Realize the method that signal modulation mass measurement and planisphere showTechnical field
The present invention relates to less radio-frequency field tests, more particularly to the mass measurement of the modulated signal containing intersymbol interference andDisplay field, specifically refers to a kind of method for realizing that signal modulation mass measurement and planisphere show.
Background technology
In modern digital radio communication, the wireless device of many standards can use formed filter in transmitter, to realityModulated signal carries out molding filtration, then the signal is used for launching.This mode can introduce intersymbol interference to source digital signal（ISI）.For measurand transmitter signal quality, in receiving terminal, common processing method is first by transmitting terminal formed filterMatched filter eliminating intersymbol interference.For example in the wireless communication system of the standards such as TD-SCDMA and WCDMA, transmitting terminalUsing RRC wave filter as formed filter.For measurand transmitter signal quality, need to be filtered using corresponding RRC in receiving terminalThe docking collection of letters number of ripple device carries out matched filtering, and to remove the ISI received in signal, the then docking collection of letters number carries out the modulation such as EVMThe measurement of quality index, and be capable of achieving the planisphere of reaction signal modulation quality and show.
Prior art is suffered from the drawback that：
1st, in current main-stream communication standard, the formed filter used by some standards such as GSM/EDGE（Class gaussian filteringDevice）Without corresponding matched filter, it is impossible to receive modulation quality EVM of signal using such technology accurate measurement；
2nd, in measurement process, needs draw the planisphere of reflection transmitter primary signal modulation quality, using such technologyIt is not easy to the planisphere for reducing on request with showing such signal.
The content of the invention
The purpose of the present invention is the shortcoming for overcoming above-mentioned prior art, there is provided one kind can be realized being sent according to reconstructEnd reference signal is compared with receiving terminal measurement signal and obtains vector modulation error, avoids some communication standard transmitting terminals from not havingThe mode of standby matched filtering and the limitation of traditional measurement mode cannot be suitable for, signal modulation is realized with broader applications scopeThe method that mass measurement and planisphere show.
To achieve these goals, it is of the invention to realize method that signal modulation mass measurement and planisphere show with such asLower composition：
This realizes the method that signal modulation mass measurement and planisphere show, which is mainly characterized by, and described method includesFollowing steps：
（1）Optimum sampling reception signal is extracted in the sampled signal that receiving terminal is received and is divided into two paths of signals graspedMake；
（2）The measurement wave filter that first via optimum sampling reception signal measured agreement specifies is obtained for modulating matterThe reception measurement signal of measurement；
（3）The survey that Jing overmoldings wave filter and measurement agreement specify after signal is re-modulated is received to the second road optimum samplingAmount wave filter obtains the reception reference signal for modulation quality measurement；
（4）Described reception measurement signal and reception reference signal for modulation quality measurement are compared and are obtainedVector modulation error and the planisphere of vector modulation error distribution.
It is preferred that the described optimum sampling that extracts in the sampled signal that receiving terminal is received receives signal, including followingStep：
（11）The sampled signal that receiving terminal is received is synchronized and obtains optimum sampling point；
（12）Optimum sampling is extracted in the sampled signal that receiving terminal is received according to optimum sampling point receives signal.
It is preferred that described obtains the measurement wave filter that first via optimum sampling reception signal measured agreement specifiesFor the reception measurement signal of modulation quality measurement, comprise the following steps：
（21）Receiving signal to first via optimum sampling carries out minimizing error operation process；
（22）To through the measured agreement regulation of first via optimum sampling reception signal for minimum that error operation is processedMeasurement wave filter obtain for modulation quality measurement reception measurement signal.
More preferably, the described signal that receives to first via optimum sampling carries out minimizing error operation process, specially：
Signal is received to first via optimum sampling carries out correcting frequency deviation, initial phase deflection correction, DC compensation, root-mean-square errorCompensation and power normalization operation are processed.
It is preferred that described receives Jing overmoldings wave filter and measurement association after signal is re-modulated to the second road optimum samplingThe measurement wave filter of view regulation obtains the reception reference signal for modulation quality measurement, comprises the following steps：
（31）Second road optimum sampling is received after signal carries out correcting frequency deviation and initial phase deflection correction and parses the second tunnelOptimum sampling receives the symbolic information of signal；
（32）The symbolic information that signal is received according to the second road optimum sampling re-modulates out standard modulated signal；
（33）By the classical modulation signal of re-modulation by obtaining preferable transmitting with transmitting terminal identical formed filterSignal；
（34）Described preferable transmission signal is obtained for modulation quality by the measurement wave filter that measurement agreement specifiesThe reception reference signal of measurement.
More preferably, described step（33）With（34）Between, it is further comprising the steps of：
（331）Obtain reflecting intersymbol interference pair according to described preferable transmission signal and the classical modulation signal for re-modulatingThe planisphere of modulated signal distribution influence rule.
More preferably, it is described by the described reception measurement signal for modulation quality measurement and to receive reference signal and carry outRelatively and vector modulation error is obtained, comprised the following steps：
（41）Described reception measurement signal and reception reference signal for modulation quality measurement is compared and is adjustedError processed；
（42）Vector modulation error is calculated according to described modulation error.
Further, described step（4）Afterwards, it is further comprising the steps of：
（5）The classical modulation signal of described re-modulation and modulation error synthesis are obtained reflecting and affected by modulation errorModulated signal planisphere.
Further, described step（4）Afterwards, it is further comprising the steps of：
（6）The classical modulation signal addition simulaed interference signal of described re-modulation is obtained containing simulation input interferenceModulated signal；
（7）The described modulated signal containing simulation input interference and modulation error synthesis are obtained reflecting and done by simulation inputDisturb the planisphere of the modulated signal of impact.
The method that signal modulation mass measurement and planisphere show of realizing in the invention is employed, with following beneficial effectReally：
Method of the present invention according to reconstruct transmitting terminal reference signal, is compared with receiving terminal measurement signal and show that modulation is missedDifference vector, can be used for the measurement of modulation quality EVM, and can very easily draw the modulated signal of reflection modulation quality situationDeng planisphere；This scheme is avoided, and does not possess the mode of matched filtering in some communication standard transmitting terminals, it is impossible to be suitable for traditionThe limitation of mass measurement is modulated with Filtering Processing scheme；Meanwhile, this scheme can also be using the ginseng obtained in measurement procedureAmount, carries out signal interference simulation test, and can be to the modulated signal under the influence of various error states, using the mode of planisphereTo show measurement result, with wider range of application.
Description of the drawings
Fig. 1 is the flow chart for realizing method that signal modulation mass measurement and planisphere show of the present invention.
Fig. 2 is that the present invention realizes that method that signal modulation mass measurement and planisphere show is applied to the flow process of embodimentFigure.
Specific embodiment
In order to more clearly describe the technology contents of the present invention, carry out with reference to specific embodiment furtherDescription.
The present invention core concept be：The present invention not using the method for matched filter come remove receive signal ISI（Inter Symbol Interference, intersymbol interference）, but by reducing ideal signal of the transmitting terminal comprising ISI, with thisFor reference signal, modulation quality EVM of transmission signal is tested（Error Vector Magnitude, vector modulation error）.In test process, according to universal test standard, signal and reference signal will be received by same measurement wave filter, then to thisTwo kinds of signals are compared, and draw the vector amplitude error of transmitter signal（EVM）.And by EVM and reference signal come also primaryPenetrate machine original modulated signal.
The present invention based on the principle that：
For terminal test system, when transmitter signal modulation quality is tested, it is necessary to remove frequency deviation, initial skew andThe impact of the ISI that transmitting terminal formed filter brings.For signal R is received, it is by classical modulation signal MAP, wave filter in factThe ISI of input, modulation error E, and other transmitted noises n compositions, its relation is：
R=MAP+E+ISI+n
When quality test is modulated using measuring instrumentss, it is generally recognized that the impact caused by transmitted noise n can be neglectedSlightly.Therefore modulation error can be parsed using construction reference signal V., as shown in Fig. 1～2, detailed annotation is such as its concrete handling processUnder：
Step 1.1：The sampled signal that receiving terminal is received is synchronized, optimum sampling point SYNC is found out（It is synchronous）.
Step 1.2：According to optimum sampling point, extract optimum sampling all the way and receive signal R (n).For this reception signalSubsequent treatment, be divided into that two-way is parallel to be carried out：
Step 1.3.1：（1）Signal R (n) is received to first via optimum sampling, carry out successively frequency deviation/initial phase deflection correction,DC compensation, RMS（Root-Mean-Square, root-mean-square）Error compensation, and power normalization operation so that measurement signalReach RMS EVM statistics according to measurement agreement regulation to minimize.（2）The sampled signal obtained after minimizing error operation, needs JingThe measurement wave filter that measurement agreement specifies is crossed, the reception measurement signal for EVM measurements is finally givenNowWherein I is to measure the interference that wave filter may be introduced.
Step 1.3.2：（1）Receive signal R (n) to the second road optimum sampling, advanced line frequency partially/initial phase deflection correction, soCarry out joint-detection afterwards to this signal, parsing draws the symbolic information of signal.（2）And according to this symbolic information, re-modulate outClassical modulation signal MAP（Such as QPSK, 8PSK etc.）.（3）The signal MAP of re-modulation is made by filtering with the molding of transmitting terminal identicalRipple device, preferable transmission signal S (n) for obtaining.Preferable transmission signal S (n) has been introduced into and transmitting terminal one by formed filterThe ISI of sample, so the relation between each parameter is S (n)=MAP+ISI.Planisphere, the reflection being apparent from can be used hereinGo out ISI for the distribution influence rule of modulated signal.（4）Make the measurement filter that the measured agreement of preferable transmission signal S (n) specifiesRipple device, finally gives and receives reference signal V (n) for EVM measurements.Understand that V (n)=MAP+ISI+I, wherein I are measurement filteringThe interference that device may be introduced.
Step 1.4：Step 1.3.1 is obtainedThe V (n) obtained with step 1.3.2 is compared, you can adjustedError E (n) processed.Modulation quality test result " vector modulation error " can be calculated by E (n)（EVM）.Simultaneously as this mistakeDifference can show as vector form, therefore can show in the way of planisphere that this error is distributed.
Step 1.5：Step 1.3.2 it（2）In the classical modulation signal MAP that obtains can close with modulation error E (n)Into obtaining accurately reflecting the modulated signal constellation of " being affected by modulation error ", show for test instrumentation.
In addition to function above, using the modulation quality test system of this scheme, simulation input interference is also equipped with, and is hadThe standby function of accurately reflecting suffered interference effect in planisphere.Its handling process is also contained in Fig. 2, and step is as follows：
Step 2.1：All process of step 1.1～step 1.4 as described above are performed successively, obtain modulation error E(n)。
Step 2.2：Classical modulation signal MAP to gained in said process, adds simulaed interference signal, obtains signal U(n)。
Step 2.3：Signal U (n) is synthesized with E (n), you can to simulate the transmission modulated signal being disturbed.This signalTest instrumentation display output can be passed through.
Using above technical scheme, present invention achieves following purpose：
Propose it is a kind of be not based on matched filtering just can by measure wireless transmission signal modulation quality EVM in the way of, proposeA kind of basis is parsed modulation error vector and thus obtains modulation quality measurement knot based on the mode of reconstructed reference signalThe method of fruit EVM；A kind of method for proposing planisphere according to modulation error vector to observe modulation error distribution；ProposeOne kind synthesizes modulated signal constellation, and the side shown for test instrumentation according to modulation error vector classical modulation signalMethod；One kind is proposed according to modulation error vector and classical modulation signal, energy accurate simulation goes out the transmission modulation letter being disturbedNumber, and the method shown for test instrumentation planisphere.
The method that signal modulation mass measurement and planisphere show of realizing in the invention is employed, with following beneficial effectReally：
Method of the present invention according to reconstruct transmitting terminal reference signal, is compared with receiving terminal measurement signal and show that modulation is missedDifference vector, can be used for the measurement of modulation quality EVM, and can very easily draw the modulated signal of reflection modulation quality situationDeng planisphere；This scheme is avoided, and does not possess the mode of matched filtering in some communication standard transmitting terminals, it is impossible to be suitable for traditionThe limitation of mass measurement is modulated with Filtering Processing scheme；Meanwhile, this scheme can also be using the ginseng obtained in measurement procedureAmount, carries out signal interference simulation test, and can be to the modulated signal under the influence of various error states, using the mode of planisphereTo show measurement result, with wider range of application.
In this description, the present invention is described with reference to its specific embodiment.But it is clear that can still makeVarious modifications and alterations are without departing from the spirit and scope of the present invention.Therefore, specification and drawings are considered as illustrativeAnd it is nonrestrictive.