CN1236513A - Quadrature frequency division multiplexing remodulator - Google Patents
Quadrature frequency division multiplexing remodulator Download PDFInfo
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- CN1236513A CN1236513A CN98801089A CN98801089A CN1236513A CN 1236513 A CN1236513 A CN 1236513A CN 98801089 A CN98801089 A CN 98801089A CN 98801089 A CN98801089 A CN 98801089A CN 1236513 A CN1236513 A CN 1236513A
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Abstract
A quadrature frequency division multiplexing demodulator, wherein a differential detection circuit (26) performs differential detection with respect to symbols on the output of an FFT circuit (25), a correlation calculating circuit (27) calculates the correlative values between the outputs of the differential detection and the allocation information of subcarriers for pilot signal, then a broad-band carrier frequency error calculating circuit (28) calculates the frequency error in each subcarrier interval from the peaks of the correlated values, and a carrier frequency correcting circuit (23) corrects a carrier frequency by using the frequency errors. In addition, a phase averaging circuit (29) averages the phases of the outputs of the differential detection corresponding to the subcarriers for pilot signal, and a phase variation correcting circuit (30) corrects the phase variation common to all subcarriers. Thus, carrier frequency synchronization having a short drawing time can be realized and, at the same time, a phase variation that is common to all subcarriers caused by the phase noise, etc., of a tuner can be removed.
Description
The present invention relates to be used for the digital broadcasting undertaken by orthogonal frequency-division multiplex transmission system and the orthogonal frequency division complex signal demodulator of digital communication, particularly relate to the recipient and be used for the Frequency Synchronization technology of playback carrier wave of demodulation and the technology of eliminating the influence of common phase place change at the whole subcarriers that produced by the phase noise of tuner etc.
In recent years, in the digital television broadcasting of broadcasting of the digital audio of moving body and ground system, OFDM (hereinafter referred to as OFDM (Orthogonal Frequency DivisionMultiplex)) transmission means is especially noticeable.
This OFDM transmission means is such mode: modulate mutually orthogonal a plurality of subcarriers by the numerical data of transmitting, multiplexing these modulating waves transmit.This mode has such feature: when the quantity of the subcarrier that uses when hundreds of becomes several thousand because the code-element period of each modulating wave becomes very long, then be easy to be subjected to the influence that multipath disturbs.
Use Fig. 1 that the principle of OFDM transmission means is described below.
Fig. 1 is the block diagram that the principle of expression OFDM transmission means constitutes.And in Fig. 1, thick-line arrow is represented complex signal, and thin-line arrow is represented real number signal.
At first, at transmit leg, be transmitted signal be input in the ofdm signal modulating device 11 data-signal by mapping circuit 111 be mapped as with the corresponding complex number plane of the modulation system of each subcarrier on signaling point, then, offer inverse fourier transform (hereinafter referred to as IFFT (InverseFast Fourier Transform)) circuit 112.The signal that is transmitted of 112 pairs of code elements of this IFFT circuit carries out the IFFT processing; generate the effective code element time signal by being transformed to time zone; and; in each code element; the rear portion of effective code element time signal as the guard period signal; and be attached to before the effective code element time signal, thus, have the function of the ofdm signal that generates base band.The baseband OFDM signal that is wherein generated is provided for quadrature modulation circuit 113.These quadrature modulation circuit 113 usefulness baseband OFDM signals carry out quadrature modulation to carrier wave, thus, is this baseband OFDM signal frequency conversion the signal of intermediate frequency (hereinafter referred to as IF (IntermediateFrequency)) frequency band, the ofdm signal of this IF frequency band is the signal of radio frequency (hereinafter referred to as RF (Radio Frequency)) frequency band by upconverter 114 frequency conversions, exports to transmission line 12.
On the other hand, the recipient, the ofdm signal that is input to the OFDM demodulating equipment 13 from transmission line 12 is the IF frequency band by tuner 131 from the frequency conversion of RF frequency band, then, offers orthogonal demodulation circuit 132.Carry out quadrature modulation by 132 pairs of IF band signals of being imported of this orthogonal demodulation circuit, and be demodulated into the baseband OFDM signal, this demodulation output is provided for Fourier transform (hereinafter referred to as FFT (Fast Fourier Transform)) circuit 133.This fft circuit 133 takes out the effective code element time signal and carries out the FFT processing from the baseband OFDM signal, and is transformed to frequency field, and this output is provided for detecting circuit 134.This detecting circuit 134 comes each subcarrier is carried out detection according to modulation system, then, and the restored data signal by carrying out inverse mapping.
But, in above-mentioned such principle constitutes, when having error between the frequency that is sending the carrier wave that uses in receiving, demodulating data correctly.Therefore, in the prior art, disclosed such measure: subcarrier interval two automatic frequency control (hereinafter referred to as AFC (Auto Frequency Control)) circuit with interior and subcarrier interval unit are made up, the Frequency Synchronization that obtains wide region (for example, the original text collection is given in Communications Society of electronic information communication association in 1996 conference, B-512, the 512nd page).
In the AFC mode that in above-mentioned document, is disclosed, be the duplicating of rear portion of effective code element time signal because of the guard period signal in the ofdm signal, and utilize the relation between them to calculate subcarrier interval with interior frequency error.Use the reference symbol of using with the Frequency Synchronization that predetermined period was inserted to calculate the frequency error of subcarrier interval unit at transmit leg.
Use Fig. 2 and Fig. 3 to come the formation and the action of the existing ofdm signal demodulating equipment that uses the AFC mode that above-mentioned document discloses are described below.
Fig. 2 is the ideograph of expression Frequency Synchronization with an example of the formation of reference symbol.In Fig. 2, transverse axis is represented frequency, and the longitudinal axis is represented amplitude, and the solid line among the figure is illustrated in this frequency and has subcarrier, and dotted line is illustrated in and does not have subcarrier in this frequency.In this embodiment, make having or not of subcarrier corresponding with predetermined pseudorandom (hereinafter referred to as PN (Pseudo Noise)) series.
Fig. 3 is the block diagram of the formation of the existing ofdm signal demodulating equipment of expression.In Fig. 3, thick-line arrow is represented complex signal, and thin-line arrow is represented real number signal.And omitted general control signal such as needed clock in the action of each component parts, so that illustrate uncomplicated.
In Fig. 3, tuner 21 is the ofdm signal of importing from transmission line the IF frequency band from the RF frequency band transformation, and its output is transfused to orthogonal demodulation circuit 22.This orthogonal demodulation circuit 22 uses the fixed carrier of portion's generation within it that the ofdm signal of IF frequency band is demodulated into the baseband OFDM signal, and this demodulation output is provided for the first input end of carrier frequency (fc) correcting circuit 23.This carrier frequency correcting circuit 23 multiply by the baseband OFDM signal that offers first input end to the broadband carrier wave error signal according to the subcarrier interval unit that offers second input with the subcarrier interval that offers the 3rd input with the correction carrier wave that interior narrow-band carrier frequency error signal takes place, thus, proofread and correct carrier frequency error, its output is provided for narrow-band carrier frequency error counting circuit 24 and fft circuit 25.
Narrow-band carrier frequency error counting circuit 24 utilizes the correlation at the rear portion of guard period signal in the baseband OFDM signal and effective code element time signal; calculate subcarrier interval with interior frequency error, its output is provided for the 3rd input of carrier frequency correcting circuit 23.Effective code element time signal in 25 pairs of baseband OFDM signals of fft circuit is carried out the FFT processing, is transformed to frequency field, and its output is provided for power calculation circuit 41 and detecting circuit 31.
This power calculation circuit 41 calculates and the corresponding signal power of being exported from fft circuit 25 of each subcarrier, and its result of calculation is provided for correlation calculations circuit 42.This correlation calculations circuit 42 calculate power calculation circuit 41 output and with the correlation that has or not corresponding PN series of the subcarrier of Frequency Synchronization reference symbol shown in Figure 22, this correlation is provided for broadband carrier frequency error counting circuit 28.This broadband carrier frequency error counting circuit 28 is calculated the frequency error of subcarrier interval unit from the peak of correlation, and its output is provided for second input of carrier frequency correcting circuit 23.Detecting circuit 31 comes each subcarrier is carried out detection according to modulation system, then, restores data-signal by carrying out inverse mapping.
But, in above-mentioned existing method,, calculate the frequency error of subcarrier interval unit at the reference symbol that transmit leg uses the Frequency Synchronization inserted with predetermined period (for example frame) to use, therefore, the introducing time of Frequency Synchronization becomes longer.
In existing method,, then need the time constant of the loop filter that is located at narrow-band carrier frequency error counting circuit 24 inside of for example Fig. 3 is set at hundreds of symbol times owing to reduced the error of the carrier frequency under the normal condition.Therefore, can not follow the tracks of the rapid change (be not limited in this example, in general A FC circuit, can not follow the tracks of the rapid change of the phase noise etc. of tuner) of the phase noise etc. of tuner.Thus, this residual frequency error has caused interference (hereinafter referred to as ICI (Inter Carrier Interference)) and the common phase place change (hereinafter referred to as CPE (Common Phase Error)) in whole subcarriers between the subcarrier, and becomes the principal element that error rate worsens.
Therefore,, the purpose of this invention is to provide a kind of ofdm signal demodulating equipment, can further shorten the time of Frequency Synchronization, and remove influence by the caused CPE such as phase noise of tuner in order to address the above problem.
In order to address the above problem, OFDM transmission means involved in the present invention is following such formation:
(1) a kind of device of demodulation orthogonal frequency-division multiplex singal, this orthogonal frequency-division multiplex singal is included in first pilot signal that is disposed in the frequency identical with each code element, it is characterized in that, comprise: Fourier transform device, by above-mentioned orthogonal frequency-division multiplex singal is carried out Fourier transform, and be transformed to the frequency axis signal; The differential detection device carries out differential detection between code element by the output to above-mentioned Fourier transform device, calculates the change between code element; The correlation calculations device is calculated the correlation of the output of the configuration information of above-mentioned first pilot signal and above-mentioned differential detection device; Broadband carrier frequency error calculation element, the peak of the output by detecting above-mentioned correlation calculations device is determined the carrier frequency error of subcarrier interval unit; Broadband carrier frequency means for correcting is proofreaied and correct carrier frequency according to the output of above-mentioned broadband carrier frequency error calculation element.
(2) a kind of device of demodulation orthogonal frequency-division multiplex singal, this orthogonal frequency-division multiplex singal is included in first pilot signal that is disposed in the frequency identical with each code element, it is characterized in that, comprise: Fourier transform device, by above-mentioned orthogonal frequency-division multiplex singal is carried out Fourier transform, and be transformed to the frequency axis signal; The differential detection device carries out differential detection between code element by the output to above-mentioned Fourier transform device, calculates the change between code element; The phase average device averages the output phase with the corresponding above-mentioned differential detection device of above-mentioned first pilot signal in code element, determine phase place change common in whole subcarriers thus; Phase place change means for correcting from the correcting vector that each code element is calculated in the output of above-mentioned phase average device, according to above-mentioned correcting vector, is proofreaied and correct phase place change common in whole subcarriers.
(3) a kind of device of demodulation orthogonal frequency-division multiplex singal, this orthogonal frequency-division multiplex singal is included in first pilot signal that is disposed in the frequency identical with each code element, it is characterized in that, comprise: Fourier transform device, by above-mentioned orthogonal frequency-division multiplex singal is carried out Fourier transform, and be transformed to the frequency axis signal; The differential detection device carries out differential detection between code element by the output to above-mentioned Fourier transform device, calculates the change between code element; The correlation calculations device is calculated the correlation of the output of the configuration information of above-mentioned first pilot signal and above-mentioned differential detection device; Broadband carrier frequency error calculation element, the peak of the output by detecting above-mentioned correlation calculations device is determined the carrier frequency error of subcarrier interval unit; Broadband carrier frequency means for correcting is proofreaied and correct carrier frequency according to the output of above-mentioned broadband carrier frequency error calculation element; The phase average device averages the output phase with the corresponding above-mentioned differential detection device of above-mentioned first pilot signal in code element, determine phase place change common in whole subcarriers thus; Phase place change means for correcting from the correcting vector that each code element is calculated in the output of above-mentioned phase average device, according to above-mentioned correcting vector, is proofreaied and correct phase place change common in whole subcarriers.
(4) in the formation of (1) and (3), above-mentioned correlation calculations device is calculated the configuration information (2 value signal) of above-mentioned first pilot signal and the size of the correlation of the output (complex vector signal) of above-mentioned differential detection device.
(5) in the formation of (1) and (3), above-mentioned correlation calculations device is calculated the configuration information (2 value signal) of above-mentioned first pilot signal and the size of the correlation of the signal (complex signal) that the output of above-mentioned differential detection device is averaged on the code element direction.
(6) in the formation of (1) and (3), above-mentioned correlation calculations device is calculated the configuration information (2 value signal) of above-mentioned first pilot signal and the correlation of the size (real number signal) of the signal that the output of above-mentioned differential detection device is averaged on the code element direction.
(7) in the formation of (1) and (3), the configuration information (2 value signal) that above-mentioned correlation calculations device is calculated above-mentioned first pilot signal carries out the correlation that size is relatively carried out the signal (2 value signal) of 2 values with the size of the signal that the output of above-mentioned differential detection device is averaged with predetermined threshold on the code element direction.
(8) in the formation of (7), above-mentioned correlation calculations device is controlled above-mentioned threshold value by the size of received signal.
(9) in the formation of (1) and (3), above-mentioned broadband carrier frequency means for correcting is controlled the local frequency of tuner according to the output of above-mentioned broadband carrier frequency error calculation element.
(10) in the formation of (1) and (3), above-mentioned broadband carrier frequency means for correcting is controlled the local frequency of orthogonal demodulation device according to the output of above-mentioned broadband carrier frequency error calculation element.
(11) in the formation of (1) and (3), above-mentioned broadband carrier frequency means for correcting generates the correction carrier wave according to the output of above-mentioned broadband carrier frequency error calculation element, this correction carrier wave be multiply by the input signal of above-mentioned Fourier transform device.
(12) in the formation of (1); above-mentioned broadband carrier frequency means for correcting is according to the output of above-mentioned broadband carrier frequency error calculation element; the output signal occurrence frequency of above-mentioned Fourier transform device is moved; simultaneously, the phase place of proofreading and correct between the code element that depends on guard period length and take place changes.
(13) in the formation of (3), above-mentioned broadband carrier frequency means for correcting moves the output signal occurrence frequency of above-mentioned Fourier transform device according to the output of above-mentioned broadband carrier frequency error calculation element.
(14) in the formation of (2) and (3), above-mentioned phase place change means for correcting is packed in the detector arrangement, this detector arrangement is proofreaied and correct phase place change common in whole subcarriers according to the output of above-mentioned correcting vector calculation element, simultaneously, carry out detection according to the primary modulation mode of each subcarrier.
(15) in the formation of (14), a kind of device of demodulation orthogonal frequency division multiplexing signal is provided, this orthogonal frequency division multiplexing signal is on the basis of above-mentioned first pilot signal, be transmitted in the subcarrier symbol zone and disperse and second pilot signal of cycle configuration, it is characterized in that, above-mentioned detector arrangement is proofreaied and correct phase place change common in whole subcarriers according to the output of above-mentioned correcting vector calculation element, simultaneously, uses above-mentioned second pilot signal to come each subcarrier of synchronous detection.
(16) in the formation of (14), a kind of device of demodulation orthogonal frequency division multiplexing signal is provided, this orthogonal frequency division multiplexing signal is that the differential modulation that data-signal carries out between code element is transmitted, it is characterized in that, above-mentioned detector arrangement is proofreaied and correct phase place change common in whole subcarriers according to the output of above-mentioned correcting vector calculation element, simultaneously, each subcarrier is carried out differential detection between code element.
(17) in the formation of (2) and (3), above-mentioned phase average device handle averages in code element with the output complex vector of the corresponding above-mentioned differential detection device of above-mentioned first pilot signal, calculate its phase place, determine phase place change common in whole subcarriers thus.
(18) in the formation of (3), above-mentioned correlation calculations device comprises above-mentioned phase average device, calculate correlation by 2 the value signals configuration information that is produced and the complex vector signal of being exported from above-mentioned differential detection device of above-mentioned first pilot signal, offer above-mentioned broadband carrier frequency error calculation element, simultaneously, from determining common phase place change whole subcarriers by the phase angle of the resulting vector of above-mentioned correlation calculations, and offer above-mentioned phase place change means for correcting.
(19) in (1) to the formation of (18), above-mentioned first pilot signal comprises with the identical phase place of each code element modulates the signal that is configured in the sets of subcarriers in the identical frequency of each code element.
(20) in the formation of (1), (3) to (13), (18), when above-mentioned first pilot signal comprises being configured in sets of subcarriers in the identical frequency of each code element when carrying out the signal of m phase PSK modulation (m is a natural number), further comprise a times quadrupler, m is carried out in the output of above-mentioned differential detection device doubly take advantage of, offer above-mentioned correlation calculations device.
(21) in (2), (3), (14) to the formation of (18), when above-mentioned first pilot signal comprises being configured in sets of subcarriers in the identical frequency of each code element when carrying out the signal of m phase PSK modulation (m is a natural number), further comprise: times quadrupler, m is carried out in the output of above-mentioned differential detection device doubly take advantage of, offer above-mentioned phase average device; Coefficient unit multiply by 1/m to the output of above-mentioned phase average device doubly.
(21) in (2), (3), (14) to the formation of (18), when above-mentioned first pilot signal comprises being configured in sets of subcarriers in the identical frequency of each code element when carrying out the signal of m phase PSK modulation (m is a natural number), further comprise the vector whirligig, whether the output of judging above-mentioned differential detection device is included in by phase place is divided in any zone in complex number plane zone of m, come the output complex vector of above-mentioned differential detection device is rotated the integral multiple of 2 π/m according to this result of determination, thus, postrotational phase place is included in the identical zone all the time, then, offer above-mentioned phase average device.
These and other purpose, advantage and feature of the present invention will be in conjunction with the drawings to the description of embodiments of the invention and further specified.In these accompanying drawings:
Fig. 1 is the block diagram of formation of the principle of expression OFDM transmission means;
Fig. 2 is the ideograph of expression Frequency Synchronization with an example of the formation of reference symbol;
Fig. 3 is the block diagram of the formation of the existing ofdm signal demodulating equipment of expression;
Fig. 4 is the ideograph of expression pilot signal configuration example involved in the present invention;
Fig. 5 is the block diagram of the formation of the ofdm signal demodulating equipment in the expression first embodiment of the present invention;
Fig. 6 is the block diagram of the inside configuration example of the differential detection circuit in the presentation graphs 5;
Fig. 7 is the block diagram of the first inner configuration example of the correlation calculations circuit in the presentation graphs 5;
Fig. 8 is the block diagram of the second inner configuration example of the correlation calculations circuit in the presentation graphs 5;
Fig. 9 is the block diagram of the inside configuration example of filter circuit between code element in the presentation graphs 8;
Figure 10 is the block diagram of the 3rd inner configuration example of the correlation calculations circuit in the presentation graphs 5;
Figure 11 is the block diagram of the 4th inner configuration example of the correlation calculations circuit in the presentation graphs 5;
Figure 12 is the block diagram of the inside configuration example of the phase place change correcting circuit in the presentation graphs 5;
Figure 13 is the block diagram of the formation of the ofdm signal demodulating equipment in the expression second embodiment of the present invention;
Figure 14 is the block diagram of the formation of the ofdm signal demodulating equipment in the expression third embodiment of the present invention;
Figure 15 is the block diagram of the formation of the ofdm signal demodulating equipment in the expression fourth embodiment of the present invention;
Figure 16 is the block diagram of the formation of the ofdm signal demodulating equipment in the expression fifth embodiment of the present invention;
Figure 17 is the block diagram of the first inner configuration example of the detecting circuit among expression Figure 16;
Figure 18 is the block diagram of the second inner configuration example of the detecting circuit among expression Figure 16;
Figure 19 is the block diagram of the formation of the ofdm signal demodulating equipment in the expression sixth embodiment of the present invention;
Figure 20 is the block diagram of the inside configuration example of the correlation calculations circuit among expression Figure 19;
Figure 21 is the block diagram of the formation of the ofdm signal demodulating equipment in the expression seventh embodiment of the present invention;
Figure 22 is the block diagram of the formation of the ofdm signal demodulating equipment in the expression eighth embodiment of the present invention.
Below, as OFDM transmission means involved in the present invention, in the 2k mode (number of subcarriers that is used to transmit is 1705) of DVB-T (Digital Video Brosdcasting-Terrestrial) standard as the surface wave digital television broadcasting standard in Europe be example, and use Fig. 4 to Figure 22 comes embodiments of the invention are described.
In above-mentioned standard, use predetermined subcarrier, transmit scattered pilot (hereinafter referred to as SP (Scattered Pilots)) and two kinds of pilot signals of continuous pilot (hereinafter referred to as CP (Continual Pilots)).
Fig. 4 is the ideograph of the pilot signal configuration example of the above-mentioned DVB-T standard of expression.In Fig. 4, the index of the k vice carrier wave of transverse axis, the n of the longitudinal axis represents the index of code element.Filled circles represents to transmit the subcarrier of pilot signal, and open circles represents to transmit the subcarrier of other data.
Scattered pilot uses the index k=k that satisfies following (1) formula
pSubcarrier transmit.In (1) formula, mod represents the complementation computing, and p is a nonnegative integer arbitrarily.
k
p=3(n?mod4)+12
Continuous pilot is used and is satisfied k={0,48,54,87,141,156,192,201,255,279,282,333,432,450,483,525,531,618,636,714,759,765,780,804,873,888,918,939,942,969,984,1050,1101,1107,1110,1137,1140,1146,1206,1269,1323,1377,1491,1683,45 subcarriers of 1704} transmit.
These pilot signals bases and the corresponding PN series of the subcarrier index k of configuration respectively W
kModulate, shown in (2) formula like that, multiplexing with the amplitude that each code element is identical with identical phase place.In (2) formula, Re{c
K, nThe representative with the subcarrier index be that k, code element index are the corresponding complex vector c of subcarrier of n
K, nReal part, Im{c
K, nRepresent imaginary part.
In above-mentioned standard, use predetermined subcarrier to transmit parameter signals (hereinafter referred to as TPS (Transmission Parameter Signaling).TPS uses and satisfies k={34, and 50,209,346,413,569,595,688,790,901,1073,1219,1262,1286,1469,1594,17 subcarriers of 1687} transmit identical information bit.
At this moment, be that to carry out the information transmitted bit be S for the code element of n when making with the index
nThe time, as figure shown in (3) like that, the differential 2 value PSK (Phase ShiftKeying) that TPS is carried out between code element modulate.
But, relevant with the stem code element (code element index n=0) of frame, as figure shown in (4) like that, according to above-mentioned PN series W
kCarry out the absolute phase modulation.
(first embodiment)
Fig. 5 is the block diagram of the formation of the ofdm signal demodulating equipment in the expression first embodiment of the present invention.In Fig. 5, the part identical with Fig. 3 uses identical label to represent.And in the figure, the arrow of thick line is represented complex signal, and the arrow of fine rule is represented real number signal.Omitted needed clock etc. in the action of each component parts for the purpose of simplifying the description.
In Fig. 5, tuner 21 is the ofdm signal of importing from transmission line the IF frequency band from the RF frequency band transformation, and its output is transfused to orthogonal demodulation circuit 22.This orthogonal demodulation circuit 22 uses the fixed carrier of portion's generation within it that the ofdm signal of IF frequency band is demodulated into the baseband OFDM signal, and this demodulation output is provided for the first input end of carrier frequency (fc) correcting circuit 23.
This carrier frequency correcting circuit 23 is proofreaied and correct carrier wave with the subcarrier interval that offers the 3rd input with interior narrow-band carrier frequency error signal according to the broadband carrier wave error signal of the subcarrier interval unit that offers second input, this correction carrier wave be multiply by the baseband OFDM signal that offers first input end, thus, proofread and correct carrier frequency error, its output is provided for narrow-band carrier frequency error counting circuit 24 and fft circuit 25.
Narrow-band carrier frequency error counting circuit 24 utilizes the correlation at the rear portion of guard period signal in the baseband OFDM signal and effective code element time signal; calculate subcarrier interval with interior frequency error, its output is provided for the 3rd input of carrier frequency correcting circuit 23.Effective code element time signal in 25 pairs of baseband OFDM signals of fft circuit is carried out the FFT processing, is transformed to frequency field, and its output is provided for the first input end of differential detection circuit 26 and phase place change correcting circuit 30.
26 pairs in differential detection circuit and carry out differential detection between code element from the corresponding signal of each subcarrier that fft circuit 25 is exported thus, is calculated the phase place change between code element, and this result of calculation is provided for correlation calculations circuit 27 and phase average circuit 29.Correlation calculations circuit 27 is calculated the output of differential detection circuit 26 and the correlation of the configuration information of the subcarrier of transmission CP, and this correlation is offered broadband carrier frequency error counting circuit 28.This broadband carrier frequency error counting circuit 28 is calculated the frequency error of subcarrier interval unit from the peak of correlation, and its output is provided for second input of carrier frequency correcting circuit 23.
Phase average circuit 29 in code element will with the phase average of the output of CP corresponding differential detecting circuit 26, come to determine CPE thus, its output is provided for second input of phase place change correcting circuit 30.This phase place change correcting circuit 30 is proofreaied and correct CPE thus to the output that the correcting vector that produces according to the output that offers the phase average circuit 29 of second input multiply by the fft circuit 25 that offers first input end, and its output is provided for detecting circuit 31.Detecting circuit 31 comes each subcarrier is carried out detection according to modulation system, then, restores data-signal by carrying out inverse mapping.
First of the correlation calculations circuit 27 of Fig. 7 presentation graphs 5 constitutes example.In this correlation calculations circuit 27, the output of the differential detection of differential detection circuit 26 is provided for shift register 2701.This shift register 2701 comprises the output with the corresponding a plurality of branches of the configuration of the subcarrier that transmits CP, and these branches' outputs are provided for the input of summation circuit 2702.This summation circuit 2702 calculates the summation of branch's output of shift register 2701, and its operation result is provided for power calculation circuit 2703.This power calculation circuit 2703 is calculated the power output of summation circuit 2702, and its result of calculation is provided for broadband carrier frequency error counting circuit 28 as the output of correlation calculations circuit 27.
According to formation shown in Figure 7, when the subcarrier of CP was transmitted in output in the whole branches output at shift register 2701, peak value was represented in the output of correlation calculations circuit 27.Therefore, in broadband carrier frequency error counting circuit 28, detect the peak value of the output of correlation calculations circuit 27, obtain, thus, can determine the carrier frequency error of subcarrier interval unit apart from predetermined deviation regularly.
Second of correlation calculations circuit 27 in Fig. 8 presentation graphs 5 constitutes example.In Fig. 8, the part identical with Fig. 7 uses identical label to represent, at this, different piece described.
In this correlation calculations circuit 27, the output of the differential detection of differential detection circuit 26 is provided for filter circuit 2704 between code element.Filter circuit 2704 averages the output of differential detection circuit 26 between this code element on the code element direction, and its output is provided for shift register 2701.The later formation of this shift register 2701 and action are identical during with first configuration example shown in Figure 7.
Therefore, by in correlation calculations circuit 27 shown in Figure 7, increasing filter circuit 2704 between code element, suppress the output stream of correlation calculations circuit 27, thereby can alleviate definite mistake of the error in the broadband carrier frequency error counting circuit 28.
Figure 10 is the formation example of the 3rd embodiment of the correlation calculations circuit 27 among Fig. 5.In Figure 10, the part identical with Fig. 7 and Fig. 8 uses identical label to represent, only different piece described at this.
In this correlation calculations circuit 27, the output of differential detection circuit 26 is averaged on the code element direction by filter circuit between code element 2704, then, directly offers power calculation circuit 2703.That is, the power calculation circuit 2703 of this moment calculates the power output of filter circuit 2704 between code element.Its result of calculation is provided for shift register 2705.This shift register 2705 comprises the output with the corresponding a plurality of branches of the configuration of the subcarrier that transmits CP, and these branches' outputs are provided for the input of summation circuit 2706.The summation of branch's output of these summation circuit 2706 arithmetic shift registers 2705, its operation result is provided for broadband carrier frequency error counting circuit 28 as the output of correlation calculations circuit 27.
In Figure 10, shift register 2705 keeps real number signal, and summation circuit 2706 calculates the summation of real number signal, compares with summation circuit 2702 with the shift register 2701 among Fig. 8 with Fig. 7, can reduce its scale.
The formation example of the correlation calculations circuit 27 in Figure 11 presentation graphs 5.In Figure 11, the part identical with Figure 10 uses identical label to represent, and omits its explanation.
In Figure 11, shift register 2709 keeps 2 value signals, and the summation of summation circuit 2710 computings 2 value signals is compared with summation circuit 2702 with the shift register 2701 among Fig. 8 with Fig. 7, can reduce its scale significantly.And,, just can prevent the misinterpretation that the change by the output level of power calculation circuit 2703 causes if control from the threshold value of threshold setting circuit 2708 output by the size of received signal.
The formation example of the phase place change correcting circuit 30 in Figure 12 presentation graphs 5.In this phase place change correcting circuit 30, the output of phase average circuit 29 is provided for adder 301.This adder 301 is with keeping signal the register 302 of a symbol time to constitute accumulator, the output of phase average circuit 29 is added up in each code element, thus, calculate the accumulative total of phase place change between the code element that begins from computing, its result of calculation (output of adder 301) is provided for correcting vector counting circuit (e
-j φ) 303.It is 1 complex vector that this correcting vector counting circuit 303 is calculated amplitude to-1 times of the output of adder 301 as the phase angle, and its operation result is provided for multiplier 304.This multiplier 304 is the output multiplication of the output of correcting vector counting circuit 303 and fft circuit 25.By this computing, can proofread and correct CPE.
By above formation, according to present embodiment, the configuration information of the subcarrier of the CP that comprises from transmit each code element is calculated the carrier frequency error of subcarrier interval unit, therefore, compares with existing example, can shorten the time of Frequency Synchronization.
Because use CP calculates the phase place change between code element and proofreaies and correct in each code element, just can remove the influence by the caused CPE such as phase noise of tuner 21.Second embodiment
Figure 13 is the block diagram of the formation of the ofdm signal demodulating equipment in the expression second embodiment of the present invention.And in Figure 13, the part identical with Fig. 5 uses identical label to represent.In the figure, the arrow of thick line is represented complex signal, and the arrow of fine rule is represented real number signal, has omitted general control signal such as needed clock in the action of each component parts for the purpose of simplifying the description.
Ofdm signal demodulating equipment shown in Figure 13 replaces the carrier frequency correcting circuit 23 among Fig. 5, replaces at tuner 32 lieutenant colonel's positive carrier frequency errors.This tuner 32 is controlled local frequency with the subcarrier interval that offers the 3rd input with interior narrow-band carrier frequency error signal according to the broadband carrier frequency error signal of the subcarrier interval unit that offers second input, is the ofdm signal that offers first input end the IF frequency band from the RF frequency band transformation, and its output is provided for orthogonal demodulation circuit 22.Other formation is identical with Fig. 5 with action and omit its explanation.The 3rd embodiment
Figure 14 is the block diagram of the formation of the ofdm signal demodulating equipment in the expression third embodiment of the present invention.And in Figure 14, the part identical with Fig. 5 uses identical label to represent.In the figure, the arrow of thick line is represented complex signal, and the arrow of fine rule is represented real number signal, has omitted general control signal such as needed clock in the action of each component parts for the purpose of simplifying the description.
Ofdm signal demodulating equipment shown in Figure 14 replaces the carrier frequency correcting circuit 23 among Fig. 5, replaces at orthogonal demodulation circuit 33 lieutenant colonel's positive carrier frequency errors.This orthogonal demodulation circuit 33 is controlled local frequency with the subcarrier interval that offers the 3rd input with interior narrow-band carrier frequency error signal according to the broadband carrier frequency error signal of the subcarrier interval unit that offers second input, the ofdm signal of the IF frequency band that offers first input end is demodulated into the ofdm signal of base band, and this demodulation output is provided for narrow-band carrier frequency error counting circuit 24 and fft circuit 25.Other formation is identical with Fig. 5 with action and omit its explanation.The 4th embodiment
Figure 15 is the block diagram of the formation of the ofdm signal demodulating equipment in the expression fourth embodiment of the present invention.And in Figure 15, the part identical with Fig. 5 uses identical label to represent.In the figure, the arrow of thick line is represented complex signal, and the arrow of fine rule is represented real number signal, has omitted general control signal such as needed clock in the action of each component parts for the purpose of simplifying the description.
Ofdm signal demodulating equipment shown in Figure 15 be at carrier frequency (fc) correcting circuit 34 lieutenant colonel's positive carrier frequency intervals with interior narrow-band carrier frequency error, the broadband carrier frequency error of corrected sub carrier spacing unit in shift circuit 35.Carrier frequency correcting circuit 34 is proofreaied and correct carrier wave according to the broadband carrier frequency error signal that offers the subcarrier interval unit of second input, this correction carrier wave be multiply by the baseband OFDM signal that offers first input end, proofread and correct carrier frequency error thus, its output is provided for narrow-band carrier frequency error counting circuit 24 and fft circuit 25.Shift circuit 35 according to the broadband carrier frequency error signal of the subcarrier interval unit that offers second input the output of fft circuit 25 at the frequency direction superior displacement, its output is provided for the first input end of differential detection circuit 26 and phase place change correcting circuit.Other formation is identical with Fig. 5 with action and omit its explanation.
Wherein, the carrier frequency error of subcarrier interval unit is the carrier frequency that becomes number of cycles on the effective code element time span; but owing in ofdm signal, exist guard period, the skew of the subcarrier unit in frequency field to depend on the phase place rotation of each code element of guard period length.Therefore, as the formation of Figure 15, when proofreading and correct the broadband carrier frequency error, need to proofread and correct the device of this phase place rotation by the displacement in the frequency field.But, since this phase place to be rotated in whole subcarriers be common, then, in phase place change correcting circuit 30, automatically proofread and correct resembling under the situation that comprises the circuit that is used to remove CPE Figure 15.The 5th embodiment
Figure 16 is the block diagram of the formation of the ofdm signal demodulating equipment in the expression fifth embodiment of the present invention.And in Figure 16, the part identical with Fig. 5 uses identical label to represent.In the figure, the arrow of thick line is represented complex signal, and the arrow of fine rule is represented real number signal, has omitted general control signal such as needed clock in the action of each component parts for the purpose of simplifying the description.
Ofdm signal demodulating equipment shown in Figure 16 replaces the carrier frequency correcting circuit 23 among Fig. 5, is to proofread and correct CPE in detecting circuit 36.This detecting circuit 36 produces correcting vector according to the output that offers the phase average circuit 29 of second input, and this correcting vector be multiply by and the corresponding detection vector of the modulation system of each subcarrier.Then, use this detection vector to come detection is carried out in the output of fft circuit 25, simultaneously, proofread and correct CPE, then, the restored data signal by carrying out inverse mapping.Other formation is identical with Fig. 5 with action and omit its explanation.
Figure 17 represent among Figure 16 detecting circuit 36 be the corresponding formation example of the modulation system of prerequisite with the synchronous detection that uses the SP signal.In this detecting circuit 36, the output of fft circuit 25 is provided for the first input end of complex divider 3604 and the first input end of complex divider 3608.Pilot tone generation circuit 3603 synchronously produces SP with the output of fft circuit 25, and its output is provided for second input of complex divider 3604.These complex divider 3604 usefulness offer the SP that is comprised in the output of regular SP and the fft circuit 25 that offers first input end of pilot tone generation circuit 3603 output of second input is divided by, and thus, calculates the transmission line property that acts on SP.Select the output of its output or memory 3606 to offer the first input end of complex multiplier 3602 by switch (SW) 3605.
On the other hand, the output of phase average circuit 29 is provided for correcting vector counting circuit (e
J φ) 3601.It is 1 complex vector that this correcting vector counting circuit 3601 is calculated amplitude to the output of phase average circuit 29 as the phase angle, and its result of calculation is provided for second input of complex multiplier 3602.Switch 3605 is (if subcarrier of attention when the output of complex divider 3604 is corresponding with SP, then be 1 code element in 4 code elements), select the output of complex divider 3604, (3 code elements in 4 identical code elements) in other cases, the output of selection memory 3606 and exporting.
The transmission line property (proofreading and correct CPE's) that is used for whole subcarriers is obtained in the output of filter circuit 3607 interpolation complex multiplier 3602 on frequency (subcarrier) direction.Its output is provided for second input of complex divider 3608.The output that these complex divider 3608 usefulness offer the filter circuit 3607 of second input is divided by with the output that offers the fft circuit 25 of first input end, thus, synchronous detection is carried out in the output of fft circuit 25..Its output is provided for inverse mapping circuit 3609.This inverse mapping circuit 3609 comes inverse mapping is carried out in the output of complex divider 3608 according to modulation system, thus, restores data-signal.
Figure 18 represents the corresponding formation example of the modulation system with the differential detection being prerequisite of the detecting circuit 36 among Figure 16.In this detecting circuit 36, the output of fft circuit 25 is provided for the first input end of a symbol time delay circuit 3610 and complex divider 3611.A symbol time delay circuit 3610 is symbol time of the output delay of fft circuit 25, and its output is provided for the first input end of complex multiplier 3602.On the other hand, the output of phase average circuit 29 is provided for correcting vector counting circuit (e
J φ) 3601.
It is 1 complex vector that this correcting vector counting circuit 3601 is calculated amplitude to the output of phase average circuit 29 as the phase angle, and its result of calculation is provided for second input of complex multiplier 3602.This complex multiplier 3602 is the output of a symbol time delay circuit 3610 that offers first input end and the output multiplication that offers the correcting vector counting circuit 3601 of second input, thus, signal before the symbol time is carried out the correction of CPE, and its operation result is provided for second input of complex divider 3611.
The output that these complex divider 3611 usefulness offer the complex multiplier 3602 of second input is divided by with the output that offers the fft circuit 25 of first input end, thus, differential detection is carried out in output to fft circuit 25, and its output is provided for inverse mapping circuit 3612.This inverse mapping circuit 3612 comes inverse mapping is carried out in the output of complex divider 3611 according to modulation system, restores data-signal thus.
By above formation, according to present embodiment, the part of the phase place change correcting circuit 30 in can shared first embodiment and the processing of detecting circuit 31, and can cut down circuit scale.The 6th embodiment
Figure 19 is the block diagram of the formation of the ofdm signal demodulating equipment in the expression sixth embodiment of the present invention.And in Figure 19, the part identical with Fig. 5 uses identical label to represent.In the figure, the arrow of thick line is represented complex signal, and the arrow of fine rule is represented real number signal, has omitted general control signal such as needed clock in the action of each component parts for the purpose of simplifying the description.
The correlation calculations circuit 27 in ofdm signal demodulating equipment usefulness correlation calculations 37 while of the circuit execution graph 5 shown in Figure 19 and the processing of phase average circuit 29.
Figure 20 is the formation example of the correlation calculations circuit 37 among Figure 19, and the output of differential detection circuit 26 is provided for shift register 371.This shift register 371 comprises the output with the corresponding a plurality of branches of the configuration of the subcarrier that transmits CP, and these branches' outputs are provided for the input of summation circuit 372.This summation circuit 372 calculates the summation of branch's output of shift register 371, and its operation result is provided for power calculation circuit 373 and phase calculation circuit (tan
-1) 374.
This power calculation circuit 373 is calculated the power output of summation circuit 372, and its result of calculation is provided for broadband carrier frequency error counting circuit 28 as the output of correlation calculations circuit 37.On the other hand, phase calculation circuit 374 is calculated the output phase of summation circuit 372, and its result of calculation is provided for second input of phase place change correcting circuit 30 as second output of correlation calculations circuit 37.
Wherein, when carrier frequency synchronization, the subcarrier of output transmission CP in the output of the branch of shift register 371, therefore, summation circuit 372 is output as: be used to transmit average in code element of change between the code element of subcarrier of CP.
By above formation, according to present embodiment, the part of the correlation calculations circuit 27 in can shared first embodiment and the processing of phase average circuit 29, and can cut down circuit scale.The 7th embodiment
Figure 21 is the block diagram of the formation of the ofdm signal demodulating equipment in the expression seventh embodiment of the present invention.And in Figure 21, the part identical with Fig. 5 uses identical label to represent.In the figure, the arrow of thick line is represented complex signal, and the arrow of fine rule is represented real number signal, has omitted general control signal such as needed clock in the action of each component parts for the purpose of simplifying the description.
Ofdm signal demodulating equipment shown in Figure 21 uses TPS to carry out carrier frequency synchronization and CPE removes, and contrasts with first embodiment, increases and doubly takes advantage of circuit 38 and coefficient device 39.
Wherein, doubly the taking advantage of of the corresponding complex vector of doubly taking advantage of circuit 38 to calculate to calculate of each subcarrier with differential detection circuit 26, its operation result is provided for correlation calculations circuit 27 and phase average circuit 29.This times multiplication has been eliminated the uncertainty of modulating 180 degree of caused phase place change by the differential 2 phase PSK that TPS carried out between code element.
Generally, under the situation of TPS being carried out m phase PSK modulation (m is a natural number), the m that doubly takes advantage of circuit 38 to calculate the corresponding complex vector of exporting with differential detection circuit 26 of each subcarrier doubly takes advantage of, and coefficient device 39 takes advantage of the output of phase average circuit 29 1/m doubly.
By above formation, in the present embodiment, using TPS to calculate the carrier frequency error and the change of the phase place between code element of subcarrier interval unit on the basis of CP and proofreading and correct, therefore, compare with first embodiment, can reduce by the caused error of The noise.The 8th embodiment
Figure 22 is the block diagram of the formation of the ofdm signal demodulating equipment in the expression eighth embodiment of the present invention.And in Figure 22, the part identical with Fig. 5 uses identical label to represent.In the figure, the arrow of thick line is represented complex signal, and the arrow of fine rule is represented real number signal, has omitted general control signal such as needed clock in the action of each component parts for the purpose of simplifying the description.
Ofdm signal demodulating equipment shown in Figure 22 uses TPS to carry out carrier frequency synchronization and CPE removes, and contrasts with first embodiment, increases and doubly takes advantage of circuit 38 and vector rotation circuit 40.
Wherein, doubly take advantage of circuit 38 to calculate and doubly the taking advantage of of the corresponding complex vector of each subcarrier of differential detection circuit 26 output, its operation result is provided for correlation calculations circuit 27 and phase average circuit 29.This times multiplication has been eliminated by TPS and has been carried out the uncertainty that the differential 2 phase PSK between code element modulate 180 degree of caused phase place change.Correlation calculations circuit 27 is calculated the correlation of at least one side's configuration information in output and the subcarrier that transmits CP of doubly taking advantage of circuit 38 and the subcarrier that transmits TPS, and this correlation is provided for broadband carrier frequency error counting circuit 28.
On the other hand, vector rotation circuit 40 judges whether the output of differential detection circuit 26 is included in any zone in the complex number plane zone of being cut apart by the imaginary axis, come the phase place of the complex vector of differential detection circuit 26 outputs is rotated π according to this result of determination, postrotational phase place is included in the identical zone all the time, thus, eliminated the uncertainty of modulating 180 degree of caused phase place change by the differential 2 phase PSK that TPS carried out between code element, its output is provided for phase average circuit 29.Phase average circuit 29 in code element with CP and TPS in the output phase of the corresponding vector rotation circuit 40 of at least one side average, come to determine CPE thus, its output is provided for second input that phase place changes correcting circuit 30.
Generally, under the situation of TPS being carried out m phase PSK modulation (m is a natural number), whether the output of vector rotation circuit 40 judgement differential detection circuit 26 is included in by phase place and is divided in any zone in the individual complex number plane zone of m, come the output complex vector of differential detection circuit 26 is rotated the integral multiple of 2 π/m according to this result of determination, thus, postrotational phase place is included in the identical zone all the time
By above formation, in the present embodiment, identical with the 7th embodiment, using TPS to calculate the carrier frequency error and the change of the phase place between code element of subcarrier interval unit on the basis of CP and proofreading and correct, therefore, compare with first embodiment, can reduce by the caused error of The noise.
And in an embodiment of the present invention, the power calculation of correlation calculations circuit 27 and correlation calculations circuit 37 inside can be calculated the size of the signals such as amplitude sum of amplitude, real part and imaginary part.
In an embodiment of the present invention, phase average circuit 29 in code element with CP and TPS in the output complex vector of at least one side's corresponding differential detecting circuit 26 or vector rotation circuit 40 average, calculate its phase place, thus, the approximate CPE that draws.
In an embodiment of the present invention; broadband carrier frequency error counting circuit 28 is judged the synchronous regime of carrier frequency according to the output of correlation calculations circuit 27; when being in synchronous regime; stop the output of the carrier frequency error signal of subcarrier interval unit; if in this is judged synchronously, rely on the defencive function relative, just can prevent by caused misoperations of influence such as noise and decay with the front and back.
In the above description, 2k mode with the DVB-T standard is that example is illustrated, but, in first to the 8th embodiment, it can be transmission is modulated at the set of the subcarrier that is disposed in each code element same frequency with the identical phase place of each code element the such transmission means of signal, in the 7th to the 8th embodiment, can be m phase PSK modulation (m is a natural number) is carried out in transmission to the sets of subcarriers that is disposed in each code element same frequency the such transmission means of signal.
As described above, ofdm signal demodulating equipment of the present invention uses the pilot signal that is disposed in each code element same frequency to calculate the frequency error of subcarrier interval unit, thus, compares with existing example, can shorten the time of Frequency Synchronization.
Change and proofread and correct by using the pilot signal in each code element same frequency, disposed to calculate phase place between code element, just can eliminate influence by the caused CPE such as phase noise of tuner.
According to the present invention, by a kind of ofdm signal demodulating equipment, can further shorten the time of Frequency Synchronization, and remove influence by the caused CPE such as phase noise of tuner.
Claims (22)
1. the device of a demodulation orthogonal frequency-division multiplex singal, this orthogonal frequency-division multiplex singal is included in first pilot signal that is disposed in the frequency identical with each code element, it is characterized in that, comprising:
Fourier transform device by above-mentioned orthogonal frequency-division multiplex singal is carried out Fourier transform, and is transformed to the frequency axis signal;
The differential detection device carries out differential detection between code element by the output to above-mentioned Fourier transform device, calculates the change between code element;
The correlation calculations device is calculated the correlation of the output of the configuration information of above-mentioned first pilot signal and above-mentioned differential detection device;
Broadband carrier frequency error calculation element, the peak of the output by detecting above-mentioned correlation calculations device is determined the carrier frequency error of subcarrier interval unit;
Broadband carrier frequency means for correcting is proofreaied and correct carrier frequency according to the output of above-mentioned broadband carrier frequency error calculation element.
2. the device of a demodulation orthogonal frequency-division multiplex singal, this orthogonal frequency-division multiplex singal is included in first pilot signal that is disposed in the frequency identical with each code element, it is characterized in that, comprising:
Fourier transform device by above-mentioned orthogonal frequency-division multiplex singal is carried out Fourier transform, and is transformed to the frequency axis signal;
The differential detection device carries out differential detection between code element by the output to above-mentioned Fourier transform device, calculates the change between code element;
The phase average device averages the output phase with the corresponding above-mentioned differential detection device of above-mentioned first pilot signal in code element, determine phase place change common in whole subcarriers thus;
Phase place change means for correcting from the correcting vector that each code element is calculated in the output of above-mentioned phase average device, according to above-mentioned correcting vector, is proofreaied and correct phase place change common in whole subcarriers.
3. the device of a demodulation orthogonal frequency-division multiplex singal, this orthogonal frequency-division multiplex singal is included in first pilot signal that is disposed in the frequency identical with each code element, it is characterized in that, comprising:
Fourier transform device by above-mentioned orthogonal frequency-division multiplex singal is carried out Fourier transform, and is transformed to the frequency axis signal;
The differential detection device carries out differential detection between code element by the output to above-mentioned Fourier transform device, calculates the change between code element;
The correlation calculations device is calculated the correlation of the output of the configuration information of above-mentioned first pilot signal and above-mentioned differential detection device;
Broadband carrier frequency error calculation element, the peak of the output by detecting above-mentioned correlation calculations device is determined the carrier frequency error of subcarrier interval unit;
Broadband carrier frequency means for correcting is proofreaied and correct carrier frequency according to the output of above-mentioned broadband carrier frequency error calculation element;
The phase average device averages the output phase with the corresponding above-mentioned differential detection device of above-mentioned first pilot signal in code element, determine phase place change common in whole subcarriers thus;
Phase place change means for correcting from the correcting vector that each code element is calculated in the output of above-mentioned phase average device, according to above-mentioned correcting vector, is proofreaied and correct phase place change common in whole subcarriers.
4. according to claim 1,3 each described orthogonal frequency division complex signal demodulators, it is characterized in that above-mentioned correlation calculations device is calculated configuration information that 2 value signals by above-mentioned first pilot signal are produced and size from the correlation of the complex vector signal of above-mentioned differential detection device output.
5. according to claim 1,3 each described orthogonal frequency division complex signal demodulators, it is characterized in that above-mentioned correlation calculations device is calculated the size of configuration information that 2 value signals by above-mentioned first pilot signal are produced and the correlation of the complex signal that the output of above-mentioned differential detection device is averaged on the code element direction.
6. according to claim 1,3 each described orthogonal frequency division complex signal demodulators, it is characterized in that above-mentioned correlation calculations device is calculated the correlation of configuration information that 2 value signals by above-mentioned first pilot signal are produced and the size of the real number signal that the output of above-mentioned differential detection device is averaged on the code element direction.
7. according to claim 1,3 each described orthogonal frequency division complex signal demodulators, it is characterized in that the configuration information that 2 value signals produced that above-mentioned correlation calculations device is calculated by above-mentioned first pilot signal carries out the correlation that size is relatively carried out the signal of 2 values with the size of the signal that the output of above-mentioned differential detection device is averaged with predetermined threshold on the code element direction.
8. orthogonal frequency division complex signal demodulator according to claim 7 is characterized in that, above-mentioned correlation calculations device is controlled above-mentioned threshold value by the size of received signal.
9. according to claim 1,3 each described orthogonal frequency division complex signal demodulators, it is characterized in that above-mentioned broadband carrier frequency means for correcting is controlled the local frequency of the tuner of the frequency band transformation that carries out the orthogonal frequency-division multiplex singal imported from transmission line according to the output of above-mentioned broadband carrier frequency error calculation element.
10. according to claim 1,3 each described orthogonal frequency division complex signal demodulators, it is characterized in that above-mentioned broadband carrier frequency means for correcting is controlled the local frequency of the base band OFDM being carried out the orthogonal demodulation device of quadrature demodulation according to the output of above-mentioned broadband carrier frequency error calculation element.
11. according to claim 1,3 each described orthogonal frequency division complex signal demodulators, it is characterized in that, above-mentioned broadband carrier frequency means for correcting generates the correction carrier wave according to the output of above-mentioned broadband carrier frequency error calculation element, this correction carrier wave be multiply by the input signal of above-mentioned Fourier transform device.
12. orthogonal frequency division complex signal demodulator according to claim 1; it is characterized in that; above-mentioned broadband carrier frequency means for correcting is according to the output of above-mentioned broadband carrier frequency error calculation element; the output signal of above-mentioned Fourier transform device is moved on frequency direction; simultaneously, the phase place of proofreading and correct between the code element that depends on guard period length and take place changes.
13. orthogonal frequency division complex signal demodulator according to claim 3, it is characterized in that above-mentioned broadband carrier frequency means for correcting moves the output signal of above-mentioned Fourier transform device according to the output of above-mentioned broadband carrier frequency error calculation element on frequency direction.
14. according to claim 2,3 each described orthogonal frequency division complex signal demodulators, it is characterized in that, above-mentioned phase place change means for correcting is loaded into detector arrangement, this detector arrangement comes detection is carried out in the output of above-mentioned Fourier transform device according to the modulation system of each subcarrier, in this detection, proofread and correct phase place change common in whole subcarriers according to the output of above-mentioned correcting vector calculation element.
15. orthogonal frequency division complex signal demodulator according to claim 14, the demodulation orthogonal frequency division multiplexing signal, this orthogonal frequency division multiplexing signal is on the basis of above-mentioned first pilot signal, be transmitted in the subcarrier symbol zone and disperse and second pilot signal of cycle configuration, it is characterized in that
Above-mentioned detector arrangement is proofreaied and correct phase place change common in whole subcarriers according to the output of above-mentioned correcting vector calculation element, simultaneously, uses above-mentioned second pilot signal to come each subcarrier of synchronous detection.
16. orthogonal frequency division complex signal demodulator according to claim 14, the demodulation orthogonal frequency division multiplexing signal, this orthogonal frequency division multiplexing signal is that the differential modulation that data-signal carries out between code element is transmitted, it is characterized in that, above-mentioned detector arrangement is proofreaied and correct phase place change common in whole subcarriers according to the output of above-mentioned correcting vector calculation element, simultaneously, each subcarrier is carried out differential detection between code element.
17. according to claim 2,3 each described orthogonal frequency division complex signal demodulators, it is characterized in that, above-mentioned phase average device handle averages in code element with the complex vector of the corresponding above-mentioned differential detection device output of above-mentioned first pilot signal, calculate its phase place, determine phase place change common in whole subcarriers thus.
18. orthogonal frequency division complex signal demodulator according to claim 3, it is characterized in that, above-mentioned correlation calculations device comprises above-mentioned phase average device, calculate relevant by 2 the value signals configuration information that is produced and the complex vector signal of being exported from above-mentioned differential detection device of above-mentioned first pilot signal, offer above-mentioned broadband carrier frequency error calculation element, simultaneously, from determining common phase place change whole subcarriers by the phase angle of the resulting vector of above-mentioned related operation, and offer above-mentioned phase place change means for correcting.
19. according to each described orthogonal frequency division complex signal demodulator of claim 1 to 18, it is characterized in that above-mentioned first pilot signal comprises with the identical phase place of each code element modulates the signal that is configured in the sets of subcarriers in the identical frequency of each code element.
20. according to claim 1,3 to 13,18 each described orthogonal frequency division complex signal demodulators, it is characterized in that, when above-mentioned first pilot signal comprises being configured in sets of subcarriers in the identical frequency of each code element when carrying out the signal of m phase PSK modulation (m is a natural number), further comprise a times quadrupler, m is carried out in the output of above-mentioned differential detection device doubly take advantage of, offer above-mentioned correlation calculations device.
21. according to claim 2,3,14 to 18 each described orthogonal frequency division complex signal demodulators, it is characterized in that, when above-mentioned first pilot signal comprises being configured in sets of subcarriers in the identical frequency of each code element when carrying out the signal of m phase PSK modulation (m is a natural number), further comprise:
Times quadrupler carries out m to the output of above-mentioned differential detection device and doubly takes advantage of, and offers above-mentioned phase average device;
Coefficient unit multiply by 1/m to the output of above-mentioned phase average device doubly.
22. according to claim 2,3,14 to 18 each described orthogonal frequency division complex signal demodulators, it is characterized in that, when above-mentioned first pilot signal comprises being configured in sets of subcarriers in the identical frequency of each code element when carrying out the signal of m phase PSK modulation (m is a natural number), further comprise the vector whirligig, whether the output of judging above-mentioned differential detection device is included in by phase place is divided in any zone in complex number plane zone of m, come the complex vector of above-mentioned differential detection device output is rotated the integral multiple of 2 π/m according to this result of determination, thus, postrotational phase place is included in the identical zone all the time, then, offer above-mentioned phase average device.
Applications Claiming Priority (7)
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| JP206639/1997 | 1997-07-31 | ||
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| JP21344997 | 1997-08-07 | ||
| JP01989298A JP3238120B2 (en) | 1997-01-31 | 1998-01-30 | Orthogonal frequency division multiplex signal demodulator |
| JP19892/1998 | 1998-01-30 |
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| CNB2003101195776A Division CN100449972C (en) | 1997-07-31 | 1998-07-30 | Orthogonal frequency division complex signal demodulator |
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| CN1236513A true CN1236513A (en) | 1999-11-24 |
| CN1135763C CN1135763C (en) | 2004-01-21 |
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| CNB988010895A Expired - Lifetime CN1135763C (en) | 1997-07-31 | 1998-07-30 | Quadrature frequency division multiplexing remodulator |
| CNB2003101195776A Expired - Lifetime CN100449972C (en) | 1997-07-31 | 1998-07-30 | Orthogonal frequency division complex signal demodulator |
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| Application Number | Title | Priority Date | Filing Date |
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| CNB2003101195776A Expired - Lifetime CN100449972C (en) | 1997-07-31 | 1998-07-30 | Orthogonal frequency division complex signal demodulator |
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| KR (1) | KR100341200B1 (en) |
| CN (2) | CN1135763C (en) |
| WO (1) | WO1999007095A1 (en) |
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| WO2008151468A1 (en) * | 2007-06-15 | 2008-12-18 | Thomson Licensing | Digital signal receiver and method for receiving digital signal |
| US7480337B2 (en) | 2004-03-23 | 2009-01-20 | Infineon Technologies Ag | Tracking system comprised in an OFDM receiver |
| CN101023611B (en) * | 2004-09-18 | 2010-12-01 | 三星电子株式会社 | Apparatus and method for frequency synchronization in OFDM system |
| CN103685122A (en) * | 2012-08-28 | 2014-03-26 | 三菱电机株式会社 | Frequency error detection device, frequency error detection method, and receiving device |
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Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100738350B1 (en) * | 2004-12-21 | 2007-07-12 | 한국전자통신연구원 | Apparatus and Method of Equalization for Phase Noise Compensation in the Orthogonal Frequency Division Multiplexing communication system |
| JP2006352746A (en) * | 2005-06-20 | 2006-12-28 | Fujitsu Ltd | Receiver for orthogonal frequency division multiplexing transmission |
| CN101471726B (en) * | 2007-12-29 | 2012-10-24 | 京信通信系统（中国）有限公司 | Digitalized automatic frequency correction method based on true frequency reference signal |
| CN101478524B (en) * | 2009-01-22 | 2011-06-15 | 清华大学 | Correction method for phase noise of multi-antenna OFDM system receiving terminal |
| JP2012205122A (en) * | 2011-03-25 | 2012-10-22 | Toshiba Corp | Frequency error detection device |
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Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2904986B2 (en) * | 1992-01-31 | 1999-06-14 | 日本放送協会 | Orthogonal frequency division multiplex digital signal transmitter and receiver |
| JPH0795174A (en) * | 1993-09-27 | 1995-04-07 | Toshiba Corp | Ofdm signal demodulator |
| JP3116764B2 (en) * | 1995-02-15 | 2000-12-11 | 株式会社日立製作所 | Digital transmission signal receiver and digital transmission system |
| JP3555265B2 (en) * | 1995-07-21 | 2004-08-18 | 日本ビクター株式会社 | Frequency division multiplex signal transmitter |
| JPH09153882A (en) * | 1995-09-25 | 1997-06-10 | Victor Co Of Japan Ltd | Orthogonal frequency division multiple signal transmission system, transmitting device and receiving device |
-
1998
- 1998-07-30 CN CNB988010895A patent/CN1135763C/en not_active Expired - Lifetime
- 1998-07-30 KR KR1019997002729A patent/KR100341200B1/en not_active IP Right Cessation
- 1998-07-30 WO PCT/JP1998/003391 patent/WO1999007095A1/en active IP Right Grant
- 1998-07-30 CN CNB2003101195776A patent/CN100449972C/en not_active Expired - Lifetime
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7480337B2 (en) | 2004-03-23 | 2009-01-20 | Infineon Technologies Ag | Tracking system comprised in an OFDM receiver |
| CN1674573B (en) * | 2004-03-23 | 2011-04-06 | 因芬尼昂技术股份公司 | Tracking system comprised in an OFDM receiver |
| CN101023611B (en) * | 2004-09-18 | 2010-12-01 | 三星电子株式会社 | Apparatus and method for frequency synchronization in OFDM system |
| WO2008151468A1 (en) * | 2007-06-15 | 2008-12-18 | Thomson Licensing | Digital signal receiver and method for receiving digital signal |
| CN106982032A (en) * | 2012-05-25 | 2017-07-25 | 高通股份有限公司 | The low-noise amplifier with the signal branch based on transformer for carrier aggregation |
| CN106982032B (en) * | 2012-05-25 | 2021-06-25 | 高通股份有限公司 | Low noise amplifier with transformer based signal splitting for carrier aggregation |
| CN103685122A (en) * | 2012-08-28 | 2014-03-26 | 三菱电机株式会社 | Frequency error detection device, frequency error detection method, and receiving device |
| CN103685122B (en) * | 2012-08-28 | 2016-12-28 | 三菱电机株式会社 | Frequency error detection device, frequency error detecting method and reception device |
| CN113132039A (en) * | 2021-06-16 | 2021-07-16 | 成都德芯数字科技股份有限公司 | RDS and FM pilot signal carrier and phase synchronization method |
Also Published As
| Publication number | Publication date |
|---|---|
| CN1135763C (en) | 2004-01-21 |
| WO1999007095A1 (en) | 1999-02-11 |
| CN1520073A (en) | 2004-08-11 |
| KR100341200B1 (en) | 2002-06-20 |
| CN100449972C (en) | 2009-01-07 |
| KR20000068674A (en) | 2000-11-25 |
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