CN101447958B - Measurement method for performance of modulator and device thereof - Google Patents
Measurement method for performance of modulator and device thereof Download PDFInfo
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- CN101447958B CN101447958B CN2008102473413A CN200810247341A CN101447958B CN 101447958 B CN101447958 B CN 101447958B CN 2008102473413 A CN2008102473413 A CN 2008102473413A CN 200810247341 A CN200810247341 A CN 200810247341A CN 101447958 B CN101447958 B CN 101447958B
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Abstract
The invention discloses a measurement method for the performance of a modulator. The method comprises the following steps: the output signals of a modulator are collected; the output signals are preprocessed, to achieve signals to be measured; the signals to be measured are iterated, to realize the estimation and correction to synchronous parameters, and the synchronous parameters to be measured are output; iterative channel estimation and equalization are performed to the signals to be measured, and measured channel impulse response and signal-to-noise ratio parameters are output. The invention also discloses a measuring device for the performance of a modulator. Iterative synchronization, channel estimation and channel equalization are performed by adopting received 1 to 2 frames of data only, and the short-time performance of the modulator is fully reflected; simultaneously, because the test data is few, the separation of data acquisition equipment and evaluation equipment namely the remote measurement can be realized; on the other hand, the synchronization based on iteration and channel estimation algorithm, the data-aided and directive synchronization and the channel estimation algorithm ensure the accuracy and the precision of the measuring result.
Description
Technical field
The present invention relates to digital information transmission technical field, particularly relate to a kind of method of measurement and device of modulator performance.
Background technology
Fill protection Domain Synchronous block transmission system at interval for training sequence, the problem that the modulator performance measurement scheme is mainly faced is that it(?) how can high accuracy low-cost ground measure and describe intrinsic and the various non-ideal factor sums measuring receiver introducing in the modulator to be measured.This just require measuring receiver to received signal to be measured carry out fast accurate synchronously, channel estimating and channel equalization.
Measuring receiver mainly contains following difference as the part of measuring system with traditional receiver:
(1) purpose difference.The purpose of tradition receiver is to recover originating data, and the purpose of measuring receiver is to be used for assessment, the required precision height.
(2) transmission channel difference.Channel condition between tradition receiver and the transmitter-modulator is abominable, and non-ideal factor is very strong, thereby requires its algorithm to have very strong robustness; Channel condition between measuring receiver and the transmitter-modulator is better, non-ideal factor a little less than, its algorithm needs very high precision.
(3) send the data difference.What the tradition receiver was faced is unknown fully data, and the data that measuring receiver receives according to the demand of accurate measurement, can be filled with given data.
(4) real-time requires different.The exigent real-time of tradition receiver promptly needs it to separate the mediation restore data in real time; Measuring receiver requires lower to real-time, even data acquisition equipment can be separated with assessment apparatus.
Because the actual transmission channel environment is very abominable, the algorithm of traditional receiver need detect continuously usually that the multiframe data are carried out synchronously, channel estimating and channel equalization.Though the result who obtains like this is more accurate, the just long average behavior of modulating system of reflection.In order to reflect the performance of a system all sidedly, then need measuring system can reflect the performance in short-term of modulator exactly.
Summary of the invention
The problem that the embodiment of the invention will solve provides a kind of method of measurement and device of modulator performance, can not accurately reflect the problem of the performance of modulator with measuring system in the solution prior art comprehensively.
For achieving the above object, the technical scheme of the embodiment of the invention provides a kind of method of measurement of modulator performance, said method comprising the steps of: A. gathers the output signal of modulator; B. described output signal is carried out preliminary treatment, obtain measured signal; C. described measured signal is carried out iterative processing, realize the estimation and the correction of synchronization parameter, and the synchronization parameter of output measurement; D. described measured signal is carried out iterative channel and estimate with balanced, and the channel impulse response and the signal to noise ratio parameter of output measurement;
Described step C specifically comprises: C1. utilizes the training sequence achieve frame synchronous; C2. timing frequency deviation, carrier wave frequency deviation and timing skew are carried out rough estimate; C3. carry out carrier wave frequency deviation, timing frequency deviation, regularly skew elimination; C4. estimate timing frequency deviation, carrier wave frequency deviation and timing skew; C5. every estimated result and estimated result are last time added up, the synchronization parameter that finishing iteration and output are measured perhaps returns step C3;
Described step D specifically comprises: D1. utilizes training sequence to do initial channel estimation; D2. eliminate the influence of training sequence, data block is carried out cyclic reconstruction data; D3. the cyclic reconstruction data block is carried out channel equalization and demodulation, recover the transmitting terminal data; D4. utilize cyclic reconstruction data block and transmitting terminal data to carry out channel estimating; D5. iteration finishes and exports channel response and the signal to noise ratio parameter of measuring, or returns step D2.
Wherein, described step B specifically comprises: B1. carries out down-conversion, A/D sampling and front-end processing to described output signal and obtains the zero intermediate frequency baseband signal; B2. described zero intermediate frequency baseband signal is carried out low-pass filtering, filtering noise and interference.
The technical scheme of the embodiment of the invention also provides a kind of measurement mechanism of modulator performance, and described device comprises: signal gathering unit, the output signal that is used to gather modulator; Pretreatment unit is used for described output signal is carried out preliminary treatment, obtains measured signal; Synchronization parameter is estimated and correcting unit, is used for described measured signal is carried out iterative processing, realizes the estimation and the correction of synchronization parameter, and the synchronization parameter of output measurement; The channel estimation and equalization unit is used for that described measured signal is carried out iterative channel and estimates with balanced, and the channel impulse response and the signal to noise ratio parameter of output measurement;
Described synchronization parameter is estimated to comprise with correcting unit: the frame synchronization subelement is used to utilize the training sequence achieve frame synchronous, and timing frequency deviation, carrier wave frequency deviation and timing skew is carried out rough estimate; The synchronous correction subelement is used to carry out carrier wave frequency deviation, timing frequency deviation, regularly skew elimination; Timing frequency deviation estimator unit is used for timing frequency deviation is carefully estimated; The Nonlinear Transformation in Frequency Offset Estimation subelement is used for carrier wave frequency deviation is carefully estimated; Regularly skew estimator unit is used for the timing skew is carefully estimated;
Described channel estimation and equalization unit comprises: the initial channel estimation subelement is used to utilize training sequence to do initial channel estimation; The cyclic reconstruction subelement is used to eliminate the influence of training sequence to data, and data block is carried out cyclic reconstruction; Data are recovered subelement, are used for the cyclic reconstruction data block is carried out channel equalization and demodulation, recover the transmitting terminal data; The channel estimating subelement is used to utilize cyclic reconstruction data block and transmitting terminal data to carry out channel estimating.
Wherein, described pretreatment unit comprises: the zero intermediate frequency baseband signal is obtained subelement, is used for that described output signal is carried out down-conversion, A/D sampling and front-end processing and obtains the zero intermediate frequency baseband signal; The filtering subelement is used for described zero intermediate frequency baseband signal being carried out low-pass filtering, filtering noise and interference.
Compared with prior art, technical scheme of the present invention has following advantage:
The embodiment of the invention only utilize 1 to 2 frame data of reception carry out iteration synchronously, channel estimating and channel equalization, demonstrate fully the performance in short-term of modulator; Simultaneously, because it is less to detect data volume, can realize separating of data acquisition equipment and assessment apparatus, i.e. remote measurement; On the other hand, the synchronous and channel estimation method of assisting and instructing based on the synchronous and channel estimation method and the data of iteration has guaranteed the accuracy and the accuracy of measurement result.
Description of drawings
Fig. 1 is the flow chart of method of measurement of a kind of modulator performance of the embodiment of the invention;
Fig. 2 is that a kind of iteration synchronization parameter of the embodiment of the invention is proofreaied and correct and the flow chart of estimating;
Fig. 3 is that a kind of iterative channel of the embodiment of the invention is estimated and balanced flow chart;
Fig. 4 is the schematic diagram that the instruction row sequence in the embodiment of the invention one influences data;
Fig. 5 is the schematic diagram of the cyclic reconstruction data block in the embodiment of the invention one;
Fig. 6 is the PN595 pattern of the present invention planisphere that obtains according to embodiment one described method of measurement of image data on the spot;
Fig. 7 is a PN420 pattern frame head schematic diagram of the present invention;
Fig. 8 is the PN420 pattern of the present invention planisphere that obtains according to embodiment two described method of measurement of image data on the spot;
Fig. 9 is the structure chart of measurement mechanism of a kind of modulator performance of the embodiment of the invention.
Embodiment
Below in conjunction with drawings and Examples, the specific embodiment of the present invention is described in further detail.Following examples are used to illustrate the present invention, but are not used for limiting the scope of the invention.
The objective of the invention is to propose a kind of modulator method of measurement of filling protection Domain Synchronous block transmission system at interval at training sequence.Because the non-ideal factor that channel, receiver produce all can impact the signal of transmission, so directly do not measure and can not accurately reflect the performance of modulator to receiving data if do not consider non-ideal factor.The non-ideal factor that the present invention mainly considers not match the sending and receiving end sampling clock the inconsistent carrier frequency offset that causes of timing offset problem, transmitter and receiver oscillator frequency that causes and transmitter-modulator and the various filters of receiver bring comprises weak frequency selectivity and equivalent noise.
Carry out modulator for the data of only utilizing 1 to 2 frame and measure, the present invention adopts the synchronous and channel estimating based on iteration.Simultaneously, in order to obtain the measurement result of modulator more accurately, the present invention also adopts the synchronous and channel estimation method that data are auxiliary and instruct.Promptly with known training sequence fill send sequence protection at interval, this training sequence has good autocorrelation performance, can auxiliary measurement system carries out the estimation of frame synchronization and synchronization parameter accurately; Data division also can be filled with known array when channel condition is abominable, and each frame data part all fills identical sequence, can carry out channel estimating accurately by auxiliary measurement system.For the abominable channel of environment, can adopt the multiframe data to carry out time smoothing, improve synchronously and precision of channel estimation.
The method of measurement of a kind of modulator performance of the embodiment of the invention may further comprise the steps as shown in Figure 1:
Step s101, the output signal of gathering modulator.
Step s102 carries out preliminary treatment to output signal, obtains measured signal.At first, described output signal is carried out down-conversion, A/D sampling and front-end processing and obtain the zero intermediate frequency baseband signal; Then, described zero intermediate frequency baseband signal is carried out low-pass filtering, noise and interference that filtering useful signal band is outer.
Step s103 carries out iterative processing to measured signal, realizes the estimation and the correction of synchronization parameter, and the synchronization parameter of output measurement.Because can there be non-ideal factors such as carrier wave frequency deviation, timing frequency deviation in the unsteadiness of devices such as transmitter and receiver crystal oscillator.In order to make The ultimate results accurate, need carry out regularly and the estimation and the correction of carrier synchronization parameter.It mainly comprises the estimation of frame synchronization position, the estimation of the estimation of timing frequency deviation and correction, carrier frequency offset and correction etc.
The present invention realizes the estimation and the correction of synchronization parameter by the iterative processing to signal.The signal x that first iteration is used
0(n) be the measured signal x (n) that obtains through processing of step A, then signal carried out frame synchronization, timing frequency deviation, carrier wave frequency deviation, the regularly rough estimate of skew, and utilize estimated result signal x
0(n) proofread and correct, obtain signal x
1(n), use for next iteration.Since the iteration second time, the signal x that at first utilizes last iteration to obtain
I-1(n) carry out frame synchronization, timing frequency deviation, carrier wave frequency deviation, the regularly thin estimation of skew, and the estimated result of new estimated result and last iteration is added up.Utilize the synchronization parameter estimated result after adding up that primary signal x (n) is carried out the synchronization parameter correction again, obtain the update signal x of this iteration
i(n).Enter next iteration then.
Step s104 carries out iterative channel to measured signal and estimates with balanced, and the channel impulse response and the signal to noise ratio parameter of output measurement.Be subjected to the interior unevenness of band of various filters in transmitting terminal and the test lead and the influence of imperfect transmission, the channel of transmission signals experience has weak frequency selectivity usually, therefore need carry out channel estimating and channel equalization.
In order to eliminate the influence of non-ideal factor accurately, the channel estimating part still adopts iterative idea to carry out, and the iteration object of channel estimating is a channel impulse response.In the i time iterative process, utilize last iteration h as a result
I-1(n) (the h that first iteration uses step 301 to estimate
0(n)), the sequence that obtains after synchronous correction finished is finished and is removed after training sequence influence, the cyclic reconstruction operation, utilizes itself and the relation that sends sequence D (n) circular convolution to carry out channel estimating, obtains channel system function updating value h
i(n), utilize h
i(n) carry out channel equalization, and with in its substitution next iteration process.Iteration can obtain more precise channels equilibrium result after finishing each time.
Wherein, the flow process of correction of iteration synchronization parameter and estimation may further comprise the steps as shown in Figure 2 among the step s103:
Step s201 utilizes the training sequence achieve frame synchronous;
Step s202 carries out rough estimate to timing frequency deviation, carrier wave frequency deviation and timing skew;
Step s203 carries out carrier wave frequency deviation, timing frequency deviation, regularly skew elimination;
Step s204 estimates timing frequency deviation, carrier wave frequency deviation and timing skew;
Step s205 adds up every estimated result and estimated result last time, and the synchronization parameter that finishing iteration and output are measured perhaps returns step s203.
Wherein, the flow process of iterative channel estimation and equilibrium may further comprise the steps as shown in Figure 3 among the step s104:
Step s301 utilizes training sequence to do initial channel estimation;
Step s302 eliminates the influence of training sequence to data, and data block is carried out cyclic reconstruction;
Step s303 carries out channel equalization and demodulation to the cyclic reconstruction data block, recovers the transmitting terminal data;
Step s304 utilizes cyclic reconstruction data block and transmitting terminal data to carry out channel estimating;
Step s305, iteration finishes and output is measured channel response and signal to noise ratio parameter, or return step s302.
Embodiment one
The modulator of present embodiment adopts the PN595 pattern in the China Digital TV terrestrial broadcasting transmission standard (GB20600-2006 is called for short DTMB).Its signal frame length is 4375 symbols, is made up of frame head and frame.The length of header signal is 595 symbols, is that length is preceding 595 chips of 1023 m sequence.Modulating mode adopts single-carrier modulated.
For the system of frame head employing PN595 pattern, at first the signal with the signal acquiring board collection carries out the front end signal processing, eliminates known carrier wave frequency deviation and timing frequency deviation, and carries out filtering.Carry out the frame synchronization found relevant peaks then, utilize relevant peaks to carry out carrier wave frequency deviation, timing frequency deviation, the regularly rough estimate of skew.Utilize the rough estimate parameter that data are carried out after synchronization parameter proofreaies and correct, utilize alternative manner to data carry out carrier wave frequency deviation, timing frequency deviation, regularly skew is carefully estimated and is proofreaied and correct.After finishing synchronously, utilize local PN sequence to carry out channel estimation and equalization, and utilize the method for iteration to obtain channel estimation and equalization accurately.Utilize balanced data to carry out the isoparametric calculating of signal to noise ratio at last.
The concrete implementation step of measuring system that the present invention is directed to said system is as follows:
Steps A 1: data acquisition and front end signal are handled.Comprise and carry out Hilbert filtering, Digital Down Convert, low-pass filtering, the sampling processing that subtracts to received signal successively.Wherein can obtain the quadrature component (imaginary part) of signal by Hilbert filtering, the known carrier wave frequency deviation is eliminated in Digital Down Convert, subtracts sampling and eliminates known timing frequency deviation.
Step B1: the iteration synchronization parameter is proofreaied and correct and is estimated.Describe the synchronous flow process that frame structure adopts the modulator method of measurement of PN595 pattern below in detail.
Step B11: frame synchronization
Receiving sequence and local PN sequence are carried out the difference cross-correlation, and achieve frame is synchronous.Adopting the difference cross-correlation to replace common cross-correlation is frame synchronization in order to guarantee to have big carrier wave frequency deviation; The relevant peaks phase angle of difference cross-correlation comprises carrier wave frequency deviation information simultaneously, can be used for carrying out the rough estimate of carrier wave frequency deviation, utilizes the position of two relevant peaks then can carry out timing frequency deviation, the regularly rough estimate of skew.
Step B12: utilize the estimated result of carrier wave frequency deviation, timing frequency deviation, timing skew, carry out carrier wave frequency deviation, timing frequency deviation, regularly skew elimination.This step, the synchronization parameter that adopts the estimation of last iteration process to obtain was proofreaied and correct (synchronization parameter of the frame synchronization of iteration employing for the first time rough estimate) to data as the initial step of iterative process.
Step B13: timing frequency deviation is carefully estimated.
With length in the frame signal frame is that 3780 data block is taken out and done auto-correlation, utilizes the anisopleual degree in auto-correlation peak to carry out timing frequency deviation and carefully estimates.
Step B14: carrier wave frequency deviation is carefully estimated
Nonlinear Transformation in Frequency Offset Estimation comprises rough estimate and two kinds of methods of thin estimation.Because the thin high scope of estimating of precision of carrier wave frequency deviation is little, so carry out rough estimate earlier in preceding twice iteration, carefully estimates in the iterative process afterwards." rough estimate " precision in this step is higher than the estimated accuracy in the frame synchronization.
The rough estimate utilization is carried out Nonlinear Transformation in Frequency Offset Estimation with signal and the local PN sequence relevant peaks that auto-correlation obtains that is concerned with, and carefully estimates to utilize the autocorrelative relevant peaks of data to carry out Nonlinear Transformation in Frequency Offset Estimation.
Step B15: regularly skew is carefully estimated
Utilizing PN sequence in the receiving sequence and local sequence cross-correlation relevant peaks both sides degree not to be carried out the timing skew carefully estimates.
After this step finishes every estimated result and estimated result are last time added up (if for the first time iteration then with iteration before the rough estimate result add up) return (2) step " utilize carrier wave frequency deviation, timing frequency deviation, the estimated result of skew regularly, carry out carrier wave frequency deviation, timing frequency deviation, regularly skew is eliminated " then and carry out iterative process next time.
Step C1: iterative channel is estimated with balanced.Describe the channel estimation and equalization flow process that frame structure adopts the modulator method of measurement of PN595 pattern below in detail.
Step C11: utilize training sequence to do initial channel estimation.The PN sequence of first frame of receiving sequence is x
c(n), the local PN sequence of its correspondence is c (n).Then
Step C12: eliminate the influence of training sequence, data block is carried out cyclic reconstruction to data.
As Fig. 4, send signal through after the channel, training sequence can cause interference to data block.By estimating the hangover part of training sequence, eliminate the interference of training sequence to data block.If the first frame PN sequence is c
1(n), the second frame PN sequence is c
2(n), last iteration process estimated channel impulse response is designated as h
I-1(n)
S
1(n)＝c
1(n)*h
i-1(n)
S
2(n)＝c
2(n)*h
i-1(n)
Convolution algorithm is a linear convolution in the following formula.From S
1(n), S
2(n) can obtain the influence I of the first frame PN in to the first frame data piece
1(n) and the second frame PN to the I that influences of the first frame data piece
2(n).If the receiving sequence first frame data piece is x (n), then eliminating PN influences the back to data block:
As Fig. 5,, need offset the data block of disturbing except training sequence and carry out cyclic reconstruction in order to obtain launching the circular convolution result of data and channel.If the result of last iterative process symbol demodulation is x
d I-1(n) (iteration is supposed for the first time
)。Note
Then from following formula, can obtain the influence I of current data block to the former frame data
3(n) and back one frame data piece to the I that influences of current data
4(n).The data that can obtain reconstituting circular convolution thus are:
Because the PN595 pattern adopts the PN of stationary phase, thus can adopt the virtual frames technology to carry out channel estimation and equalization, if adopt the virtual frames technology then this step can omit.
Step C13: the cyclic reconstruction data block is carried out channel equalization and demodulation, recover the transmitting terminal data.
If the frequency domain data position X of cyclic reconstruction data block correspondence
i(k), then balanced back result is
Because the data message under this pattern transmits under single carrier mode, therefore balanced data need be reverted back time domain carries out symbol judgement again, obtains transmitting terminal data x
d i(n).
Step C14: utilize cyclic reconstruction data block and transmitting terminal data to carry out channel estimating.
Step C15: iteration finishes and output is measured channel response and signal to noise ratio parameter, or return step C12.
After Figure 6 shows that the data of gathering one group of PN595 pattern on the spot, by PC according to top step carry out that the iteration synchronization parameter is proofreaied and correct, iterative channel is estimated with equilibrium after planisphere, synchronization parameter carrier wave frequency deviation-165910.4Hz wherein, timing frequency deviation-17.54ppm.Calculating the balanced data signal to noise ratio is 31.67dB.
Embodiment two
The signal frame that the modulator of the embodiment of the invention two adopts adopts the PN420 pattern in the China Digital TV terrestrial broadcasting transmission standard (GB20600-2006 is called for short DTMB).Its signal frame length is 4200 symbols, is made up of frame head and frame.Frame head is the PN sequence of 420 symbols, and the PN sequence is made of the m sequence and the cyclic extensions thereof of 255 symbols, the PN sequence of the corresponding out of phase of different cyclic shifts of m sequence.Frame head form such as Fig. 7.Modulating mode adopts the OFDM modulation technique.
Owing to adopt each frame frame head phase place of signal frame of PN420 pattern all different, therefore the signal of handling through front end signal need detect two relevant peaks when frame synchronization, utilize differing of two relevant peaks to obtain the local PN sequence of its correspondence then, so that channel estimating is carried out in the back.After frame synchronization is finished, utilize relevant peaks to carry out carrier wave frequency deviation, timing frequency deviation, the regularly rough estimate of skew.Utilize the rough estimate parameter that data are carried out after synchronization parameter proofreaies and correct, utilize alternative manner to data carry out carrier wave frequency deviation, timing frequency deviation, regularly skew is carefully estimated and is proofreaied and correct.Utilize the PN sequence to carry out the rough estimate and thick equilibrium of channel after finishing synchronously, utilize alternative manner to carry out channel then and carefully estimate and thin equilibrium, utilize balanced data to carry out the isoparametric calculating of signal to noise ratio at last.
The concrete implementation step of measuring system that the present invention is directed to said system is as follows:
Steps A 2: data acquisition and front end signal are handled.Identical with the front end signal processing procedure of embodiment one, carry out Hilbert filtering, Digital Down Convert, low-pass filtering, the sampling processing that subtracts to received signal successively.
Step B2: the iteration synchronization parameter is proofreaied and correct and is estimated.Comprise frame synchronization, carrier synchronization, regularly synchronously.Describe the synchronous flow process that frame structure adopts the modulator method of measurement of PN420 pattern below in detail.
Step B21: frame synchronization.
Similar with the step B11 among the embodiment one, it is relevant that receiving sequence and local PN sequence are carried out difference, and achieve frame is synchronous, and adopting the relevant cross-correlation that replaces of difference is frame synchronization in order to guarantee to have big carrier wave frequency deviation.Because the every frame signal frame head of PN420 pattern phase place difference, so do frame synchronization (local PN one has 255, that in the middle of just getting) with the front cross frame of the data of handling through steps A 1 with preceding 308 symbols of the 113rd PN sequence in the local PN sequence.Utilize differing of two relevant peaks to obtain the phase difference of these two frame data PN sequence, thereby obtain the local PN sequence of its correspondence.
Remaining process and PN595 mode class are seemingly, by described measured signal is carried out iterative processing, realize the estimation and the correction of synchronization parameter, mainly comprise the estimation of frame synchronization position, the estimation of the estimation of timing offset and correction, carrier frequency offset and correction etc., and the synchronization parameter of output measurement
Step C2: iterative channel is estimated with balanced.Describe the channel estimation and equalization flow process that frame structure adopts the modulator method of measurement of PN420 pattern below in detail.
Step C21: utilize training sequence to do initial channel estimation with balanced;
Step C22: eliminate the influence of training sequence, data block is carried out cyclic reconstruction to data;
Step C23: the cyclic reconstruction data block is carried out channel equalization and demodulation, recover the transmitting terminal data;
Step C24: utilize cyclic reconstruction data block and transmitting terminal data to carry out channel estimating;
Step C25: iteration finishes and output is measured channel response and signal to noise ratio parameter, or return step C22.
Because every frame signal frame head phase place difference of PN420 pattern can't adopt the virtual frames technology to carry out channel estimation and equalization, so step C22 cannot omit.The The data OFDM modulation technique of while PN420 pattern, its data message transmits at frequency domain.Therefore when in step C23, carrying out symbol demodulation directly to the sequence S after the equilibrium
1 i(k) carry out promptly obtaining the transmitting terminal data behind the symbol judgement.All the other operations are identical with the PN595 pattern.
After Figure 8 shows that the data of gathering one group of PN420 pattern on the spot, by PC according to top step carry out that the iteration synchronization parameter is proofreaied and correct, iterative channel is estimated with equilibrium after planisphere, synchronization parameter carrier wave frequency deviation-165964.1Hz wherein, timing frequency deviation-15.84ppm.Calculating the balanced data signal to noise ratio is 31.67dB.
The measurement mechanism of a kind of modulator performance of the embodiment of the invention comprises signal gathering unit 91, pretreatment unit 92, synchronization parameter estimation and correcting unit 93 and channel estimation and equalization unit 94 as shown in Figure 9.Wherein, pretreatment unit 92 is estimated to be connected with correcting unit 93 with signal gathering unit 91 and synchronization parameter respectively, and synchronization parameter is estimated to be connected with channel estimation and equalization unit 94 with correcting unit 93.Signal gathering unit 91 is used to gather the output signal of modulator; Pretreatment unit 92 is used for described output signal is carried out preliminary treatment, obtains measured signal; Synchronization parameter is estimated to be used for described measured signal is carried out iterative processing with correcting unit 93, realizes the estimation and the correction of synchronization parameter, and the synchronization parameter of output measurement; Channel estimation and equalization unit 94 is used for that described measured signal is carried out iterative channel to be estimated with balanced, and the channel impulse response and the signal to noise ratio parameter of output measurement.
Synchronization parameter is estimated to comprise frame synchronization subelement 931, synchronous correction subelement 932, timing frequency deviation estimator unit 933, Nonlinear Transformation in Frequency Offset Estimation subelement 934 and timing skew estimator unit 935 with correcting unit 93.Wherein, synchronous correction subelement 932 is connected with frame synchronization subelement 931, timing frequency deviation estimator unit 933 and timing skew estimator unit 935 respectively, and Nonlinear Transformation in Frequency Offset Estimation subelement 934 is connected with timing skew estimator unit 935 with timing frequency deviation estimator unit 933 respectively.Frame synchronization subelement 931 is used to utilize the training sequence achieve frame synchronous, and timing frequency deviation, carrier wave frequency deviation and timing skew are carried out rough estimate; Synchronous correction subelement 932 is used to carry out carrier wave frequency deviation, timing frequency deviation, regularly skew is eliminated; Timing frequency deviation estimator unit 933 is used for timing frequency deviation is carefully estimated; Nonlinear Transformation in Frequency Offset Estimation subelement 934 is used for carrier wave frequency deviation is carefully estimated; Regularly skew estimator unit 935 is used for the timing skew is carefully estimated.
Channel estimation and equalization unit 94 comprises initial channel estimation subelement 941, cyclic reconstruction subelement 942, data recovery subelement 943 and channel estimating subelement 944.Wherein, cyclic reconstruction subelement 942 recovers subelement 943 with initial channel estimation subelement 941, data respectively and is connected with channel estimating subelement 944, and data are recovered subelement 943 and are connected with channel estimating subelement 944.Initial channel estimation subelement 941 is used to utilize training sequence to do initial channel estimation; Cyclic reconstruction subelement 942 is used to eliminate the influence of training sequence to data, and data block is carried out cyclic reconstruction; Data are recovered subelement 943 and are used for the cyclic reconstruction data block is carried out channel equalization and demodulation, recover the transmitting terminal data; Channel estimating subelement 944 is used to utilize cyclic reconstruction data block and transmitting terminal data to carry out channel estimating.
The above only is a preferred implementation of the present invention; should be pointed out that for those skilled in the art, under the prerequisite that does not break away from the technology of the present invention principle; can also make some improvements and modifications, these improvements and modifications also should be considered as protection scope of the present invention.
Claims (4)
1. the method for measurement of a modulator performance is characterized in that, said method comprising the steps of:
A. gather the output signal of modulator;
B. described output signal is carried out preliminary treatment, obtain measured signal;
C. described measured signal is carried out iterative processing, realize the estimation and the correction of synchronization parameter, and the synchronization parameter of output measurement;
D. described measured signal is carried out iterative channel and estimate with balanced, and the channel impulse response and the signal to noise ratio parameter of output measurement;
Described step C specifically comprises:
C1. utilize the training sequence achieve frame synchronous;
C2. timing frequency deviation, carrier wave frequency deviation and timing skew are carried out rough estimate;
C3. carry out carrier wave frequency deviation, timing frequency deviation, regularly skew elimination;
C4. timing frequency deviation, carrier wave frequency deviation and timing skew are carefully estimated;
C5. every estimated result and estimated result are last time added up, the synchronization parameter that finishing iteration and output are measured perhaps returns step C3;
Described step D specifically comprises:
D1. utilize training sequence to do initial channel estimation;
D2. eliminate the influence of training sequence, data block is carried out cyclic reconstruction data;
D3. the cyclic reconstruction data block is carried out channel equalization and demodulation, recover the transmitting terminal data;
D4. utilize cyclic reconstruction data block and transmitting terminal data to carry out channel estimating;
D5. iteration finishes and exports channel response and the signal to noise ratio parameter of measuring, or returns step D2.
2. the method for measurement of modulator performance according to claim 1 is characterized in that described step B specifically comprises:
B1. described output signal is carried out down-conversion, A/D sampling and front-end processing and obtain the zero intermediate frequency baseband signal;
B2. described zero intermediate frequency baseband signal is carried out low-pass filtering, filtering noise and interference.
3. the measurement mechanism of a modulator performance is characterized in that, described device comprises:
Signal gathering unit, the output signal that is used to gather modulator;
Pretreatment unit is used for described output signal is carried out preliminary treatment, obtains measured signal;
Synchronization parameter is estimated and correcting unit, is used for described measured signal is carried out iterative processing, realizes the estimation and the correction of synchronization parameter, and the synchronization parameter of output measurement;
The channel estimation and equalization unit is used for that described measured signal is carried out iterative channel and estimates with balanced, and the channel impulse response and the signal to noise ratio parameter of output measurement;
Described synchronization parameter is estimated to comprise with correcting unit:
The frame synchronization subelement is used to utilize the training sequence achieve frame synchronous, and timing frequency deviation, carrier wave frequency deviation and timing skew are carried out rough estimate;
The synchronous correction subelement is used to carry out carrier wave frequency deviation, timing frequency deviation, regularly skew elimination;
Timing frequency deviation estimator unit is used for timing frequency deviation is carefully estimated;
The Nonlinear Transformation in Frequency Offset Estimation subelement is used for carrier wave frequency deviation is carefully estimated;
Regularly skew estimator unit is used for the timing skew is carefully estimated;
Described channel estimation and equalization unit comprises:
The initial channel estimation subelement is used to utilize training sequence to do initial channel estimation;
The cyclic reconstruction subelement is used to eliminate the influence of training sequence to data, and data block is carried out cyclic reconstruction;
Data are recovered subelement, are used for the cyclic reconstruction data block is carried out channel equalization and demodulation, recover the transmitting terminal data;
The channel estimating subelement is used to utilize cyclic reconstruction data block and transmitting terminal data to carry out channel estimating.
4. as the measurement mechanism of modulator performance as described in the claim 3, it is characterized in that described pretreatment unit comprises:
The zero intermediate frequency baseband signal is obtained subelement, is used for that described output signal is carried out down-conversion, A/D sampling and front-end processing and obtains the zero intermediate frequency baseband signal;
The filtering subelement is used for described zero intermediate frequency baseband signal being carried out low-pass filtering, filtering noise and interference.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2008102473413A CN101447958B (en) | 2008-12-30 | 2008-12-30 | Measurement method for performance of modulator and device thereof |
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|---|---|---|---|
| CN2008102473413A CN101447958B (en) | 2008-12-30 | 2008-12-30 | Measurement method for performance of modulator and device thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
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| CN101447958B true CN101447958B (en) | 2011-05-11 |
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| CN101888364B (en) * | 2010-07-16 | 2013-09-25 | 华为技术有限公司 | Carrier synchronization processing method and device |
| CN103414523B (en) * | 2012-12-14 | 2015-07-22 | 中国计量科学研究院 | Method for measuring modulation quality parameters based on software radio technology and system |
| CN103095614B (en) * | 2013-01-24 | 2015-06-24 | 电子科技大学 | Joint equalization and frequency offset estimation device in proruption coherent optical fiber communications |
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| CN1574822A (en) * | 2003-06-18 | 2005-02-02 | 三星电子株式会社 | Apparatus and method for measuring signal-to-noise ratio in orthogonal frequency division multiplexing system |
| CN1578485A (en) * | 2003-07-28 | 2005-02-09 | 凯明信息科技股份有限公司 | Automatic correcting frequency method for time-division radio communication system and apparatus thereof |
| EP1635592A1 (en) * | 2004-09-13 | 2006-03-15 | Alcatel | Estimation of channel quality for wireless communication network |
| CN1778035A (en) * | 2003-04-24 | 2006-05-24 | 皇家飞利浦电子股份有限公司 | Quadrature modulator and calibration method |
| EP1228611B1 (en) * | 1999-10-29 | 2007-05-30 | Telefonaktiebolaget LM Ericsson (publ) | Radio receiver with two stages of dc offset correction, synchronisation and channel estimation |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| EP1228611B1 (en) * | 1999-10-29 | 2007-05-30 | Telefonaktiebolaget LM Ericsson (publ) | Radio receiver with two stages of dc offset correction, synchronisation and channel estimation |
| CN1778035A (en) * | 2003-04-24 | 2006-05-24 | 皇家飞利浦电子股份有限公司 | Quadrature modulator and calibration method |
| CN1574822A (en) * | 2003-06-18 | 2005-02-02 | 三星电子株式会社 | Apparatus and method for measuring signal-to-noise ratio in orthogonal frequency division multiplexing system |
| CN1578485A (en) * | 2003-07-28 | 2005-02-09 | 凯明信息科技股份有限公司 | Automatic correcting frequency method for time-division radio communication system and apparatus thereof |
| EP1635592A1 (en) * | 2004-09-13 | 2006-03-15 | Alcatel | Estimation of channel quality for wireless communication network |
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