CN101098418A - Equalizer structure and method for error reverse rotation in digital television receiver - Google Patents

Abstract

The invention discloses a balancer structure and method, for using error counter rotation to accurately recover carrier wave, in digit television ground single carrier wave broadcast transmission system, which uses the sum value and error signal of balancer to check phase and filter to obtain a phase error of input signal, and reversely rotate the error signal of the balancer and the sum value of a feedback filter, to correct the phase error, and uses the corrected error signal of balancer to fresh the extract factor of the feedback filter, therefore, the balance is not sensitive to frequency bias of carrier wave, to work at ideal synchronous condition to improve system property.

Description

Be used for equaliser structure and method that digital television receiver carries out error reverse rotation

Technical field

The present invention relates to digital signal transmission field, particularly utilize error reverse rotation carrier wave to be carried out the equaliser structure and the method for meticulous recovery in the digital TV ground single carrier broadcast transmission system.

Background technology

At present, digital terrestrial television transmission system is in Rapid development stage, and is committed to commercial applications.The U.S., Europe, Japan and other countries have all been formulated the digital TV ground transmission standard of oneself in succession.

The Digital Television Terrestrial Broadcasting technology mainly can be divided into two big classes: a class is based on single-carrier technology, and it is mainly represented is ATSC (the Advanced Television Systems Committee) system of the U.S.; An other class is based on multi-transceiver technology, and it is mainly represented is DVB-T (the Digital Vedio Broadcasting-Terrestrial) system in Europe and ISDB-T (the Integrated Services Digital Broadcasting-Terrestrial) system of Japan.

The carrier recovering method that single-carrier system is general comprises and slightly catching and thin the tracking.At the receiving terminal of Digital Television Terrestrial Broadcasting, it is the function that receiver must be finished that carrier wave recovers, otherwise just can't adjudicate normally and decode.Single-carrier system generally uses pilot tone to utilize phase-locked loop to finish slightly catching of carrier wave.In case after carrier frequency was able to synchronously, system just need carry out phase locking and tracking, eliminates phase deviation and shake.General way is the output signal of equalizer to be carried out phase error extract, and through loop filtering, again equalizer output signal is carried out phasing, and wherein section's Stas (costas) ring is the most commonly used.

Fig. 1 has shown the equaliser structure block diagram that uses in the conventional art.Feedforward filter 1 receive through regularly synchronously and the thick base band data after synchronous of carrier wave import as it, and will output to signal superimposer 3 through signal S1 (n) after the filtering.Input to level decision device 4 after signal superimposer 3 superposes S1 (n) and signal S2 (n) (seeing below) and adjudicate, and obtain judgement output D (n).Signal S2 (n) carries out the filtering acquisition by the output D (n) of 2 pairs of level decision devices 4 of feedback filter.The output S (n) of 5 pairs of signal superimposers 3 of error signal maker and the output D (n) of level decision device 4 carry out Error Calculation and obtain error signal output Error1 (n).Forward taps coefficient update device 6 and feedback tap coefficient update device 7 upgrade according to the tap coefficient that this error signal output Error1 (n) controls feedforward filter 6 and feedback filter 2 respectively.

Feedforward filter 1 is finished the filter function to input signal, eliminates preceding footpath and footpath, part back in the multipath signal; Feedback filter 2 carries out filtering to the input signal from decision device output, is used for eliminating back to multipath in the multipath signal; Signal superimposer 3 superposes the output signal of feedforward filter 1 and the output signal of feedback filter 2; Level decision device 4 is finished the decision function to incoming signal level, is used to produce the input of feedback filter and the generation of error signal; Error signal maker 5 carries out Error Calculation to the output signal of signal superimposer and the output signal of level decision device; Forward taps coefficient update device 6 is by being weighted the tap coefficient that upgrades feedforward filter to the error originated from input signal; Feedback tap coefficient update device 7 is by being weighted the tap coefficient that upgrades feedback filter to the error originated from input signal.

But, in conventional equalizer structure shown in Figure 1, because traditional loop need be used through the signal after the judgement and extract phase error, having under the serious channel distortion condition, need equalizer to recover channel substantially, simultaneously, whether whether the operate as normal of equalizer recover closely related with carrier wave again.Like this, balanced and carrier wave recovery can interact, thereby causes the deterioration of systematic function.

In addition, equalizer used in the conventional digital TV ground transmission system also has the carrier track ability, but can have influence on follow-up control to channel, and under high order modulation constellation point crypto set more, the easier influence that is subjected to residual carrier deviation.

Summary of the invention

The objective of the invention is to provides equaliser structure and method a kind of novelty, the meticulous tracking of carrier wave reliably for digital television ground broadcast transmission system.This equaliser structure and method can be carried out carrier synchronization subtly, make equalizer of the present invention can be operated in the desirable synchronous environment, promptly insensitive to the carrier synchronization error, thereby both reliably recovered carrier information, make equalizer be operated in the ideal synchronisation state simultaneously, systematic function is greatly improved.Purpose of the present invention by to equalizer add and the error signal of value and equalizer is carried out phase demodulation and filtering, obtain the phase of input signals error, then to the error signal of equalizer and feedforward filter add and value is carried out derotation revising this phase error, and realize with the tap coefficient that revised equalizer error signal upgrades feedforward filter.

A first aspect of the present invention provides in a kind of digital TV ground single carrier broadcast transmission system utilizes error reverse rotation to the equaliser structure that carrier wave carries out meticulous recovery, comprising: feedforward filter; Feedback filter, input is connected to the level decision device; The signal superimposer, input is connected to described feedforward filter and described feedback filter, and output is connected to described level decision device; Be connected the level decision device between described feedback filter and the described signal superimposer; The error signal maker receives the output signal of the output signal of described signal superimposer and level decision device and generates first error signal; Feedback tap coefficient update device upgrades the tap coefficient of described feedback filter according to described first error signal; Described equaliser structure also comprises: the phase error corrections unit, described phase error corrections unit to described signal superimposer add and value and described first error signal are carried out phase demodulation and filtering, obtain the phase of input signals error, then described first error signal is carried out derotation and obtain second error signal, and before described signal superimposer superposes the sum output signal of feedforward filter, this sum output signal is carried out derotation to revise this phase error; And forward taps coefficient update device, be weighted the tap coefficient that upgrades described feedforward filter by described second error signal to input.

A second aspect of the present invention provides in a kind of digital TV ground single carrier broadcast transmission system utilizes error reverse rotation to the equalizer method that carrier wave carries out meticulous recovery, comprising: input signal is carried out filtering; Output signal after judgement is carried out filtering; To superpose through filtered described input signal and output signal, obtain superposed signal; Finish the decision function of described superposed signal level, produce described output signal; Generate first error signal according to described superposed signal and described output signal; Upgrade tap coefficient when described output signal carried out filtering according to described first error signal; Described method also comprises: the phase error corrections step: described superposed signal and described first error signal are carried out phase demodulation and filtering, obtain the phase of input signals error, then described first error signal is carried out derotation to obtain second error signal, and will before superposeing step, filtered described input signal and output signal carry out derotation to revise this phase error through filtered input signal to described above-mentioned; And forward taps coefficient update step, by described second error signal being weighted the tap coefficient that upgrades when described input signal carried out filtering.

The invention has the advantages that: realize simply can making equalizer insensitive, thereby equalizer being operated in the ideal synchronisation environment, improve the entire system performance carrier wave frequency deviation.

Below in conjunction with drawings and Examples the present invention is described further.

Description of drawings

By the detailed description that will carry out below in conjunction with accompanying drawing, will more know features, objects and advantages of the invention, the corresponding part of same reference symbol sign in the accompanying drawing, wherein:

Fig. 1 is traditional equaliser structure block diagram;

Fig. 2 utilizes error reverse rotation carrier wave to be carried out the equaliser structure block diagram of meticulous recovery in the digital terrestrial television transmission system of the present invention;

Fig. 3 carries out meticulous recovery for the present invention's equaliser structure shown in Figure 2 to carrier wave method flow diagram.

Embodiment

Provide following examples in conjunction with content of the present invention, be applied in the digital tv ground broadcasting.

As shown in Figure 2, identical with prior art shown in Figure 1, the equaliser structure of a preferred embodiment of the present invention also comprises: feedforward filter 1, feedback filter 2, signal superimposer 3, level decision device 4, error signal maker 5, forward taps coefficient update device 6, feedback tap coefficient update device 7.But different is that the present invention also comprises one by phase detectors 8, loop filter 9, digital controlled oscillator 10 and two phase error corrections unit 13 that phase place derotator 11,12 constitutes.

The annexation of equaliser structure of the present invention is as follows: feedforward filter 1 receive through regularly synchronously and the thick base band data after synchronously of carrier wave import as it, it is exported and an input of the phase place derotator 11 of phase error corrections unit 13 is connected.In the phase error corrections unit 13, another input of the output of digital controlled oscillator 10 and phase place derotator 11 is connected.An input of the output of phase place derotator 11 and signal accumulator 3 is connected.3 another inputs are connected with the signal superimposer in the output of feedback filter 2.The output of signal superimposer 3 is connected with the input of level decision device 4.The output of level decision device 4 is connected with the input of feedback filter 2.The output of signal superimposer 3 is connected with error signal maker 5 with the output of level decision device 4.The output of error signal maker 5 is connected with the input of feedback tap coefficient update device 7.The tap coefficient of feedback tap coefficient update device 7 Control and Feedback filters 2 upgrades.The output of error signal maker 5 is connected with an input of phase detectors 8 in the phase error corrections unit 13 simultaneously.The output of signal superimposer 3 is connected with another input of phase detectors 8.In the phase error corrections unit 13, the output of phase detectors 8 is connected with the input of loop filter 9; The output of loop filter 9 is connected with the input of digital controlled oscillator 10; The output of digital controlled oscillator 10 is connected with an input of phase place derotator 12; Another input of phase place derotator 12 is connected with the output of error signal maker 5.The tap coefficient of the output control forward taps coefficient update device 6 of phase place derotator 12 upgrades.

Feedforward filter 1 is finished the filter function to input signal, eliminates preceding footpath and footpath, part back in the multipath signal; Feedback filter 2 carries out filtering to the input signal from decision device output, is used for eliminating back to multipath in the multipath signal; Signal superimposer 3 superposes the output signal behind the output signal process phase place derotator 11 of feedforward filter 1 and the output signal of feedback filter; Level decision device 4 is finished the decision function to incoming signal level, is used to produce the input of feedback filter and the generation of error signal; Error signal maker 5 carries out Error Calculation to the output signal of signal superimposer and the output signal of level decision device; Forward taps coefficient update device 6 is by being weighted the tap coefficient that upgrades feedforward filter to the error originated from input signal; Feedback tap coefficient update device 7 is by being weighted the tap coefficient that upgrades feedback filter to the error originated from input signal; The corresponding function class that loses seemingly in function that above-mentioned these parts are finished and the conventional equalizer shown in Figure 1.Difference as the present invention and routine techniques, the 13 pairs of equalizers in phase error corrections unit add and the error signal of value and equalizer is carried out phase demodulation and filtering, obtain the phase of input signals error, then to the error signal of equalizer and feedforward filter add and value is carried out derotation revising this phase error, and upgrade the tap coefficient of feedforward filter with revised equalizer error signal.

Particularly, in phase error corrections unit 13, phase error detector 8 obtains phase error by the output signal of detection signal superimposer 3 and the output signal of error signal maker 5; 9 pairs of phase errors of loop filter are carried out filtering, obtain the control signal of digital controlled oscillator; Digital controlled oscillator 10 produces the derotation signal according to the output signal of loop filter 9; Phase place derotator 11 carries out derotation according to the output signal of digital controlled oscillator 10 to the output signal of feedforward filter 1; Phase place derotator 12 carries out derotation according to the output signal of digital controlled oscillator 10 to the output signal of error signal maker 5, as the error originated from input signal of forward taps coefficient update device 6.

Below will analyze the difference and the advantage of the present invention and conventional equalizer from principle.

Conventional equalizer structure according to shown in Fig. 1 were it not for carrier deviation, has:

If the input signal of equalizer is:

$\stackrel{\→}{R}\left(n\right)=\stackrel{\→}{x}\left(n\right)---\left(1\right)$

The tap coefficient vector of feedforward filter 1 is designated as

, the tap coefficient vector of feedback filter 2 is designated as

, the output sequence of level decision device 4 is designated as

,  represents convolution algorithm, and then feedforward filter 1 is output as

$S1\left(n\right)=\stackrel{\→}{x}\left(n\right)\⊗{\stackrel{\→}{W}}_{\mathrm{FIR}}\left(n\right)---\left(2\right)$

Feedback filter 2 is output as

$S2\left(n\right)=\stackrel{\→}{D}\left(n\right)\⊗{\stackrel{\→}{W}}_{\mathrm{DFE}}\left(n\right)---\left(3\right)$

Signal superimposer 3 is output as

$S\left(n\right)=\stackrel{\→}{x}\left(n\right)\⊗{\stackrel{\→}{W}}_{\mathrm{FIR}}\left(n\right)+\stackrel{\→}{D}\left(n\right)\⊗{\stackrel{\→}{W}}_{\mathrm{DFE}}\left(n\right)---\left(4\right)$

Level decision device 4 produces the error signal of equalizer

Error1＝D(n)-S(n) (5)

The tap coefficient self adaption of equalizer upgrades the normal LMS (Least Mean Square) of employing algorithm, and concrete update method is:

${\stackrel{\→}{W}}_{\mathrm{FIR}}(n+1)={\stackrel{\→}{W}}_{\mathrm{FIR}}\left(n\right)+\mathrm{\μ}*\mathrm{conj}\left(\mathrm{Error}1\right)*\stackrel{\→}{x}\left(n\right)---\left(6\right)$

${\stackrel{\→}{W}}_{\mathrm{DFE}}(n+1)={\stackrel{\→}{W}}_{\mathrm{DFE}}\left(n\right)+\mathrm{\μ}*\mathrm{conj}\left(\mathrm{Error}1\right)*\stackrel{\→}{D}\left(n\right)---\left(7\right)$

Wherein conj () expression is got conjugate operation to plural number, and μ is the step-length that each tap coefficient upgrades in the LMS algorithm.

When residual carrier deviation Δ f existed, equalizer input signal can be expressed as:

$\stackrel{\→}{R}\left(n\right)=\stackrel{\→}{x}\left(n\right)*e^{-j2\mathrm{\π\Δfn}}---\left(8\right)$

Generally speaking, residual carrier deviation Δ f is less, and following formula can be reduced to:

$\stackrel{\→}{R}\left(n\right)=\stackrel{\→}{x}\left(n\right)*e^{-\mathrm{j\φ}}---\left(9\right)$

In this case, the output of the signal superimposer of conventional equalizer becomes:

$S\left(n\right)=e^{-\mathrm{j\φ}}*\stackrel{\→}{x}\left(n\right)\⊗{\stackrel{\→}{W}}_{\mathrm{FIR}}\left(n\right)+\stackrel{\→}{D}\left(n\right)\⊗{\stackrel{\→}{W}}_{\mathrm{DFE}}\left(n\right)---\left(10\right)$

The tap coefficient update method of feedforward filter is:

${\stackrel{\→}{W}}_{\mathrm{FIR}}(n+1)={\stackrel{\→}{W}}_{\mathrm{FIR}}\left(n\right)+\mathrm{\μ}*\mathrm{conj}\left(\mathrm{Error}1\right)*\stackrel{\→}{x}\left(n\right)e^{-\mathrm{j\φ}}---\left(11\right)$

By following formula as seen, when having residual carrier deviation Δ f, include e in the tap coefficient of conventional equalizer ^{-j φ}Component, promptly tap coefficient can rotate, thereby influences equalizer to the anti-multipath interference capability.

And according to as shown in Figure 2 the present invention, when having residual carrier deviation Δ f, can obtain phase deviation φ in the input signal by phase error detector 8, loop filter 9 and digital controlled oscillator 10, respectively the output S1 (n) of feedforward filter and the error signal Error1 of equalizer are revised by phase place derotator 11 and 12 again, that is:

$S3\left(n\right)=(e^{-\mathrm{j\φ}}*\stackrel{\→}{x}\left(n\right))\⊗{\stackrel{\→}{W}}_{\mathrm{FIR}}\left(n\right)*e^{\mathrm{j\φ}}---\left(12\right)$

error2＝error1*e ^-j (13)

Can obtain the equalizer output signal superimposer like this is output as:

$S\left(n\right)=e^{-\mathrm{j\φ}}*\stackrel{\→}{x}\left(n\right)\⊗{\stackrel{\→}{W}}_{\mathrm{FIR}}\left(n\right)*e^{-\mathrm{j\φ}}+\stackrel{\→}{D}\left(n\right)\⊗{\stackrel{\→}{W}}_{\mathrm{DFE}}\left(n\right)---\left(14\right)$

$=\stackrel{\→}{x}\left(n\right)\⊗{\stackrel{\→}{W}}_{\mathrm{FIR}}\left(n\right)+\stackrel{\→}{D}\left(n\right)\⊗{\stackrel{\→}{W}}_{\mathrm{DFE}}\left(n\right)$

Still according to the LMS algorithm, the update method of forward taps coefficient update device 6 is:

${\stackrel{\&RightArrow;}{W}}_{\mathrm{FIR}}(n+1)={\stackrel{\&RightArrow;}{W}}_{\mathrm{FIR}}\left(n\right)+\mathrm{\&mu;}*\mathrm{conj}(\mathrm{<figure-callout\; id="1"\; label="Error"\; filenames="A20061009348800131.png,A20061009348800151.png"\; state="\{\{state\}\}">Error</figure-callout>}1*e^{-\mathrm{j\&phi;}})*\stackrel{\&RightArrow;}{x}\left(n\right)*-e^{-\mathrm{j\&phi;}}---\left(15\right)$

$={\stackrel{\&RightArrow;}{W}}_{\mathrm{FIR}}\left(n\right)+\mathrm{\&mu;}*\mathrm{conj}\left(\mathrm{Error}1\right)*\stackrel{\&RightArrow;}{x}\left(n\right)$

The update method of feedback tap coefficient update device 7 still is:

${\stackrel{\&RightArrow;}{W}}_{\mathrm{DFE}}(n+1)={\stackrel{\&RightArrow;}{W}}_{\mathrm{DFE}}\left(n\right)+\mathrm{\&mu;}*\mathrm{conj}\left(\mathrm{Error}1\right)*\stackrel{\&RightArrow;}{D}\left(n\right)--\left(16\right)$

Comparison expression (14), (15) and formula (4), (6) can be seen when having residual carrier deviation Δ f, and equalizer output of the present invention and tap coefficient can not be subjected to the influence of residual carrier deviation.The present invention compares with conventional equalizer, increase phase error detector 8, loop filter 9 and digital controlled oscillator 10 and obtained phase deviation φ in the input signal, and the output S1 (n) by 11 pairs of feedforward filters of phase place derotator revises and participates in stack, error signal Error1 by 12 pairs of equalizers of phase place derotator revises, be used for upgrading the tap coefficient of feedforward filter 1, thereby make the tap coefficient of equalizer not be subjected to the influence of residual carrier deviation, be operated in the environment of ideal synchronisation, improve systematic function.

Method of work below in conjunction with accompanying drawing equaliser structure shown in Figure 2 more than 3 pairs is described.Fig. 3 shows the meticulous tracking of carrier wave of the present invention.This job step of utilizing error reverse rotation to carry out meticulous carrier track equalizer method is: flow process starts from step 301; In step 302, digital signal R (n) is input in the feedforward filter 1, the register data displacement in the feedforward filter 1, and the equalizer coefficients with correspondence multiplies each other respectively, through adding and obtaining through filtered output signal S1 (n); In step 303, obtain output signal S2 (n) according to decision signal D (n) at feedback filter 2 places; Flow process advances to step 304 subsequently, in this step, and the output signal S after output signal behind signal S1 (n) the process phase place derotator 11 and S2 obtain superposeing through signal superimposer 3; In step 305, output signal S obtains level decision signal D through over level decision device 4, and this level decision signal is used for the input of error signal maker 5 simultaneously as the input of feedback filter 2; In step 306, error signal maker 5 obtains error signal e rror1 according to S and D; In step 307, error signal e rror1 is input to feedback tap coefficient update device 7 on the one hand, be used for upgrading the tap coefficient of feedback filter 2, output signal S with signal superimposer 3 is input to phase detectors 8 on the other hand, obtain phase error information by certain phase demodulation equation (the phase demodulation equation can adopt imag (S) * real (error1)-real (S) * imag (error1) etc.), to understand as those of ordinary skills, the phase demodulation equation here is not unique, as long as being suitable for being used for extracts phase error information from two signals, all applicable to the present invention; In step 308, phase error information obtains derotation signal e by loop filter 9 and digital controlled oscillator 10 ^{J φ}And e ^{-j φ}In step 309, derotation signal e ^{-j φ}Obtain error2 after multiplying each other with error1 again, be used for upgrading the tap coefficient of feedforward filter 1; At last, flow process ends at step 310.

A base unit of digital tv ground broadcasting is called signal frame, and signal frame is made up of frame head and frame two parts.

Concrete frame structure is as follows:

Frame head (595 symbols)

Frame (containing system information) (3780 symbols)

Frame head is filled the PN sequence, and the length of header signal is 595 symbols, is that length is preceding 595 chips of 1023 m sequence.Frame head all adopts the identical QPSK modulation of I, Q, and character rate is 7.56M.Length is that 1023 m sequence can be realized by a Fibonacci molded lines feedback shift register (LFSR), and reaching " 1 " through " 0 " to+1 value is the binary signal of non-return-to-zero to the mapping transformation of-1 value.

Frame comprises preceding 36 system information symbol and back 3744 data symbols, wherein 36 system information symbol adopt the identical QPSK modulation of I, Q, and 3744 data symbols can adopt 64QAM, 32QAM, 16QAM, 4QAM or 4QAM-NR mapping according to system's needs.

Feedforward filter 1 is made up of 500 grades of FIR filters, feedback filter 2 is made up of 320 grades of iir filters, level decision device 4 is adjudicated according to modulation system that current sign the adopted output S to signal superimposer 3, data D after obtaining adjudicating, error signal maker 5 deducts S with D and obtains error signal e rror1, error1 and S are input in the phase detectors 8, and phase detectors 8 are output as imag (S) * real (error1)-real (S) * imag (error1).Loop filter 9 is made up of an active proportional-integral filter, and 10 of digital controlled oscillators are made up of an accumulator and a look-up table, are output as derotation signal e ^{J }Phase place derotator 11 and 12 is respectively with S1 and error1 and e ^{J }Multiply each other.Error1 and error2 are used for upgrading the tap coefficient of feedback filter 2 and feedforward filter 1 respectively, and its method for updating is (8) formula and (9) formula.

The front provides the description to preferred embodiment, so that any technical staff of this area can realize or use the present invention.Those of ordinary skill in the art will know the various modifications that can make these embodiment easily, and defined here general principle can be applied to other embodiment under the situation of not using the invention ability.Therefore, the present invention does not attempt to be confined to shown embodiment here, but the principle and the new feature the most wide in range corresponding to scope that should meet and be disclosed here.

Claims (8)

1. utilize error reverse rotation to the equaliser structure that carrier wave carries out meticulous recovery in a digital TV ground single carrier broadcast transmission system, comprising:

Feedforward filter (1);

Feedback filter (2), input is connected to level decision device (4);

Signal superimposer (3), input is connected to described feedforward filter (1) and described feedback filter (2), and output is connected to described level decision device (4);

Be connected the level decision device (4) between described feedback filter (2) and the described signal superimposer (3);

Error signal maker (5) receives the output signal (D) of the output signal (S) of described signal superimposer (3) and level decision device (4) and generates first error signal (error1);

Feedback tap coefficient update device (7) upgrades the tap coefficient of described feedback filter (2) according to described first error signal (error1);

Described equaliser structure also comprises:

Phase error corrections unit (13), described phase error corrections unit (13) to described signal superimposer (3) add and value and described first error signal (error1) are carried out phase demodulation and filtering, obtain the phase of input signals error, then described first error signal (error1) is carried out derotation and obtain second error signal (error2), and before described signal superimposer (3) superposeed the sum output signal (S1 (n)) of feedforward filter (1), (S1 (n)) carried out derotation to revise this phase error to this sum output signal; And

Forward taps coefficient update device (6) is weighted the tap coefficient that upgrades described feedforward filter (1) by described second error signal (error2) to input.

2. equaliser structure as claimed in claim 1 is characterized in that, described phase error corrections unit (13) also comprises:

Phase error detector (8), described first error signal (error1) of output signal (S) by detecting described signal superimposer (3) and described error signal maker (5) output obtains described phase error;

Loop filter (9) carries out filtering to the described phase error of described phase error detector (8) output, obtains the control signal of digital controlled oscillator (10);

Digital controlled oscillator (10) produces the first derotation signal (e according to the output signal of described loop filter (9) ^{-j φ}) and the second derotation signal (e ^{-j φ});

Phase place derotator (12) is according to the first derotation signal (e of the output of described digital controlled oscillator (10) ^{-j φ}) described first error signal (error1) of described error signal maker (5) output is carried out derotation; And

Phase place derotator (11) is according to the derotation signal (e of described digital controlled oscillator (10) output ^{J φ}) output signal (S1 (n)) of described feedforward filter (1) is carried out derotation.

3. equaliser structure as claimed in claim 1 is characterized in that, described feedforward filter (1) is made up of 500 grades of FIR filters.

4. equaliser structure as claimed in claim 1 is characterized in that, described feedback filter (2) is made up of 320 grades of iir filters.

5. equaliser structure as claimed in claim 2 is characterized in that, described loop filter (9) is made up of an active proportional-integral filter.

6. equaliser structure as claimed in claim 2 is characterized in that, described digital controlled oscillator (10) is made up of an accumulator and a look-up table.

7. utilize error reverse rotation to the equalizer method that carrier wave carries out meticulous recovery in a digital TV ground single carrier broadcast transmission system, it is characterized in that, comprising:

Input signal is carried out filtering;

Output signal after judgement is carried out filtering;

To superpose through filtered described input signal and output signal, obtain superposed signal;

Finish the decision function of described superposed signal level, produce described output signal;

Generate first error signal (error1) according to described superposed signal and described output signal;

Upgrade tap coefficient when described output signal carried out filtering according to described first error signal (error1);

Described method also comprises:

Phase error corrections step: described superposed signal and described first error signal (error1) are carried out phase demodulation and filtering, obtain the phase of input signals error, then described first error signal (error1) is carried out derotation to obtain second error signal (error2), and will before superposeing step, filtered described input signal and output signal carry out derotation to revise this phase error through filtered input signal (S1 (n)) to described above-mentioned; And

Forward taps coefficient update step is by being weighted the tap coefficient that upgrades when described input signal carried out filtering to described second error signal (error2).

8. equalizer method as claimed in claim 7 is characterized in that, described phase error corrections step also comprises:

By detecting described superposed signal (S) and described first error signal (error1) obtains described phase error;

Described phase error is carried out filtering, obtain first control signal;

Produce the first derotation signal (e according to described first control signal ^{-j φ}) and the second derotation signal (e ^{J φ});

According to the described first derotation signal (e ^{-j φ}) described first error signal (error1) is carried out derotation;

According to the described second derotation signal (e ^{J φ}) carry out derotation to described through filtered input signal (S1 (n)).

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