator 517. Selects a complex signal output from the noise canceller 112 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.

6 illustrates a VSB / QAM integrated 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 VSB / QAM integrated receiver of FIG. 3. The difference from the case of the VSB / QAM integrated receiver of FIG. 3 is that the carrier phase error is detected from the output of the noise canceller 112 to compensate for the carrier frequency offset when the QAM signal is received. It includes a long carrier loop that compensates for. To this end, a long carrier phase is provided with a complex multiplier 611 in front of the linear equalizer 111 and a loop filter 612 and an NCO 612 in the complex multiplier 611 and the carrier / gain loop 312. Error compensator 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 linearly equalizes it. Output to the machine 111.

), sin(

)를 생성하여 복소 곱셈기(611)로 출력한다. The phase error obtained by the carrier / gain loop 312 is input to the loop filter 612. The loop filter 612 filters and outputs the phase error to the NCO 613, and the NCO 613 is a sinusoidal cos (corresponding to the filtered phase error).

), sin (

) Is output to the complex 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 doing it. Therefore, it is more suitable when the transmission channel receives QAM, where the transmission channel is a static channel than when the transmission channel is a dynamic channel.

Meanwhile, FIG. 7 is a block diagram illustrating a channel equalizer in a broadcast receiver in a VSB / QAM integrated receiver using multiple antennas according to the present invention, in which the channel equalizer uses a predictive decision feedback equalizer.

As shown in FIG. 7, the NAM linear digital broadcast signals received through the N antennas are subjected to demodulation processes such as automatic gain control (AGC), carrier recovery, and symbol clock recovery. It is input to equalizers 711-71N. That is, the linear equalizer is provided as many as the number of antennas.

The equalizer 710 includes N linear equalizers 711 to 71N provided by the number N of antennas, and an adder for adding and outputting the results of the N linear equalizers.

Since the configuration other than the equalizer 710 is the same structure as the channel equalizer of the VSB / QAM scheme of FIG. 3 described above, the same names and the same reference numerals are provided for convenience of description and detailed description thereof will be omitted.

At this time, each of the linear equalizers 711 to 71N in the equalizer 710 receives the same error value e (n) to adapt the tap coefficient. The outputs of the linear equalizers 711 to 71N are summed in the adder and output to the de-rotation multiplier 311.

),gain*sin(

)과 복소곱하여 잡음 제거부(112)와 에러 생성부(114)로 출력한다.The de-rotation multiplier 311 receives a composite signal of linear equalizers using multiple antennas and outputs gain * cos (of a carrier / gain loop 312).

), gain * sin (

) Is complexed and output to the noise canceller 112 and the error generator 114.

Until now, the present invention has described a process of performing channel equalization by sharing a frequency domain channel equalizer including a carrier / gain loop in a VSB / QAM integrated receiver, but using a separate channel equalizer in a VSB receiver or a QAM receiver, respectively. It is possible to perform channel equalization using the channel equalization apparatus of the present invention as it is without using.

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 sharing the frequency domain channel equalizer including the carrier / gain loop in the VSB / QAM integrated receiver, the system can be simplified and the hardware cost can be reduced.

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 with the residual carrier phase error compensated, the decision 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 residual gain error makes a decision at the decision maker with the compensated signal, the decision error is reduced, thereby improving the performance of channel equalization.

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 (6)

A signal input unit for generating and outputting an imaginary signal if the received digital broadcast signal is a QAM signal as it is; An equalizer configured to compensate for channel distortion by adapting an error value to a QAM or VSB received signal input through the signal input unit; A first compensator for complexing and outputting a signal for compensating a residual carrier phase error and a residual gain error to an output of the equalizer; A noise removing unit for predicting and removing noise amplified at the output of the first compensation unit; A determination unit outputting a determination signal closest to the signal output from the noise canceling unit; A carrier / gain loop configured to receive the output of the noise canceller and the decision signal of the determiner, estimate a residual carrier phase error and a residual gain error, and output a signal to compensate for the residual carrier phase error and a residual gain error; An error generation unit obtaining an error signal by a difference between an output of the first compensation unit and a determination signal of the determination unit; And And a second compensator for multiplying the inverse of the signal output from the carrier / gain loop by the error signal obtained by the error generator and outputting the result of the equalization to the equalizer. The method of claim 1, wherein the carrier / gain loop is A carrier loop which receives the output of the noise canceller 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 noise canceller and the decision signal of the determiner to estimate a gain error and loop filter to output a gain compensation signal; And Channel equalization in a multi-media digital broadcasting receiver comprising a complex multiplier for complexly multiplying a sinusoidal wave output from the carrier loop and a gain compensation signal output from a gain loop to compensate for a residual carrier phase error and a gain error. Device. 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 noise removing unit and outputting the equalized signal when the equalization signal of the QAM method is output; An error output unit for dividing the received signal by a reference signal to obtain an error signal, and outputting a phase value of the error signal as a phase error and an amplitude of the error signal as a gain error; And A sinusoidal waveform is generated by loop filtering the phase error of the error output unit, and a gain compensation signal is generated by loop filtering the gain error, and then a signal that compensates the residual carrier phase error and the gain error by complex multiplying the sinusoidal wave and the gain compensation signal. Channel equalizer in the multi-media digital broadcast receiver, characterized in that consisting of a compensation signal output unit for outputting. The method of claim 3, wherein the reference signal selector A Hilbert converter for Hilbert transforming and outputting an input determination signal; A first delayer for delaying and outputting an input determination signal by the processing time of the Hilbert transformer; In the multi-media digital broadcasting receiver, if the input equalization signal is a VSB signal, the first delay unit and the complex signal output from the Hilbert transformer are selected, and if the QAM signal is selected, the selection unit outputs the selected decision signal. Channel equalizer. The method of claim 4, wherein the received signal selector A third delayer for delaying and outputting an equalized signal of an input real component by a processing time of the Hilbert transformer; A fourth delayer configured to delay and output an imaginary signal output from the first compensation unit by a processing time of the Hilbert transformer; In the multi-media digital broadcasting receiver, if the input equalization signal is a VSB signal, the complex signal output from the third and fourth delayers is selected, and if the QAM signal is input, the selector is configured to select and output the input equalization signal. Channel equalizer. The method of claim 1, After receiving the phase error detected in the carrier / gain loop and loop filtering, generating a sine wave corresponding to the result, and a long carrier loop for complex multiplying the received signal to the sine wave output to the equalizer Channel equalizer in a multimedia digital broadcast receiver.

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