CN100340109C - Carrier reset device - Google Patents
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- CN100340109C CN100340109C CNB031340695A CN03134069A CN100340109C CN 100340109 C CN100340109 C CN 100340109C CN B031340695 A CNB031340695 A CN B031340695A CN 03134069 A CN03134069 A CN 03134069A CN 100340109 C CN100340109 C CN 100340109C
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Abstract
The present invention provides a carrier recovery device which relates to a device for recovering carriers after receiving data sent in a vestigial side band (VSB) modulation mode. The present invention is characterized in that after VSB signals are modulated into offset quadrature amplitude modulation(OQAM) signals, real number component signals and imaginary number component signals in the modulated OQAM signals are multiplied, or the squared value of the two kinds of signals are calculated first, and then the difference value of the two kinds of signals are calculated, or the difference value of the two kinds of signals are calculated after the absolute value is calculated; then the phase error of carriers is calculated according to the obtained value. Thus, the device of the present invention can correctly recover carriers without pilot frequency signals in a VSB transfer mode. Especially in an urban core, the present invention can accurately finish recovering carriers even though pilot frequency signals weaken or disappear in an inclement channel environment with many reflected waves.
Description
Affiliated field
The present invention will be referred to digital television receiver, will be referred to the carrier centering device of VSB mode digital television receiver especially.
Background technology
At present, the Digital Television of the Korea S and the U.S. (abbreviating DTV as) the VSB residual sideband mode that broadcast standard adopted is stipulated, requires to utilize the existing frequency of distributing to analog television broadcast to send broadcast singal.But, in order to reduce influence as far as possible, compare with anolog TV signals intensity to present analog television broadcast, be the signal that removes to transmit DTV with very weak signal strength signal intensity.Certainly, in the DTV signal, in order to reduce The noise, regulation adopts means such as multiple coded system and channel equalizer, so, although signal strength signal intensity a little less than, in the reception of DTV signal, do not have what problem., if transmit the situation very severe of channel, received signal normally so just.Usually, the DTV load mode, when receiving broadcast signal, its advantage is owing to can remove the noise that takes place on the channel transmitting fully, can see the image without any noise.On the contrary, its shortcoming is if can not recover to transmit signal fully, so simply just to cannot see image.So, require the DTV receiver no matter under the RST of abominable transmission channel, all should be able to receive how.
Fig. 1 is the structured flowchart of common VSB mode digital television receiver.When receiving the radio frequency rf signal of modulating with the VSB mode by antenna 101, then tuner 102 will only be selected after the required specific channel frequency of user, and the VSB signal that is loaded in the RF frequency band on the channel frequency, be reduced to medium-frequency band (IF; General be extensive use of 44MHz, but under the situation of analog television broadcast, then use 43.75MHz), and the signal of other channel of filtering positively.And, the spectrum transformation of arbitrary channel is become tuner 102 output signals of IF passband signal, will be by playing the surface acoustic wave SAW filter 103 of removing the neighboring trace signal and removing the noise signal function.At this moment, digital broadcast signal, for instance, because among the 6MHz of 44MHz intermediate frequency frequency band, exist all information, so SAW filter 103 is from the output of tuner 102, only stay the 6MHz frequency band that has information, and will have after remaining interval all removed, output to IF amplifier 104.
That is, the DC composition is to resume work in order to carry out carrier wave in the carrier wave recovery section, and is forced to be inserted in the transmission signal by transmitting terminal.So after finishing the carrier wave recovery, the DC composition that is inserted by transmitting terminal has not just needed yet.And DC remover 107 detects the DC composition, and it is got rid of from the baseband signal of carrier wave recovery section 106 outputs.
Remove the digital signal of DC composition base band afterwards, will output to equalizer portion 108 and channel equalizer 109.
Usually, the VSB load mode of the GA of U.S. HDTV Major Leagues suggestion is compared with other DTV load mode, and attractive properties can be thought pilot signal, data segment sync signal and field sync signal.These signals are all in order to improve that carrier wave recovers and characteristic such as hour hands recovery and being inserted and transmission by transmitting terminal.And equalizer portion 108 will restore data segment sync signal, the field sync signal of once inserting when sending from the signal of having removed DC.The synchronizing signal that so obtains will output to channel equalizer 109, phase compensator 110 and FEC portion 111.
At this moment, as shown in Figure 1, all after A/D converter 105 is converted into digital signal, will be output to carrier wave recovery section 106 through the signal of simulation process process.And if can not the reinsertion of carrier, all digital processing square frames of end after the carrier wave recovery section 106 so be all with cisco unity malfunction when carrier wave recovery section 106.And the carrier wave recovery section 106 in the DTV receiver is present in the position of transmitting the pilot carrier frequency on the signal frequency with restoring exactly, and it is converted to baseband signal.
Now, the prevailing algorithm of carrier wave recovery section 106 is as shown in Figure 2, will use a kind of so-called frequency phase lock ring FPLL (Frequency Phase Locked Loop), because its circuit is formed simple, excellent performance, so used widely.That is to say, the carrier wave recovery section of forming by FPLL 106, by the I in the passband of A/D converter 105 outputs, Q signal, demodulation becomes the I of base band, after the Q signal, goes locking frequency and phase place.
As shown in Figure 2, real number that be digitized in A/D converter 105, in the passband becomes sub-signal, is input to delayer 201 and Hilbert transformer 202.
Hilbert transformer 202 becomes sub-signal upset 90 degree to the real numbers (real) of input, and it is transformed into after the signal of imaginary number composition, outputs to complex multiplier 203.Delayer 201 then becomes sub-signal to the real number of input, with postpone a time required when being equivalent to handle in Hilbert transformer 202 after, outputs to complex multiplier 203 again.
For convenience of explanation, will call the I channel signals to signal, the signal through Hilbert transformer 202 will be called the Q channel signals through delayer 201.
The I of base band, Q signal when being output to DC remover 107, for the reinsertion of carrier, outputing to the 1st low pass filter 204 to the I signal of base band, and the Q signal of base band is outputed to the 2nd low pass filter 205.
At this moment, in the carrier wave recovery section 106 of the reinsertion of carrier, the ambient signals of pilot signal frequency that only need be in 6MHz.And in order to prevent to reduce owing to data the performance of carrier wave recovery section, the 1st, the 2nd low pass filter 204,205 will be removed the remaining frequencies composition that has data component from I in the Q signal.
The output of the 1st low pass filter 204 will be input to delayer 206.Delayer 206 postpones the I signal of having removed data component to output to symbol withdrawal device 207 after the certain hour.At this moment, the I signal from the pilot signal composition of the 1st low pass filter 204 outputs by delayer 206 time, if pilot signal can not be transformed into the DC composition exactly, so just is equivalent to take place respective phase error therewith.
And delayer 206 will become the poor of branch to the carrier frequency of pilot signal frequency content in the passband signal of input and digital controlled oscillator 210, be transformed into the form of phase error, the right symbol withdrawal device 207 that outputs to afterwards.
At this moment, be present in the passband, and as the pilot signal frequency of carrier signal composition if be transfused to, consistent exactly with the frequency content of the carrier signal that in digital controlled oscillator 210, takes place, its effect of carrier wave recovery section 106 that just is through with so.
As mentioned above, the pilot signal frequency is to be used and a reliable information of transmission as the reinsertion of carrier by transmitting terminal, and contingent phase jitter is also few when carrier wave recovers.But, as at urban environment, in the many channel environment of reflected wave,, recover to exist certain limit so it is used in carrier wave because the pilot signal in the received signal will reduce.That is,, have the situation that data component weakens, also have the situation that comprises the pilot signal frequency content that weakens along with DTV receiving channels environment; In the time of the most serious, also may the pilot signal composition simply not occurred owing to the frequency content that comprises pilot signal is attenuated to fully.
As mentioned above, if weakened or when simply the pilot signal composition not occurring, just can not finish carrier wave exactly and resume work.And, when pilot signal reduces, because of meeting is subjected to the more noise influence, with the degree of jitter of aggravation phase place.
Summary of the invention
The object of the invention is to provide a kind of the VSB conversion of signals is become after the offset orthogonal amplitude modulation OQAM signal aspect, removes to calculate the carrier centering device of carrier phase error.
Carrier centering device of the present invention, form by following structure, it is characterized in that: be provided with one VSB passband real number composition and imaginary number composition, after the complex carrier that is directly proportional with phase error multiplies each other respectively, the real number composition of VSB passband is become sub-signal with imaginary number, change into the real number composition of VSB base band and the complex multiplier of imaginary number composition; Be provided with a output, with after the frequency arbitrarily, the signal of VSB base band real number composition and imaginary number composition be modulated into OQAM real number composition become sub-signal with imaginary number, the VSB/OQAM transformation component of forming by complex multiplier with CM to complex multiplier; Also be provided with a utilization and become sub-signal with imaginary number, go to calculate the error reckoning portion of carrier phase error from the OQAM real number composition of VSB/OQAM transformation component output; Also be provided with one from the output of error reckoning portion, allow by hour hands after the frequency content that takes place is passed through, carry out the filter and the descending sampling portion of descending sampling; Also be provided with after the output to filter and descending sampling portion filters and accumulate, generate a complex carrier that is directly proportional with the value of accumulation, output to the filter and the oscillator of complex multiplier then.
Carrier centering device of the present invention can be modulated into the VSB signal after the OQAM signal, and the OQAM signal that utilization is modulated into removes to finish carrier wave and resumes work; Thereby under the VSB load mode, do not utilize pilot signal, also can finish resuming work of carrier wave exactly.Therefore, as under the abominable channel environment that many reflected waves are arranged the environment of down town,, also can finish accurately carrier wave and resume work even pilot signal is weakened or simply do not occur.
Description of drawings
Fig. 1 is the structured flowchart of ordinary numbers television receiver in the prior art.
Fig. 2 is the detailed diagram of carrier wave recovery section among Fig. 1.
Fig. 3 is in the present invention, the signal ordered state figure when the VSB signal is carried out quadrature amplitude modulation QAM modulation.
Fig. 4 is the graph of a relation between VSB signal of the present invention and the OQAM signal.
Fig. 5 is the structured flowchart of the carrier centering device of the 1st example of the present invention.
Fig. 6 is the structured flowchart of the carrier centering device of the 2nd example of the present invention.
Fig. 7 is the structured flowchart of the carrier centering device of the 3rd example of the present invention
Embodiment
Carrier centering device of the present invention, form by following structure, it is characterized in that: be provided with one VSB passband real number composition and imaginary number composition, after the complex carrier that is directly proportional with phase error multiplies each other respectively, the real number composition of VSB passband is become sub-signal with imaginary number, change into the real number composition of VSB base band and the complex multiplier of imaginary number composition; Be provided with a output, with after the frequency arbitrarily, the signal of VSB base band real number composition and imaginary number composition be modulated into OQAM real number composition become sub-signal with imaginary number, the VSB/OQAM transformation component of forming by complex multiplier with CM to complex multiplier; Also be provided with a utilization and become sub-signal with imaginary number, go to calculate the phase place reckoning portion of carrier phase error from the OQAM real number composition of VSB/OQAM transformation component output; Also be provided with one from the output of phase place reckoning portion, allow by hour hands after the frequency content that takes place is passed through, carry out the filter and the descending sampling portion of descending sampling; Also be provided with after the output to filter and descending sampling portion filters and accumulate, generate a complex carrier that is directly proportional with the value of accumulation, output to the filter and the oscillator of complex multiplier then.
Phase place reckoning portion has following characteristics, that is: the complex signal that contains VSB signal code composition from the OQAM signal is calculated carrier phase error.
Phase place reckoning portion also has following characteristics, that is: the complex signal that does not contain VSB signal code composition from the OQAM signal is calculated carrier phase error.
Phase place reckoning portion also has following characteristics, what export from the VSB/OQAM transformation component, goes to calculate phase error again after the real number composition of OQAM signal and imaginary number composition multiply each other that is:.
Phase place reckoning portion also has following characteristics, that is: to what export from the VSB/OQAM transformation component, the real number composition of OQAM signal and imaginary number composition are asked for respectively after the involution value, go to calculate phase error from the difference of two involution signals.
Phase place reckoning portion also has following characteristics, to what export from the VSB/OQAM transformation component, after the real number composition of OQAM signal and imaginary number composition take absolute value respectively, goes to calculate phase error from the difference of two absolute value signal that is:.
Below, the composition and the effect of example of the present invention are described with reference to accompanying drawing.
Carrier centering device of the present invention is that the VSB signal is modulated into after the OQAM signal, utilization comprises the real number of symbol composition and the signal of imaginary number composition in the OQAM signal, or do not comprise the real number composition and the imaginary number composition of symbol composition, remove to detect carrier phase error.
, have a look with reference to accompanying drawing 3 earlier for this reason, the VSB signal of base band is modulated into the process of OQAM signal.
Hypothesis VSB signal has carried out digitized processing with 2 times sampling frequency in A/D converter 105 earlier.So, shown in a of Fig. 3, the VSB signal in the middle of having one between the sampling of two symbols I1, the I2 sampling value X1 (that is, and I1, X1, I2, X3, I3, X5 ...).
At this moment, in the baseband I shown in a of Fig. 3, on the QVSB signal, with frequency exp (jwn) arbitrarily, just become and have the OQAM signal of being arranged as Fig. 3 b with CM.
In the VSB of Fig. 3 a signal,, turn over by Hilbert transformer and to turn 90 degrees the signal that generates, so on the b of Fig. 3, omitted sign to Q signal because Q signal is the phase place I signal.That is,, just can know Q signal so certainly, so omitted sign if as long as in the VSB signal, know I signal.
In addition, at the Yi of Fig. 3 b be, by the value arbitrarily that middle sampled signal in the VSB signal and Q signal produce, w then is a modulating frequency, and it will be corresponding to the value of 2.69MHz (that is π/4)., be OQAM here, so be modulated into the I signal of VSB as can be seen when the signal that comprises symbol is modulated into, will be to be distributed in the situation among real number and the imaginary number composition in a zigzag.
Fig. 4 shows the relation of VSB signal and OQAM signal in frequency band; Fig. 4 a shows the VSB signal, and Fig. 4 b then shows the OQAM signal.
Utilize two kinds of values to calculate carrier phase error in the present invention.One is in being modulated into the signal of OQAM, utilizes the complex signal of the symbol composition comprise the VSB signal, i.e. I1+jY1, Y4+jI2 ... situation; Another is the complex signal that utilizes the symbol composition that does not comprise the VSB signal, i.e. Y2+jY3, Y5+jY6 ... situation.
At this moment, utilize the signal comprise the signal of symbol or not comprise symbol to calculate carrier phase error, multiple mode can be arranged.In the present invention, will describe by the 1st to the 3rd example.
At first, the 1st example is after the signal of a real number composition that is modulated into OQAM and imaginary number composition is multiplied each other, the situation of removing to detect carrier phase error, and the details diagram is seen the block diagram of Fig. 5.
As shown in Figure 5, the 1st example is made up of following part, that is: be provided with one to passing through the VSB passband I that delayer 501 and Hilbert transformer 502 are exported, on the Q signal, after the complex carrier of CM with feedback, with the I of VSB passband, Q signal is transformed into the VSB baseband I, the 1st complex multiplier 503 of Q signal; Be provided with a VSB baseband I with the output of the 1st complex multiplier 503, Q signal is transformed into the 2nd complex multiplier 504 of OQAM signal with it with CM afterwards with frequency (jwn) arbitrarily; Also be provided with a multiplier 505 that becomes sub-signal to be multiplied each other with imaginary number the real number composition of the 2nd complex multiplier 504 outputs; Also be provided with the band pass filter 506 that a clock that allows multiplier 505 product signals gives passing through along the frequency content that generates; Also be provided with a frequency content, carry out after the descending sampling, make its descending sampling portion 507 to the DC position transfer to band pass filter 506 output; Also be provided with a output, the loop filter 508 that filters and accumulate to descending sampling portion 507; And also be provided with after the complex carrier that a generation is proportional to loop filter 508 output, output to the digital controlled oscillator NCO509 of the 1st complex multiplier 503.
The present invention's the 1st example that below explanation is had said structure, in being modulated into the signal of OQAM, utilize the complex signal comprise VSB signal code composition (that is, and I1+jY1, Y4+jI2 ...), calculate the situation of carrier phase error.
That is, if to the VSB baseband I from the output of the 1st complex multiplier 503, Q signal multiply by plural number (exp (jwn), the w=of optional frequency
π/4), so just the same with the b of Fig. 4, the center of frequency band VSB signal will be moved to DC, and become the OQAM signal.
Here, only the complex signal that comprises the symbol composition of VSB signal (that is, and I1+jY1, Y4+jI2 ...) output to second complex multiplier 504.
At this moment, in the signal of supposing to import carrier phase error (θ) is arranged, the signal that is input to multiplier 504 so is for shown in mathematical expression 1.
Mathematical expression 1:
(I1+jY1)(expjθ)＝(I1*cosθ-Y1*sinθ)+j(I1*sinθ+Y1*cosθ)
In mathematical expression 1, the real number composition is called I1 (=I1*cos θ-Y1*sin θ), the imaginary number composition is called Q1 (=I1*sin θ+Y1*cos θ), if then with two signal I1, Q1 multiplies each other in multiplier 505, so just becomes shown in mathematical expression 2.
Mathematical expression 2:
I1*Q1＝1/2(I1
2-Y1
2)*sin2θ+I1*Y1*cos2θ
From mathematical expression 2 as can be known, there are two kinds of compositions in the formula; Wherein, the I1*Y1 composition is because the value that produces by pilot signal or data is very little, so very faint to calculating the carrier phase influence.And (I1
2-Y1
2) * sin2 θ, then irrelevant with pilot signal, calculate carrier phase but will influence.At this, (I1
2-Y1
2) will determine the size of carrier phase error, and sin2 θ will determine the direction of carrier phase error.That is, sin2 θ also becomes negative when θ is negative, therefore turns to forward to get final product carrier phase; When θ is positive number, then turn to negative sense to get final product carrier phase.
At this moment, the output of multiplier 505 will output to band pass filter 506; See typical figure 5: band pass filter 506, with go to filter one by by the product signal clock of the I1 of OQAM signal and Q1 along 401 frequency contents that generate, output to descending sampling portion 507 then.Descending sampling portion 507 in addition after the descending sampling, only outputs to loop filter 508 to the output of band pass filter 506 to the signal of desired location.
At this, the position of clock along 401 is 2.69MHz in ideal conditions.In addition, in multiplier 505, when two signals of the real number composition of OQAM signal and imaginary number composition are multiplied each other, will call tone tone to it by clock along a kind of frequency content of 401 generations; Tone produces at the 5.38MHz place in ideal conditions.And band pass filter 506 will go to the position of filtering 5.38MHz.If band pass filter 506 carries out filtering, and descending sampling portion 507 carries out descending sampling, so just can obtain the signal on the desired location, and this signal is output to loop filter 508.That is to say that the signal from 507 outputs of descending sampling portion will become carrier phase error.Loop filter 508 will output to digital controlled oscillator NCO509 after will filtering, accumulate the output of descending sampling portion 507.Digital controlled oscillator NCO509 will generate with loop filter 508 and be output into after the complex carrier of direct ratio, output to the 1st complex multiplier 503.If the repetition said process will produce in digital controlled oscillator NCO509 and the almost similar carrier frequency signaling of signal(-) carrier frequency composition that is transfused to so, and it is outputed to the 1st complex multiplier 503.The 1st complex multiplier 503 will change into a required baseband vsb signal to the VSB signal of passband.
Fig. 6 is the structured flowchart of the carrier centering device of the present invention's the 2nd example.This example is in the OQAM signal of the 2nd complex multiplier 604 output, with the signal of real number composition and imaginary number composition, carries out respectively after the involution, detects carrier phase error from the involution difference of two signals.
In Fig. 6, utilize involution portion 605 and subtracter 606, go from the OQAM signal, to detect carrier phase error after the multiplier in the alternate figures 5.Remaining composition, as delayer 601, Hilbert transformer 602, the 1 complex multipliers 603, band pass filter 607, descending sampling portion 608, loop filter 609, and NCO610 etc., all have identical structure, and go to finish identical work, an is-symbol difference with Fig. 5.
To the 2nd example of the present invention with this structure be described below.This example is in the signal of OQAM modulation, utilize the complex signal that do not comprise VSB signal code composition (that is, and Y2+jY3, Y5+jY6 ...), go to calculate the situation of carrier phase error.
That is, if to the VSB baseband I of the 1st complex multiplier 603 output, Q signal multiply by the plural number of frequency (exp (jwn), w=π/4) arbitrarily, and so as shown in Figure 4, the center of VSB signal will move to DC from frequency band, and become the OQAM signal.
With do not comprise in the OQAM signal VSB signal code composition complex signal (that is, and Y2+jY3, Y5+jY6 ...) output to involution portion 605.At this moment,, so, be input to the signal of involution portion 605 if in the signal of hypothesis input carrier phase error (θ) is arranged, will be shown in mathematical expression 3.
[mathematical expression 3]
(Y2+jY3)(expjθ)＝(Y2*cosθ-Y3*sinθ)+j(Y2*sinθ+Y3*cosθ)
In mathematical expression 3, the real number composition is called I2 (=Y2*cos θ-Y3*sin θ), and the imaginary number composition is called Q2 (=Y2*sin θ+Y3*cos θ); If with two signal I2, the difference of two values is obtained in respectively in addition involution in the device of involution separately of Q2 in involution portion (605) then in (606), so just become an expression formula shown in mathematical expression 4.
[mathematical expression 4]
I2
2-Q2
2＝(Y2
2-Y3
2)*sin2θ+2*Y2*Y3*cos2θ
From mathematical expression 4 as can be known, there are two kinds of compositions in the formula; Y2 wherein
2-Y3
2Composition is the value that is produced by pilot signal or data, and this value is very little, so very faint to calculating the carrier phase influence.And the Y2*Y3 value is irrelevant with pilot signal, but to calculating that carrier phase has decisive influence.
At this, Y2*Y3 will determine the size of carrier phase error, and cos2 θ will determine the direction of carrier phase error.
In like manner, the output of subtracter 606 will output to band pass filter 607; Band pass filter 607 will go to filter one by by to the clock of the involution signal subtraction difference of the power of the I2 of OQAM signal and Q2 along 401 frequency contents that produced, will output to descending sampling portion 608 then.The output of 608 pairs of band pass filters 607 of descending sampling portion is carried out after the descending sampling, only the signal of desired location is outputed to loop filter 609.Loop filter (609) outputs to NCO (610) after the output of descending sampling portion (608) is filtered, accumulated.NCO (610) will generate after the complex carrier that is output into direct ratio with loop filter (609), output to the 1st complex multiplier (601).
Fig. 7 is the structured flowchart of the carrier centering device of the present invention's the 3rd example.This example is to the real number composition in the OQAM signal of the 2nd complex multiplier (604) output and the signal of imaginary number composition, carries out respectively after the signed magnitude arithmetic(al), detects carrier phase error from the difference of two absolute value signal.
In Fig. 7, taking advantage of the quadrate part (605) in utilizing absolute value calculation portion (705) alternate figures 6 has identical structure with Fig. 6, and goes to finish identical work.
That is, absolute value calculation portion (705) after taking absolute value respectively, outputs to subtracter (706) to from the OQAM real number composition of the 2nd complex multiplier (704) output and the signal of imaginary number composition.Subtracter (706) is obtained after the difference of two absolute value calculation portions, outputs to band pass filter (707).
Later working condition, identical with above-mentioned Fig. 5 and Fig. 6, so will omit detailed explanation.
As mentioned above, the present invention will be in the OQAM signal, comprising the complex signal of VSB signal code composition, and is suitable for some in the 1st to the 3rd above-mentioned example and can calculates carrier phase; Also can be in the OQAM signal, not comprising the complex signal of symbol composition, and be suitable for some in above-mentioned the 1st to the 3rd example, remove to calculate carrier phase error.
By above-mentioned explanation, if the people of the industry can both know under the situation that does not break away from technological thought scope of the present invention, diversified change and correction to be arranged.According to the explanation that above-mentioned diagram is done, be an example to composition of the present invention and effect; Technological thought of the present invention, core texture and effect will can not be subjected to the qualification of example content.
Claims (8)
1, a kind of carrier centering device, have following function: this device will receive the data with the modulation system transmission of residual sideband VSB, and it is carried out digitized processing, to be digitized the signal phase upset an angle of 90 degrees of the VSB passband real number composition of processing then, generate imaginary number and become sub-signal, calculate carrier phase error with these two signals again; It is characterized in that:
Be provided with one the real number composition of VSB passband and imaginary number become sub-signal with and after the complex carrier that is directly proportional of phase error multiplies each other respectively, the real number composition of VSB passband is become the real number composition of VSB base band and the 1st complex multiplier of imaginary number composition with imaginary number composition conversion of signals;
Be provided with a output to the 1st complex multiplier, with CM with after the frequency arbitrarily, the signal of VSB base band real number composition and imaginary number composition is modulated into OQAM real number composition becomes sub-signal with imaginary number, the VSB/OQAM transformation component of forming by the 2nd complex multiplier;
Also be provided with a utilization and become sub-signal with imaginary number, go to calculate the phase place reckoning portion of carrier phase error from the OQAM real number composition of VSB/OQAM transformation component output;
Also be provided with one from the output of phase place reckoning portion, allow by hour hands after the frequency content that takes place is passed through, carry out the filter and the descending sampling portion of descending sampling;
Also be provided with after the output to filter and descending sampling portion filters and accumulate, generate a complex carrier that is directly proportional with the value of accumulation, output to the filter and the oscillator of the 1st complex multiplier then.
2, carrier centering device according to claim 1 is characterized in that in the VSB/OQAM transformation component, is π/4 to the signal times of VSB base band real number and imaginary number composition with the frequency arbitrarily of plural number.
3, carrier centering device according to claim 1, the VSB signal that it is characterized in that the 1st complex multiplier be by 2 times symbol frequency digitlization, and in the middle of having one between two sampling symbols sampling values.
4, carrier centering device according to claim 1 is characterized in that phase place reckoning portion contains the complex signal of VSB signal code composition and calculate carrier phase error from the OQAM signal.
5, carrier centering device according to claim 1 is characterized in that phase place reckoning portion does not contain VSB signal code composition from the OQAM signal complex signal calculates carrier phase error.
6, carrier centering device according to claim 1 is characterized in that phase place reckoning portion from VSB/OQAM transformation component output, goes to calculate phase error after the real number composition of OQAM signal and imaginary number composition multiply each other again.
7, carrier centering device according to claim 1, it is characterized in that phase place reckoning portion is to from VSB/OQAM transformation component output, the real number composition of OQAM signal and imaginary number composition are asked for respectively after the involution value, go to calculate phase error from the difference of two involution signals.
8, carrier centering device according to claim 1, it is characterized in that phase place reckoning portion is to from VSB/OQAM transformation component output, after the real number composition of OQAM signal and imaginary number composition take absolute value respectively, go to calculate phase error from the difference of two absolute value signal.
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| CNB031340695A CN100340109C (en) | 2003-09-26 | 2003-09-26 | Carrier reset device |
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| CNB031340695A CN100340109C (en) | 2003-09-26 | 2003-09-26 | Carrier reset device |
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| US7706474B2 (en) * | 2005-11-14 | 2010-04-27 | Ibiquity Digital Corporation | Carrier tracking for AM in-band on-channel radio receivers |
| CN102082938B (en) * | 2009-11-30 | 2013-03-27 | 展讯通信（上海）有限公司 | Analog television detection apparatus and method for the same |
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