CN106199187A - A kind of method of testing of multi-tone signal relative phase - Google Patents

Abstract

A kind of method testing multi-tone signal relative phase of this disclosure of the invention, relates to the method for testing of the relative phase of multi-tone signal.A kind of method testing multi-tone signal relative phase, comprise build test platform, solve relative phase two part composition；It is essentially characterized in that the broadband signal mixing that each tone components of measured signal is gradually identical with same broadband signal or multiple baseband frequency spectrum information, and the intermediate frequency component after being mixed with sampling instrument collection, by calculating the relative phase obtaining measured signal.The present invention, during down coversion, uses broadband signal as mixed frequency signal, during follow-up calculating, by statistical average viewpoint, reduces calculating error.

Description

A kind of method of testing of multi-tone signal relative phase

Technical field

Modelled signal method of testing of the present invention, particularly relates to the method for testing of the relative phase of multi-tone signal.

Background technology

Along with growing to communication requirement of the mankind, communication technology is rapidly sent out towards the direction of multiband big data quantity Exhibition, instrument and the method for measuring communication system there has also been rapid progress.Multi-tone signal is usually applied in various communication system, example As, the local oscillation signal of compressed sensing receiver based on MWC framework, can be regarded as many messages with fixed frequency interval Number.But the relative phase measuring multi-tone signal annoyings the research worker of association area, becomes the important of related scientific research always Problem.

At present, the main method of testing of multi-tone signal relative phase has the mode directly measuring, using mixing with audiofrequency spectrometer Measurement etc. indirectly.There is random phase due to its local oscillation signal in common audiofrequency spectrometer, sampling first phase has a uncertainty, thus nothing Method measures the absolute phase of signal accurately.If the spectral range that the multi-tone signal of test is distributed is narrower, less than frequency spectrum The intermediate-frequency filter bandwidth of instrument, adjusts the frequency of the internal down coversion of audiofrequency spectrometer, and all sounds of multi-tone signal can be by audiofrequency spectrometer one Secondary property all samples, and thus can calculate the relative phase between each sound of multi-tone signal.But, if multi-tone signal institute The spectral range of distribution is wider, exceedes the bandwidth of audiofrequency spectrometer intermediate-frequency filter, and its relative phase directly can not be surveyed with audiofrequency spectrometer Amount.Another kind of method of testing be measurement indirectly, produces the multi-tone signal of one group of known relative phase as local oscillator, many with to be measured Tone signal is mixed, and adjusts the frequency of local oscillator each sound composition, it is ensured that the composition of each sound of measured signal can be mixed to relatively Low IF-FRE, and each sound do not produces aliasing at intermediate frequency, and the signal after mixing can pass through ADC device or audiofrequency spectrometer one Secondary property is sampled simultaneously, by calculating the relative phase that can obtain multi-tone signal.But, if measured signal multitone composition is too Many, and be distributed the widest frequency band, it is known that the multitone local oscillation signal of relative phase is not easy to generate, be difficult to measured signal is each After sound composition is down-converted to intermediate frequency simultaneously, and the calculating that carries out disposably simultaneously sampling.

The measured signal that the method for testing of the multi-tone signal relative phase that the present invention proposes is suitable for has the following characteristics that often One tone components is the most stable, and its signal entirety presents obvious periodicity, and multi-tone signal spectrum distribution is relatively wide, its Tone components is the most, it is impossible to directly measured by above-mentioned measuring method.The present invention uses and multi-tone signal is set up unification Basis reference, each tone components is measured respectively, processes finally according to sampled value calculating and obtains relative phase.The present invention both overcame The weakness that when direct audiofrequency spectrometer is measured, spectrum distribution to be measured is narrow, overcomes again indirectly measure that local oscillation signal is difficult to produce weak Point, it is possible to the relative phase of the test sophisticated signal that multitone composition is more and frequency is relatively wide.Further, the present invention is in down coversion During, use broadband signal as mixed frequency signal, during follow-up calculating, by statistical average viewpoint, Reduce calculating error.

Summary of the invention

It is an object of the invention to provide a kind of method testing multi-tone signal relative phase information, indirectly testing goes out frequency and divides Cloth is wider, multitone composition is compared with the relative phase of multi signal.

The technical scheme is that a kind of method testing multi-tone signal relative phase, comprise and build test platform, ask Solve relative phase two part composition；It is essentially characterized in that each tone components of measured signal gradually with same broadband signal or The broadband signal mixing that person's multiple baseband frequency spectrum information is identical, the intermediate frequency component after being mixed with sampling instrument collection, by calculating Obtain the relative phase of measured signal.

Thus a kind of method testing multi-tone signal relative phase of the present invention, the method includes:

Step 1: measured signal is divided into two-way, leads up to and accesses frequency mixer local oscillator end after the first gain control unit Mouthful, trigger signal generator is accessed on another road；

Step 2: trigger signal generator, according to the measured signal sent into, counts the cycle of this measured signal, every N number of Cycle produces one and triggers signal, and the value of N determined according to the cycle of ADC sampling length and multi-tone signal；Triggering signal divides For two-way, it is respectively fed to detect signal generator and ADC sampler part；

Step 3: send into the triggering signal of detection signal generator, controls detection signal generator and repeats to produce broadband letter Number, adjust the carrier frequency of this broadband signal so that it is corresponding with the frequency of one of them tone components of measured signal, then say This broadband signal is by accessing frequency mixer prevention at radio-frequency port after the second gain control unit；

Step 4: after the intermediate-freuqncy signal that frequency mixer produces is filtered by low pass filter, sends into ADC sampler；By sending into Signal is triggered on another road of ADC sampler part, controls the timing node of ADC sampler part record sampled data；Whenever ADC samples Device often receives one and triggers signal, just records the sampled data of certain length；

Step 5: the sample sequence value that i-th tone components is corresponding is denoted as y_i[n], to y_i[n] does Fourier transformation, obtains Y_iF (), arbitrarily chooses the sample sequence that wherein a tone components is corresponding as reference standard, is set to y_a[n], is in Fu it Leaf transformation obtains Y_aF (), does formula 1 computing

${\mathrm{Ae}}^{j\mathrm{\θ}}=\frac{y_i\left(f\right)*y_a{\left(f\right)}^H}{y_a\left(f\right)*y_a{\left(f\right)}^H}---\left(1\right)$

Wherein θ is i-th tone components and the phase contrast of a tone components.

Here as a example by the Fourier coefficient testing compressed sensing receiver local oscillation signal based on MWC framework, special to this The method of testing that profit is proposed illustrates.Compressed sensing receiver local oscillation signal based on MWC framework is the puppet of a high speed Random series, this pseudo-random sequence repeats with M bit, and therefore, it shows as equally spaced multitone on frequency domain Signal.Its coverage covers the widest in actual applications, the most hundreds of MHz tens GHz at most.Owing to passage and mixing etc. are non- The existence of desirable factors, there is distortion in Fourier coefficient, thus can not need it by being calculated Fourier coefficient Test, signal can be recovered accurately.But the method handle taking once to sample it is difficult to current method of testing So Fourier coefficient in wide frequency ranges directly tests out, it is also difficult to the multi-tone signal producing a kind of known phase is carried out Mixing test.But this patent is mentioned indirectly method of testing and be can solve the problem that this problem, obtain the relative of each Fourier coefficient Value.In experiment, what we tested is at frequency with the equally spaced multi-tone signal of 40MHz (pseudo-random sequence of compressed sensing receiver) Rate scope is the Fourier coefficient of 1800MHz-2000MHz.Have in this frequency range 1800MHz, 1840MHz, 1880MHz, 1920MHz, 1960MHz, 2000MHz six spectrum.With 1880MHz as reference, the amplitude of its Fourier coefficient is set to 1, phase place It is set to 0.After test, other spectrum relative amplitude as it is shown in figure 5, relative phase as shown in Figure 6.Each frequency tests 20 times, In terms of test result, the result fluctuation of test every time is the least, illustrates that test is to stablize repeatably, also demonstrates test result Reliability.

Accompanying drawing explanation

Fig. 1 is that multi-tone signal relative phase of the present invention tests system block diagram；

Fig. 2 is the frequency domain characteristic of multi-tone signal to be measured；

Fig. 3 is the frequency domain characteristic of test signal；

Fig. 4 is the signal IF_1 after low pass filter；

Fig. 5 multi-tone signal Fourier coefficient relative amplitude；

Fig. 6 multi-tone signal Fourier coefficient relative phase.

Detailed description of the invention

The present invention combines accompanying drawing and further illustrates；Instrument device used in the present invention, including measuring signal generator, touches Signalling generator, gain control unit (wide-band linearity), frequency mixer, low pass filter, ADC sampler part and data process Calculating instrument.Its system block diagram is as shown in Figure 1.

Concretely comprising the following steps of a kind of method testing multi-tone signal relative phase:

1, as shown in system block diagram 1, measuring table is built.

2, measured signal is defaulted as the relative phase of multi-tone signal, if multiple tone signal need to be measured, application bonder will Multiple tone signals are coupled into multi-tone signal.

3, by the signal generator in test platform, trigger signal generator, ADC sampler part, clock synchronization is carried out.

4, multi-tone signal is divided into two-way, leads up to after gain control unit, access the local oscillator port of frequency mixer, another Trigger signal generator is accessed on road.

5, trigger signal generator is according to the multi-tone signal sent into, and counts the cycle of this multi-tone signal, every N number of cycle Producing one and trigger signal, the value of N determined according to the cycle of ADC sampling length and multi-tone signal.Trigger signal and be divided into two Road, is respectively fed to signal generator and ADC sampler part.

6, sending into the triggering signal of signal generator, control signal generator repeats to produce broadband signal, i.e. signal and occurs Device often receives triggering signal, will regenerate the identical broadband signal of base-band information, adjust the load of this broadband signal Wave frequency, makes corresponding with the frequency of one of them tone components of multi-tone signal to be measured, and after mixing, its intermediate frequency component can pass through Low pass filter, now intermediate frequency component contains the phase information of this tone signal.

7, the broadband signal produced by signal generator is by after gain control unit, sends into the prevention at radio-frequency port of frequency mixer, And be mixed with assertive evidence signal, after the intermediate-freuqncy signal that mixing produces is filtered by low pass filter, send into ADC sampler part Analog input end.

8, signal is triggered on another road sending into ADC sampler part, controls the time segmentum intercalaris of ADC sampler part record sampled data Point.It is to say, trigger signal whenever ADC sampler part receives one, just record the sampled data of certain length.

9, repeat step 5-7, repeat all to change the carrier frequency of the broadband signal in step 5, with many messages to be measured every time Number a tone components correspondence, until all of tone components is all measured by correspondence.

10, by many groups sampled data of record, correlation computations instrument is used to calculate the relative phase of multi-tone signal.Tool Body calculates process: the sample sequence value that i-th tone components is corresponding is denoted as y_i[n], to y_i[n] does Fourier transformation, obtains Y_i F (), arbitrarily chooses the sample sequence that wherein a tone components is corresponding as reference standard, is set to y_a[n], is in Fu it Leaf transformation obtains Y_aF (), does formula 1 computing

${\mathrm{Ae}}^{j\mathrm{\θ}}=\frac{y_i\left(f\right)*y_a{\left(f\right)}^H}{y_a\left(f\right)*y_a{\left(f\right)}^H}---\left(2\right)$

Wherein θ is i-th tone components and the phase contrast of a tone components (reference value).

Its principle is as follows, and measured signal SS is multi-tone signal, measures multiple tone signal if needed, can use bonder First carry out coupling and obtain multi-tone signal.The feature of its multi-tone signal to be measured is, each tone components is the most stable, its signal Entirety presents obvious periodicity, and multi-tone signal spectrum distribution is relatively wide, and its tone components will be to more, its signal representation Form is

$\begin{array}{c}SS=A_1{e}^{{\mathrm{j\θ}}_1}{e}^{j*2{\mathrm{\πf}}_{1}t}+A_1{e}^{-{\mathrm{j\θ}}_1}{e}^{-j*2{\mathrm{\πf}}_{1}t}+A_2{e}^{{\mathrm{j\θ}}_2}{e}^{j*2{\mathrm{\πf}}_{2}t}+A_2{e}^{-{\mathrm{j\θ}}_2}{e}^{-j*2{\mathrm{\πf}}_{2}t}\\ +\mathrm{...}+A_n{e}^{{\mathrm{j\θ}}_n}{e}^{j*2{\mathrm{\πf}}_{n}t}+A_n{e}^{-{\mathrm{j\θ}}_n}{e}^{-j*2{\mathrm{\πf}}_{n}t}\end{array}---\left(3\right)$

In formula (2), A_i, i=1,2 ... n is real number, the amplitude of the Fourier coefficient after representation signal Fourier transformation, θ_i, i=1,2 ... n does not represent the phase place of Fourier coefficient, f_i, i=1,2 ... the load of each tone components in n representation signal respectively Wave frequency.The purpose of the present invention is exactly to obtain the relative value between each θ.

The signal SS form of expression on frequency domain, as shown in arrow in schematic diagram Fig. 2.

In system block diagram 1, in order to ensure the synchronicity of whole system, we by signal source, trigger signal generator, with And ADC sampler part carries out clock synchronization.First measured signal SS is divided into two-way, leads up to by LNA and attenuator group The gain control unit become, is adjusted to suitable scope by its amplitude and obtains SS1=G₁* ss, wherein G₁For gain coefficient.By SS1 Access the local oscillator input of frequency mixer.Owing to measured signal is multi-tone signal, so SS is periodic signal.The another one of SS is propped up Trigger signal generator, the periodicity of trigger signal generator record SS signal are accessed in road, every N number of cycle, send one and touch Signaling, the value of N determined according to the cycle of ADC sampling length and multi-tone signal.Trigger signal and be admitted to signal source and ADC Sampling device.Detection signal be signal bandwidth be the Broad-band Modulated Signal of B.Signal source receives triggering signal every time, always produces Raw base-band information identical detection signal, its carrier frequency can regulate change.First the carrier frequency of regulation detection signal Rate is f₁-f_a, the expression formula of detection signal is:

$RF1=sig\_B\_P*e^{j*2\mathrm{\π}(f_1-f_a)t}+\sin \_B\_N*e^{-j*2\mathrm{\π}(f_1-f_a)t}---\left(4\right)$

Wherein, B/2 < f_a<f_p-B/2, f_pCut-off frequency for low pass filter.Now, the form of expression is such as on frequency domain for RF1 In Fig. 3 trapezoidal shown in.Its power, by the gain control unit being made up of LNA and attenuator, is adjusted to suitably by RF1 Scope, the signal RF1_a=G after adjustment₂* RF1, wherein G₂For gain coefficient.RF1_a is sent into the prevention at radio-frequency port of frequency mixer, warp After crossing frequency mixer, measured signal is in frequency f₁The phase information of place's tone components, is included in intermediate frequency f_aIn the frequency spectrum at place, pass through By f after low pass filter_aThe frequency spectrum at place takes out, it is assumed that conversion gain is for assuming G₃For conversion gain, it is filtered After signal IF_1 expression formula as follows:

$IF\_1=G_1{G}_2{G}_3{A}_1*sig\_B\_P*e^{-{\mathrm{j\&theta;}}_1}{e}^{-j*2{\mathrm{\&pi;f}}_{a}t}+G_1{G}_2{G}_3{A}_1*sig\_B\_N*e^{-{\mathrm{j\&theta;}}_1}{e}^{j*2{\mathrm{\&pi;f}}_{a}t}---\left(5\right)$

Synchronize and trigger to synchronize and the periodicity of local oscillation signal owing to system has carried out clock, each test sample is joined Being duplicate with the local oscillator state of mixing, the carrier frequency adjusting the test signal that signal produces is f₂-f_a, with letter to be measured Number a tone components f₂Correspondence, test signal expression is:

$RF2=sig\_B\_P*e^{j*2\mathrm{\&pi;}(f_2-f_a)t}+sig\_B\_N*e^{-j*2\mathrm{\&pi;}(f_2-f_a)t}---\left(6\right)$

By gain control unit, it is mixed, filters, the intermediate frequency form of expression on frequency domain can be obtained as shown in Figure 4, its Expression formula is:

$IF\_2=G_1{G}_2{G}_3{A}_2*sig\_B\_P*e^{-{\mathrm{j\&theta;}}_2}{e}^{-j*2{\mathrm{\&pi;f}}_{a}t}+G_1{G}_2{G}_3{A}_2*sig\_B\_N*e^{-{\mathrm{j\&theta;}}_2}{e}^{j*2{\mathrm{\&pi;f}}_{a}t}---\left(7\right)$

Adjust the carrier frequency of test signal, repeat aforesaid operations, until all of tone components of measured signal is all surveyed Complete.

Here only positive frequency spectrum to IF_1 and IF_2 does ratio and can obtain:

$\frac{IF\_2}{IF\_1}=\frac{G_1{G}_2{G}_3{A}_2*RF\_P*e^{-{\mathrm{j\&theta;}}_2}}{G_1{G}_2{G}_3{A}_1*RF\_P*e^{-{\mathrm{j\&theta;}}_1}}=\frac{A_2}{A_1}*e^{j({\mathrm{\&theta;}}_1-{\mathrm{\&theta;}}_2)}---\left(8\right)$

So we just find in frequency f₁And f₂The relative phase θ of place's tone components₁-θ₂.It is pointed out that and use formula (8) method of the plural ratio expressed by can obtain preferable noiseproof feature, and relative phase is still θ₁-θ₂。

$\frac{IF\_2}{IF\_1}=\frac{IF\_2*{(IF\_1^{*})}^T}{IF\_1*{(IF\_1^{*})}^T}=\frac{A_2}{A_1}*e^{j({\mathrm{\&theta;}}_1-{\mathrm{\&theta;}}_2)}---\left(9\right).$

Claims (1)

1. the method testing multi-tone signal relative phase, the method includes:

Step 1: measured signal is divided into two-way, leads up to and accesses frequency mixer local oscillator port after the first gain control unit, separately Trigger signal generator is accessed on one road；

Step 2: trigger signal generator, according to the measured signal sent into, counts the cycle of this measured signal, every N number of cycle Producing one and trigger signal, the value of N determined according to the cycle of ADC sampling length and multi-tone signal；Trigger signal and be divided into two Road, is respectively fed to detect signal generator and ADC sampler part；

Step 3: send into the triggering signal of detection signal generator, controls detection signal generator and repeats to produce broadband signal, adjust The carrier frequency of this broadband signal whole so that it is corresponding with the frequency of one of them tone components of measured signal, then says this width Band signal is by accessing frequency mixer prevention at radio-frequency port after the second gain control unit；

Step 4: after the intermediate-freuqncy signal that frequency mixer produces is filtered by low pass filter, sends into ADC sampler；By sending into ADC Signal is triggered on another road of Sampling device, controls the timing node of ADC sampler part record sampled data；Whenever ADC sampler Part often receives one and triggers signal, just records the sampled data of certain length；

Step 5: the sample sequence value that i-th tone components is corresponding is denoted as y_i[n], to y_i[n] does Fourier transformation, obtains Y_i F (), arbitrarily chooses the sample sequence that wherein a tone components is corresponding as reference standard, is set to y_a[n], is in Fu it Leaf transformation obtains Y_aF (), does formula 1 computing

${\mathrm{Ae}}^{j\mathrm{\&theta;}}=\frac{y_i\left(f\right)*y_a{\left(f\right)}^H}{y_a\left(f\right)*y_a{\left(f\right)}^H}---\left(1\right)$

Wherein θ is i-th tone components and the phase contrast of a tone components.