CN110048787A - A kind of measurement filter selection method applied to Vector Signal Analysis - Google Patents
A kind of measurement filter selection method applied to Vector Signal Analysis Download PDFInfo
- Publication number
- CN110048787A CN110048787A CN201910269847.2A CN201910269847A CN110048787A CN 110048787 A CN110048787 A CN 110048787A CN 201910269847 A CN201910269847 A CN 201910269847A CN 110048787 A CN110048787 A CN 110048787A
- Authority
- CN
- China
- Prior art keywords
- filter
- evm
- measurement
- type
- value
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B17/00—Monitoring; Testing
- H04B17/30—Monitoring; Testing of propagation channels
- H04B17/309—Measuring or estimating channel quality parameters
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B17/00—Monitoring; Testing
- H04B17/30—Monitoring; Testing of propagation channels
- H04B17/309—Measuring or estimating channel quality parameters
- H04B17/336—Signal-to-interference ratio [SIR] or carrier-to-interference ratio [CIR]
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B17/00—Monitoring; Testing
- H04B17/30—Monitoring; Testing of propagation channels
- H04B17/382—Monitoring; Testing of propagation channels for resource allocation, admission control or handover
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Quality & Reliability (AREA)
- Monitoring And Testing Of Transmission In General (AREA)
Abstract
The present invention relates to a kind of measurement filter selection methods applied to Vector Signal Analysis.This method is based on the theory relation between the bit error rate and matched filter and the bit error rate and EVM, derivation is under equal conditions on the basis of the correlation of EVM and matched filter, " traversal " is used to find so that the highest measurement filter of EVM accuracy of measurement, this method not only can solve output equipment formed filter is known and Vector Signal Analyzer without corresponding measurement filter the case where, but also the situation that the formed filter that can solve vector signal output equipment is unknown.After the theoretical method is developed into common software, the select permeability for measuring filter live can be solved in real time, it is easy to operate, it is not necessarily to specialty background, suitable engineering site measurement.
Description
Technical field
The present invention relates to a kind of optimum measurement filter selection methods applied to Vector Signal Analysis.Belong to instrument and meter
Technical field.
Background technique
In digital communication systems, due to the filter action of transmitter and channel, receiving sequence, there is intersymbol interferences, connect
The target for receiving filter is to restore the base band pulse with maximum signal to noise ratio under the premise of no intersymbol interference, can be realized this
The optimum reception filter of a target is known as matched filter or correlator.When carrying out vector signal measurement, it is necessary to by vector
The formed filter of signal output apparatus and the measurement filter of Vector Signal Analyzer are matched, and will cause letter as mismatched
The loss of number energy and the measurement error for directly resulting in vector parameters to be measured (such as Error Vector Magnitude EVM) increases.And in fact,
The formed filter of vector signal output equipment is unknown and the formed filter of output equipment is known and Vector Signal Analyzer
The case where without corresponding measurement filter, is generally existing, and the measurement of standby vector signal is especially installed in spaceflight TT&C system spy
In.
Filter match problem is solved from measuring device in vector signal test process, reported optimum measurement filter
Wave device selection method is only a kind of: the software provided by apparatus manufacture is joined according to the formed filter of vector signal output equipment
Number is directed into measuring instrument after redesigning filter.It is measured again after designing filter by this method, measurement accuracy
It is high.But this method only for known to the formed filter of output equipment and Vector Signal Analyzer without corresponding measurement filter
Situation is invalid in the case of unknown for vector signal output equipment filter.In addition only a small number of manufacturers can provide software, and filter
The design of wave device is complex, and time-consuming, and professional knowledge is needed to accumulate.
Summary of the invention
It is a kind of applied to Vector Signal Analysis the technical problem to be solved by the present invention is to be provided for the above-mentioned prior art
Measurement filter selection method, the formed filter that not only can solve output equipment is known and Vector Signal Analyzer is without phase
The case where measurement filter answered, and the situation that the formed filter that can solve vector signal output equipment is unknown.
The present invention solves the above problems used technical solution are as follows: a kind of measurement applied to Vector Signal Analysis filters
Device selection method, the described method comprises the following steps:
Step 1: the theory relation of research matched filter and EVM
If the transfer function of linear filter is H (f), filter input x (t) is being superimposed for signal and noise, i.e.,
X (t)=s (t)+n (t) (1)
In formula:
S (t) ----signal expression, power spectral density function are S (f)；
N (t) --- the expression formula of-white Gaussian noise, bilateral power spectral density.
Then the output of filter can be expressed as:
Y (t)=s0(t)+n0(t) (2)
In t=t0Moment has:
The power level of noise N exported at this time0Are as follows:
Then linear filter is in t0The signal-to-noise ratio r at moment0Are as follows:
Seek r0Maximum linear filter, being attributed to ask in number makes (5) to reach optimal H (f).According to Wa Er perhaps
Hereby inequality:
And if only if A (f)=KB*(f) when, equal sign is set up.B*(f) be B (f) conjugate complex number, K is constant, then have:
Wherein:
E---- is the gross energy of signal s (t), and expression formula is
|S(f)|2The energy spectral density of ----be s (t).
Matched filter refers to the maximum linear filter of output signal-to-noise ratio.Theory analysis and it was verified that if filtering
The output of device can obtain maximum signal to noise ratio, the appearance of the optimal judgement signal of energy, so that the detection performance of system is improved,
That is, using matched filter, the bit error rate of system is minimum under square one.
Under white Gaussian noise environment, the bit error rate of the digital communication system under all kind of modulations mode and demodulation mode with
Eb/N0Relationship it is as shown in table 1:
The theoretical bit error rate under 1 all kind of modulations demodulation mode of table
According to the theoretical error rate calculation formula in table, can be roughly divided into two types.One kind is with Eb/N0For the Q letter of independent variable
Number, one kind is with-Eb/N0It is independent variable using e as the exponential function of the truth of a matter, two kinds of functions are in Eb/N0It is that dullness is passed when >=0
Subtraction function.
EVM and Eb/N0Shown in relationship such as formula (8) under white Gaussian noise environment:
Wherein:
SNR---- signal power to noise power ratio；
ESThe energy of ----symbol, unit mW；
EbThe energy of ----per bit, unit mW；
NsymbolThe bit number that ----each symbol contains；
It can be seen that E from formula (8)b/N0It is the monotonic decreasing function with EVM (actually EVM >=0) for independent variable, so
Bit error rate PeWith EVM monotonic increase.
It is the theoretical basis for finding matched filter above, that is, finds so that EVM measured value reaches the smallest measurement filtering
Device, certainly, the condition of establishment are that there are matched filters in measuring instrument.For matched filter is not present in measuring instrument
The unknown situation of the formed filter of situation perhaps output equipment is although search less than matched filter or not can determine that search
To filter whether be matched filter, but can find so that the EVM measured reaches the smallest filter, can make in this way
For measurement result as far as possible close to actual value, it is the indispensable means of engineering survey that measurement error reaches minimum under the limited conditions.
Step 2: optimum measurement filter is found using traversal
According to above-mentioned theory, filter is measured closer to matched filter, and the EVM of measurement is smaller, filters when being arranged to matching
When wave device, EVM value reaches minimum.This is also the theoretical basis that traversal finds optimum measurement filter.
The measuring process of traversal:
1. initializing filter type；
2. the value of rolloff-factor is continuously increased for stepping with rolloff-factor α for 0.05 starting point, 0.05, until rolloff-factor reaches
To 0.95, the EVM value (every time measurement take 3 times average) of each corresponding rolloff-factor is recorded；
3. changing filter type, step is repeated 2., until the filter type of measuring instrument is all completed；
The summation of EVM value is measured when 4. calculating each type filter, and is compared, the smallest filter is found out and be worth
(minimum value of the summation of the comparison EVM measured value of use rather than directly searching EVM, is in order to avoid due to measuring instrument to type
Device data fluctuations bring measurement error.Such as the measurement data curve of the filter of two types very close to, and one of them
The experiment curv of type filter is only smaller than other one in smallest point, and other points are all bigger than him, but this point is very close.This is aobvious
It is so as caused by the random error of measurement, integrally lesser measurement filter actually more closely matches filtering to EVM value
Device.).
5. finding out the minimum corresponding rolloff-factor of EVM measured value, corresponding filter in minimum and value filter type
Wave device type and rolloff-factor are the optimal measurement filter selection scheme that EVM measurement is carried out using the type instrument.
Due to use traversal find optimum measurement filter be related to calculate compare, measurement group number is more, process time compared with
It is long, and it is only applied to measuring device, therefore be suitble to apply automatic test.
Compared with the prior art, the advantages of the present invention are as follows:
The present invention is based on the theory relations between the bit error rate and matched filter and the bit error rate and EVM, derive same
Under the conditions of on the basis of the correlation of EVM and matched filter, use " traversal " to find so that EVM accuracy of measurement highest
Measurement filter, this method not only can solve output equipment formed filter is known and Vector Signal Analyzer is without corresponding
Measurement filter the case where, and the situation that the formed filter that can solve vector signal output equipment is unknown.By the reason
After developing by method into common software, the select permeability for measuring filter live can be solved in real time, it is easy to operate, without professional back
Scape is suitble to engineering site measurement.
Detailed description of the invention
Fig. 1 is test equipment connection figure in the embodiment of the present invention.
Fig. 2 is test equipment device connection diagram in the embodiment of the present invention.
Fig. 3 is experiment curv figure of the EVM under different filter types and rolloff-factor α in the embodiment of the present invention.
Specific embodiment
The present invention will be described in further detail below with reference to the embodiments of the drawings.
The present invention relates to a kind of measurement filter selection method applied to Vector Signal Analysis, this method uses traversal
Find optimum measurement filter.
Implementation process
(1) filter type is initialized；
(2) factor alpha is continuously increased for stepping for 0.05 starting point, 0.05 by the value of rolloff-factor with rolling, until rolloff-factor
Reach 0.95, records the EVM value (every time measurement take 3 times average) of each corresponding rolloff-factor；
(3) change filter type, repeat step 2., until the filter type of measuring instrument is all completed；
(4) summation of EVM value is measured when calculating each type filter, and is compared, the smallest filtering is found out and be worth
Device type.
(5) in minimum and value filter type, the smallest rolloff-factor of EVM measured value, corresponding filtering are found out
Device type and rolloff-factor are the optimal measurement filter selection scheme that EVM measurement is carried out using the type instrument.
Embodiment:
In order to verify the actual effect for using traversal to find optimum measurement filter, two groups of experiments have been carried out.One group real
Test is to search out matched filter for testing this method comprising matched filter in the filter type being directed in measuring instrument
Probability.Another set is to install standby, the unknown situation of the filter type of transmitter for special, uses optimum measurement for comparing
The measurement result difference of filter measurement and other filters.
Experiment 1:
Include matched filter for the filter type in measuring instrument, searches out matched filter for testing this method
Probability.
Test hardware condition and configuration:
(1) digital signal generator
Model: N5182B；
(2) Vector Signal Analyzer
Model: N9020A；
Using vector signal source N5182B as source, Vector Signal Analyzer N9020A is as measuring device.Equipment connection
As shown in Figure 1, N5182B output specified modulation signal is arranged after connecting instrument, (signal level is -70dBm, and signal-to-noise ratio is
6dB), filter and rolloff-factor are set, and (autotest program is in strict accordance with traversal above for operation automatic test program
Design) it is tested, obtained result is compared with the setting type of N5182B and (repeats 20 times, is selected altogether in 20 times
With 2 kinds of modulation types: BPSK and QPSK, four kinds of filter types: root raised cosine, rectangle, gaussian sum low pass, each roll-offs
Coefficient is all different), statistics searches out the probability of matched filter, searches out the probability of rolloff-factor, while searching out matching
The probability of filter and rolloff-factor.
After tested, the probability of matched filter is searched out, the probability of rolloff-factor is searched out and searches out matching filter simultaneously
The probability of wave device and rolloff-factor is 100%.
Experiment 2:
Standby, the unknown situation of the filter type of transmitter is installed for spy, uses optimum measurement filter for comparing
The measurement result difference of measurement and other filters.
Test hardware condition and configuration:
(1) special dress digital baseband equipment
Has QPSK modulation system, energy closed loop surveys the bit error rate certainly.
(2) Vector Signal Analyzer
Model: N9020A；
Certain type spy fills digital baseband equipment as test object, and (modulation system of the equipment is QPSK, the filter of output
It is arranged unknown), Vector Signal Analyzer N9020A is as measuring device.Device connection diagram is as shown in Fig. 2, digital baseband equipment
Output is divided into two-way by power splitter, is sent all the way to Vector Signal Analysis N9020A carrying out EVM test, another way loops back to base
Carrying device carries out error rate test.Wherein the 10MHz of N9020A reference crystal oscillator output be connected to digital baseband equipment reference it is defeated
Enter and (reduces the factor for causing measurement error as far as possible).After connecting equipment, automatic test software is run, test is completed
Afterwards, EVM minimum value when directly finding out the measurement filter using each type in EXCEL (including uses optimum measurement to filter
EVM value when wave device).Meanwhile digital baseband equipment carries out error rate test, records the ber value of test.It is every according to using
Demodulation losses (the demodulation damage of the receiver section of EVM minimum value and digital baseband equipment when the measurement filter of a type
Losing is 2.5dB) its theoretic bit error rate is calculated, the theoretical bit error rate being calculated is compared with the actually measured bit error rate
Compared with.The mode for calculating the theoretical bit error rate is as follows:
Step 1: EVM being substituted into formula (8) and calculates SNR value；
Step 2: after SNR is subtracted 2.5dB (demodulation losses), in the practical EVM to be converted when receiving demodulation according to formula (8)
Value；
Step 3: the relevant solution of the QPSK modulation system in practical EVM value substitution table 1 when the reception that conversion is obtained demodulates
The error rate calculation formula of tune obtains formula (9), calculates the theoretical bit error rate according to formula (9).
The comparison diagram for measuring EVM using traversal is as shown in Figure 3.Can intuitively it find out from figure, EVM and value are the smallest
When be that the smallest EVM value is α when using root raised cosine filter being 0.5, therefore using N9020A to the digital baseband equipment
The optimum measurement filter that measures of QPSK modulation output be root raised cosine filter, α 0.5.Every kind will be surveyed below
It measures the corresponding EVM minimum value of filter and calculates the bit error rate by above step, and be compared with actually measured ber value,
Comparison result is as shown in table 2.From table it will be seen that when using optimum measurement filter (root raised cosine filter,
α is that 0.5), the theoretical bit error rate of estimation is closest to the actual bit error rate.In fact, the bit error rate of estimation is bigger than actual measurement,
This also illustrates the optimum measurement filter that we search out and non-matched filter, because, if it is matched filter, the bit error rate
Estimated value should be smaller than measured value (actual test can not reach theoretical level).Simultaneously, it should also be noted that although
The optimum measurement filter searched out in limited range can not achieve the effect that matched filter, still, use what is searched out
It is best under limited conditions that optimum measurement filter, which measures,.
Bit error rate estimation value and actual comparison table under the different measurement filters of table 2
In addition to the implementation, all to use equivalent transformation or equivalent replacement the invention also includes there is an other embodiments
The technical solution that mode is formed should all be fallen within the scope of the hereto appended claims.
Claims (2)
1. a kind of measurement filter selection method applied to Vector Signal Analysis, it is characterised in that: the method includes following
Step:
Step 1: the theory relation of research matched filter and EVM
If the transfer function of linear filter is H (f), filter input x (t) is being superimposed for signal and noise, i.e.,
X (t)=s (t)+n (t) (1)
In formula:
S (t) ----signal expression, power spectral density function are S (f)；
N (t) --- the expression formula of-white Gaussian noise, bilateral power spectral density；
Then the output of linear filter can be expressed as:
Y (t)=s0(t)+n0(t) (2)
In t=t0Moment, the power level of noise N of output0Are as follows:
Then linear filter is in t0The signal-to-noise ratio r at moment0Are as follows:
Matched filter refers to the maximum linear filter of output signal-to-noise ratio, obtains r according to Quwards Inequality0Maximum value
Are as follows:
Wherein:
E---- is the gross energy of signal s (t), and expression formula is
|S(f)|2The energy spectral density of ----be s (t)；
According to theoretical error rate calculation formula, EVM and Eb/N0Shown in relationship such as formula (8) under white Gaussian noise environment:
Wherein:
SNR---- signal power to noise power ratio；
ESThe energy of ----symbol, unit mW；
EbThe energy of ----per bit, unit mW；
NsymbolThe bit number that ----each symbol contains；
It can be seen that E from formula (8)b/N0It is the monotonic decreasing function using EVM as independent variable, so bit error rate PeWith EVM dullness
It is incremented by；
Step 2: finding optimum measurement filter using traversal
According to above-mentioned theory, filter is measured closer to matched filter, and the EVM of measurement is smaller, when being arranged to matched filter
When, EVM value reaches minimum；
The measuring process of traversal:
1. initializing filter type；
2. the EVM value of each corresponding rolloff-factor of record；
3. changing filter type, step is repeated 2., until the filter type of measuring instrument is all completed；
The summation of EVM value is measured when 4. calculating each type filter, and is compared, the smallest filter class is found out and be worth
Type；
5. finding out the minimum corresponding rolloff-factor of EVM measured value, corresponding filter in minimum and value filter type
Type and rolloff-factor are the optimal measurement filter selection scheme that EVM measurement is carried out using the type instrument.
2. a kind of measurement filter selection method applied to Vector Signal Analysis according to claim 1, feature exist
In: the value of rolloff-factor is continuously increased for stepping with rolloff-factor α for 0.05 starting point in step 2,0.05, until rolloff-factor
Reach 0.95.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910269847.2A CN110048787A (en) | 2019-04-04 | 2019-04-04 | A kind of measurement filter selection method applied to Vector Signal Analysis |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910269847.2A CN110048787A (en) | 2019-04-04 | 2019-04-04 | A kind of measurement filter selection method applied to Vector Signal Analysis |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN110048787A true CN110048787A (en) | 2019-07-23 |
Family
ID=67276170
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201910269847.2A Pending CN110048787A (en) | 2019-04-04 | 2019-04-04 | A kind of measurement filter selection method applied to Vector Signal Analysis |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN110048787A (en) |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2907090Y (en) * | 2005-11-23 | 2007-05-30 | 中兴通讯股份有限公司 | Multi-carrier signal generation device |
| CN101299600A (en) * | 2007-04-30 | 2008-11-05 | 大唐移动通信设备有限公司 | Design method for digital filter based on OFDM system |
| US20150155955A1 (en) * | 2013-12-04 | 2015-06-04 | Realtek Semiconductor Corp. | Calibration method and calibration apparatus for calibrating mismatch between i-path and q-path of transmitter/receiver |
| CN106982085A (en) * | 2016-01-15 | 2017-07-25 | 上海交通大学 | The robust transceiver design method that block diagonalization is aided in multiple cell mimo system |
| CN109067677A (en) * | 2018-08-31 | 2018-12-21 | 中国人民解放军63686部队 | A kind of adjustable EVM vector signal production method based on white Gaussian noise |
-
2019
- 2019-04-04 CN CN201910269847.2A patent/CN110048787A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2907090Y (en) * | 2005-11-23 | 2007-05-30 | 中兴通讯股份有限公司 | Multi-carrier signal generation device |
| CN101299600A (en) * | 2007-04-30 | 2008-11-05 | 大唐移动通信设备有限公司 | Design method for digital filter based on OFDM system |
| US20150155955A1 (en) * | 2013-12-04 | 2015-06-04 | Realtek Semiconductor Corp. | Calibration method and calibration apparatus for calibrating mismatch between i-path and q-path of transmitter/receiver |
| CN106982085A (en) * | 2016-01-15 | 2017-07-25 | 上海交通大学 | The robust transceiver design method that block diagonalization is aided in multiple cell mimo system |
| CN109067677A (en) * | 2018-08-31 | 2018-12-21 | 中国人民解放军63686部队 | A kind of adjustable EVM vector signal production method based on white Gaussian noise |
Non-Patent Citations (2)
| Title |
|---|
| 李晓峰 等: "《通信原理（第2版）》", 31 August 2014 * |
| 杨筱 等: "矢量信号分析中匹配滤波器的参数寻优与仿真", 《计算机仿真》 * |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN106646546A (en) | Multi-dimensional fast acquisition method and system for satellite signals | |
| CN103278825B (en) | Method for determining satellite navigation signal quality evaluation parameters | |
| CN102594393A (en) | Universal pseudocode synchronization system of comprehensive satellite baseband equipment | |
| CN106230475B (en) | One kind being based on Tong detectors pseudo-code Doppler effect correction catching method and device | |
| CN109617560A (en) | A kind of I/Q signal compensation for calibrating errors method | |
| CN110071738A (en) | Spread-spectrum signal based on more pseudo-code branch receivers de-spreads tracking | |
| CN110138698B (en) | Initial phase joint estimation method and device for frequency offset of high-order modulation linear mixed signal | |
| CN112235215B (en) | Wireless channel detection method, storage medium and terminal equipment | |
| CN109412644B (en) | Doppler frequency estimation method for direct sequence spread spectrum MSK signal | |
| CN103297924A (en) | Novel positioning fingerprint design method and indoor positioning system based on channel estimation | |
| CN113702901B (en) | Cross-correlation time delay estimation method based on signal correlation enhancement | |
| CN110336583A (en) | A kind of quick catching device and method of Direct Sequence Spread Spectrum Signal | |
| CN112910533B (en) | Broadband signal array system with parallel structure | |
| CN107621643B (en) | Method for accurately resolving relevant domain parameters suitable for navigation signal quality evaluation | |
| CN107070496B (en) | Real-time synchronization acquisition equipment and method based on partial matched filter algorithm | |
| CN110048787A (en) | A kind of measurement filter selection method applied to Vector Signal Analysis | |
| EP0487701A1 (en) | Signal acquisition | |
| CN105245247A (en) | Adaptive threshold controller and control method, direct sequence spread spectrum signal detection method and circuit | |
| CN112327332A (en) | Pseudo satellite signal quality analysis device and method based on USRP | |
| US7308021B2 (en) | Method in the synchronization of a receiver, and a receiver | |
| CN110290084B (en) | Short wave channel blind symbol synchronization method based on data frequency energy peak value | |
| CN111510409A (en) | Method and system for estimating space-based opportunistic signal doppler using BPSK data | |
| CN115865127B (en) | Parameter estimation and demodulation method for direct-spread signal | |
| CN109120562B (en) | MFSK signal frequency estimation method based on spectrum accumulation matching | |
| CN108900210B (en) | Method and system for eliminating parallel interference of multimode measurement and control signals |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| RJ01 | Rejection of invention patent application after publication | ||
| RJ01 | Rejection of invention patent application after publication |
Application publication date: 20190723 |