CN105099971A - Processing method and system of nonlinear distortion signals - Google Patents

Abstract

The invention discloses a processing method and system of nonlinear distortion signals, and belongs to the technical field of communications, for solving the technical problem of nonlinear distortion after signals are modulated by a modulator in the prior art. The processing method of the nonlinear distortion signals comprises the following steps: obtaining the nonlinear distortion signals, wherein the nonlinear distortion signals are digital signals and are modulated through two double-tone signals; obtaining an intermodulation distortion compensation coefficient, and performing intermodulation distortion compensation on the nonlinear distortion signals; separating the nonlinear distortion signals subjected to the intermodulation distortion compensation to obtain two three-order cross modulation distortion signals, wherein each three-order cross modulation distortion signal is corresponding to a double-tone signal; and obtaining two three-order coupling coefficients, respectively performing three-order cross modulation distortion compensation on the two three-order cross modulation distortion signals, and then through combination with the nonlinear distortion signals after the intermodulation distortion compensation, obtaining two linear signals.

Description

A kind of processing method of nonlinear distortion signal and system

Technical field

The present invention relates to communication technical field, specifically, relate to a kind of processing method and system of nonlinear distortion signal.

Background technology

In order to meet data capacity sustainable growth in the urgent need to, support that the wide-band communication system of high-speed transfer becomes study hotspot.Generally speaking, by carrier frequency being extended in millimeter wave or Terahertz frequency band, the high speed performance of communication system can be realized.

Analog optical link, be intended to realize the sophisticated functions that simple microwave regime is difficult to realization, there is the characteristics such as high frequency, large bandwidth, low cost, electromagnetism interference, in addition, it can also overcome the limited bottleneck of traditional electrical signal transacting picking rate, is therefore considered to the best mode being applied to wide-band communication system process ultra-wide band radio-frequency signal.

But due to the effect of modulator unintentional nonlinearity, the performance of analog optical link is very easily subject to the impact of nonlinear distortion.In wide-band communication system, main type of distortion has harmonic distortion, third order intermodulation distortion and intermodulation distortion, exactly because the existence of above distortion, the severe exacerbation Spurious Free Dynamic Range of communication system, so, seek effective nonlinear distortion suppressing method very crucial for the Spurious Free Dynamic Range promoting optical link.

Generally speaking, harmonic distortion distance radio-frequency carrier is comparatively far away, selects suitable filter just can remove easily, can not affect inband signaling again.And third order intermodulation distortion distance radio-frequency carrier is comparatively near, be difficult to by filter filtering.And in the optical link system of ultra broadband, multicarrier, intermodulation distortion is identical with third order intermodulation distortion magnitude, even if any two radio frequency carrier frequency are spaced far apart, link still can be subject to the impact of this intercarrier intermodulation distortion, namely the signal carried on certain carrier wave can produce one " shadow " at another carrier wave place, and this shadow is in the bandwidth of operation of another carrier wave, cannot filtering removes.Therefore, the common suppression of multiple nonlinear distortion and compensation are ultra broadbands, high performance communication system needs the problem of solution badly.

Summary of the invention

The object of the present invention is to provide a kind of processing method and system of nonlinear distortion signal, occur the technical problem of nonlinear distortion with the signal after solving modulators modulate of the prior art.

First aspect present invention provides a kind of processing method of nonlinear distortion signal, and the method comprises:

Obtain nonlinear distortion signal, described nonlinear distortion signal is digital signal, through the modulation of two two-tone signals;

Obtain intermodulation distortion penalty coefficient, intermodulation distortion compensation is carried out to described nonlinear distortion signal;

The nonlinear distortion signal compensated through intermodulation distortion is separated, obtains two third order intermodulation distorted signals, the corresponding two-tone signal of each third order intermodulation distorted signal;

Obtain two three rank matching factors, respectively third order intermodulation distortion compensation is carried out to two third order intermodulation distorted signals, and the nonlinear distortion signal after compensating in conjunction with intermodulation distortion, obtain the linearizing signal of two-way.

Further, before acquisition nonlinear distortion signal, also comprise:

Obtain two local oscillation signals, down-converted is carried out to described nonlinear distortion signal, by described nonlinear distortion signal frequency conversion to its intermediate frequency or base band.

Further, described intermodulation distortion penalty coefficient depends on the working point utilizing two two-tone signals to modulate to obtain the Mach of nonlinear distortion signal to increase Dare modulator.

Further, obtain intermodulation distortion penalty coefficient, intermodulation distortion compensation carried out to described nonlinear distortion signal and comprises:

Bandpass filtering treatment and low-pass filtering treatment are carried out to described nonlinear distortion signal, obtains fundamental frequency item and the base band item of described nonlinear distortion signal respectively;

Obtain intermodulation distortion penalty coefficient;

Utilize small signal approximation, based on obtained intermodulation distortion penalty coefficient, intermodulation distortion compensation is carried out to described base band item and described fundamental frequency item.

Further, obtain two three rank matching factors, respectively third order intermodulation distortion compensation is carried out to two third order intermodulation distorted signals, and the nonlinear distortion signal after compensating in conjunction with intermodulation distortion, obtain the linearizing signal of two-way and comprise:

Respectively the process of squared value is carried out to two third order intermodulation distorted signals;

Respectively low-pass filtering treatment is carried out to two third order intermodulation distorted signals through square value process;

Obtain two three rank matching factors, respectively the third order intermodulation distorted signal after low-pass filtering is processed, obtain two three rank compensating signals;

Nonlinear distortion signal after being compensated in conjunction with intermodulation distortion by two three rank compensating signals respectively, obtains the linearizing signal of two-way and exports.

Present invention offers following beneficial effect: in the embodiment of the present invention, by obtaining intermodulation distortion factor and the three rank matching factors of nonlinear distortion signal, the distortion that the nonlinear distortion that the inherent nonlinearity increasing Dare modulator because of Mach is produced and digital signal processor produce is cancelled out each other, reach the object suppressing distortion, improve the dynamic range of analog optical link.

Second aspect present invention provides a kind for the treatment of system of nonlinear distortion signal, and described nonlinear distortion signal increases Dare modulator by first Mach to produce, and described system comprises photodetector, data collecting card and digital signal processor,

Described photodetector is used for the nonlinear distortion signal for analog signal to be converted to digital signal, and described nonlinear distortion signal is the modulation of digital signal two two-tone signals;

Described data collecting card is for being retrieved as the nonlinear distortion signal of digital signal;

Described digital signal processor comprises: intermodulation distortion compensating module and third order intermodulation distortion compensation module,

Described intermodulation distortion compensating module, for obtaining intermodulation distortion penalty coefficient, carries out intermodulation distortion compensation to described nonlinear distortion signal;

Described third order intermodulation distortion compensation module is used for the nonlinear distortion signal compensated through intermodulation distortion to separate, and obtains two third order intermodulation distorted signals, the corresponding two-tone signal of each third order intermodulation distorted signal; Obtain two three rank matching factors, respectively third order intermodulation distortion compensation is carried out to two third order intermodulation distorted signals, and the nonlinear distortion signal after compensating in conjunction with intermodulation distortion, obtain the linearizing signal of two-way.

Further, this system also comprises second Mach and increases Dare modulator,

Described second Mach increasing Dare modulator for obtaining two local oscillation signals, utilizing two local oscillation signals to carry out down-converted to described nonlinear distortion signal, by described nonlinear distortion signal frequency conversion to its intermediate frequency or base band;

Described photodetector is used for being converted to digital signal by through down-converted and for the nonlinear distortion signal of analog signal.

Further, described intermodulation distortion penalty coefficient depends on the described first Mach of working point increasing Dare modulator utilizing two two-tone signals to modulate to obtain described nonlinear distortion signal.

Further, described intermodulation distortion compensating module comprises:

Bandpass filtering submodule, for carrying out bandpass filtering treatment to described nonlinear distortion signal, obtains the fundamental frequency item of described nonlinear distortion signal;

Low-pass filtering submodule, for carrying out low-pass filtering treatment to described nonlinear distortion signal, obtains the base band item of described nonlinear distortion;

Obtain submodule, for obtaining intermodulation distortion penalty coefficient;

Compensating submodule, for utilizing small signal approximation, based on obtained intermodulation distortion penalty coefficient, intermodulation distortion compensation being carried out to described base band item and described fundamental frequency item.

Further, described third order intermodulation distortion compensation module comprises:

First bandpass filtering submodule and the second bandpass filtering submodule, for carrying out bandpass filtering treatment to the nonlinear distortion signal compensated through intermodulation distortion respectively, obtain two third order intermodulation distorted signals;

First square of process submodule and second square of process submodule, for carrying out the process of squared value to two third order intermodulation distorted signals respectively;

First low-pass filtering submodule and the second low-pass filtering submodule, for carrying out low-pass filtering treatment to two third order intermodulation distorted signals through square value process respectively;

First third order intermodulation distortion compensation submodule and the second third order intermodulation distortion compensation submodule, for processing the third order intermodulation distorted signal after low-pass filtering respectively, obtain two three rank compensating signals;

First signal output sub-module and secondary signal output sub-module, for respectively by two three rank compensating signals in conjunction with intermodulation distortion compensate after nonlinear distortion signal, obtain the linearizing signal of two-way and export.

Other features and advantages of the present invention will be set forth in the following description, and, partly become apparent from specification, or understand by implementing the present invention.Object of the present invention and other advantages realize by structure specifically noted in specification, claims and accompanying drawing and obtain.

Accompanying drawing explanation

In order to be illustrated more clearly in the technical scheme in the embodiment of the present invention, accompanying drawing required in describing is done simple introduction below to embodiment:

Fig. 1 is the schematic flow sheet of the processing method of nonlinear distortion signal in the embodiment of the present invention;

Fig. 2 is the structural representation of the treatment system of nonlinear distortion signal in the embodiment of the present invention;

Fig. 3 is the structural representation of the digital signal processor in the embodiment of the present invention;

Fig. 4 is the frequency spectrum of the nonlinear distortion signal in the embodiment of the present invention;

Fig. 5 is the frequency spectrum of the nonlinear distortion signal through intermodulation distortion compensation in the embodiment of the present invention;

Fig. 6 is the frequency spectrum of a third order intermodulation distorted signal after third order intermodulation distortion compensation in the embodiment of the present invention;

Fig. 7 is the frequency spectrum of another third order intermodulation distorted signal after third order intermodulation distortion compensation in the embodiment of the present invention.

Embodiment

Describe embodiments of the present invention in detail below with reference to drawings and Examples, to the present invention, how application technology means solve technical problem whereby, and the implementation procedure reaching technique effect can fully understand and implement according to this.It should be noted that, only otherwise form conflict, each embodiment in the present invention and each feature in each embodiment can be combined with each other, and the technical scheme formed is all within protection scope of the present invention.

Digital Signal Processing is by the method to various analog optical link performance prediction, carrys out the non-ideal characteristic of the signal that compensating analog optical link exports, has higher flexibility ratio, greatly reduces the complexity of system hardware.Therefore, this technology is incorporated in analog optical link system and can improves system linearity degree greatly.

Therefore, embodiments provide a kind of processing method of the nonlinear distortion signal based on Digital Signal Processing, as shown in Figure 1, the method comprises:

Step S101, acquisition nonlinear distortion signal, nonlinear distortion signal is digital signal, through the modulation of two two-tone signals.

Step S102, acquisition intermodulation distortion penalty coefficient, carry out intermodulation distortion compensation to nonlinear distortion signal.

Step S103, by the nonlinear distortion signal that compensates through intermodulation distortion separately, obtains two third order intermodulation distorted signals, each third order intermodulation distorted signal correspondence one two-tone signal.

Step S104, acquisition two three rank matching factors, carry out third order intermodulation distortion compensation to two third order intermodulation distorted signals respectively, and the nonlinear distortion signal after compensating in conjunction with intermodulation distortion, obtain the linearizing signal of two-way.

In the embodiment of the present invention, by obtaining intermodulation distortion factor and the three rank matching factors of nonlinear distortion signal, the distortion that the nonlinear distortion that the inherent nonlinearity increasing Dare modulator because of Mach is produced and digital signal processor produce is cancelled out each other, reach the object suppressing distortion, improve the dynamic range of analog optical link.

As shown in Figure 2, the light carrier that LASER Light Source L produces is through the first Polarization Controller (PolarizationController, be called for short PC) adjustment after enter first Mach and increase Dare modulator (Mach-ZehnderModulator is called for short MZM).First Mach increases Dare modulator (hereinafter referred to as MZM1) and is loaded with broadband rf signal, and broadband rf signal is made up of two two-tone signals.Therefore, after light carrier enters MZM1, modulated by the broadband rf signal that MZM1 loads.Wherein, the effect of a PC is adjusted to consistent with the main shaft of MZM1 by the light carrier that L exports, and now MZM1 is operated in low bias state.Obviously, in the embodiment of the present invention, because MZM1 utilizes two-way two-tone signal to regulate light carrier simultaneously, obtain multicarrier radiofrequency signal.

Owing to using digital signal processor (DigitalSignalProcessor, be called for short DSP) nonlinear distortion signal is processed, need first to gather nonlinear distortion signal by data collecting card (Analog-to-DigitalConverter is called for short ADC).Be subject to the problem of ADC bandwidth restriction, DSP cannot complete the processing capacity of the nonlinear distortion signal of high frequency.

Therefore, the multicarrier radiofrequency signal of the nonlinear distortion that MZM1 exports enters the treatment system of the nonlinear distortion signal that the embodiment of the present invention provides, as shown in Figure 2, nonlinear distortion signal, first through the adjustment of the 2nd PC, enters the 2nd MZM (hereinafter referred to as MZM2).MZM2 loads two local oscillation signals, and the equivalence that can realize frequency spectrum in area of light is moved, and by nonlinear distortion signal frequency conversion higher for frequency to intermediate frequency or base band, realizes the down-converted to nonlinear distortion signal.In the embodiment of the present invention, what MZM1 exported is multicarrier radiofrequency signal, therefore MZM2 can receive multicarrier radiofrequency signal simultaneously, and utilizes two local oscillation signal down-converted each road carrier radio frequency signal wherein simultaneously, realizes the down-conversion of multicarrier radiofrequency signal.Without using multiple converter plant, separately linearisation is carried out to each carrier radio frequency signal, reduce complexity and the cost of this treatment system.

Concrete, the effect of the 2nd PC is adjusted to consistent with the main shaft of MZM2 by the light that MZM1 exports.After MZM2, the intermediate-freuqncy signal obtained directly is carried out opto-electronic conversion, after ADC gathers by photodetector (PhotoconductiveDetector is called for short PD), analog signal is converted into digital signal, exports to digital signal processor and carry out follow-up digital process.Obviously, in the embodiment of the present invention, only need an ADC can realize, for the process of multicarrier radiofrequency signal, reception, being conducive to the complexity and the cost that reduce treatment system further.

By realizing equivalent frequency spectrum shift in area of light, high-frequency signal being converted to intermediate frequency or baseband signal, follow-up signal transacting can being convenient to further, greatly reduce the difficulty of subsequent treatment and the bandwidth requirement to the hardware device such as ADC, digital signal processor.

In the embodiment of the present invention, in order to realize the compensation to nonlinear distortion signal, as shown in Figure 3, digital signal processor is formed primarily of following two parts: intermodulation distortion compensating module and third order intermodulation distortion compensation module.Wherein, intermodulation distortion compensating module is responsible for the suppression, the compensation process that carry out intermodulation distortion (Cross-overModulationDistortion is called for short XMD); Third order intermodulation distortion module is responsible for the process of inhibition of third order intermodulation distortion (3rd.orderIntermodulationDistortion is called for short IMD3).Nonlinear distortion signal, through above two resume module, just can obtain linearizing restituted signal.

The concrete theory analysis process of nonlinear distortion signal being carried out to intermodulation distortion compensation is as follows:

It is ω that the broadband rf signal of injection MZM1 comprises some center angular frequency _kthe passband signals of signal, therefore broadband rf signal V (t) can be expressed from the next:

$V\left(t\right)=\underset{k}{\Σ}{\mathrm{\ρ}}_k\left(t\right)sin\left({\mathrm{\ω}}_{k}t\right)---\left(1\right)$

Wherein, ρ _kt amplitude envelope that () is passband signals.

For traditional intensity modulated-direct-detection analog optical link, the transfer function of MZM can be expressed as follows:

Wherein, for responsiveness, the V of photodetector _πfor angle of eccentricity, P that the half-wave voltage of MZM, θ are MZM ₀for input optical power, the α of light carrier _mZMfor the photoelectric current that the loss of MZM, I (t) detect for photodetector.

After down-converted, nonlinear distortion signal has been shifted to intermediate frequency, formula (1) is substituted into formula (2) and carries out Bessel function expansion, obtaining the base band item S of nonlinear distortion signal respectively ₀with fundamental frequency item S _k, embody as follows:

$S_0\left(t\right)\∝1+cos\mathrm{\θ}\underset{p}{\Π}{J}_0\left({\mathrm{\β\ρ}}_p\right)---\left(3\right)$

$S_k\left(t\right)\∝\underset{p}{\Π}{J}_0\left({\mathrm{\β\ρ}}_p\right)\frac{J_1\left({\mathrm{\β\ρ}}_k\right)}{J_0\left({\mathrm{\β\ρ}}_k\right)}sin\left({\mathrm{\ω}}_{IF}t\right)---\left(4\right)$

Wherein, β is the modulation depth of MZM1, is defined as j _n(*) be a class n rank Bessel function, ω _iFfor exporting the intermediate frequency of the signal of telecommunication.Obviously, base band item S ₀for DC terms, fundamental frequency item S _kfor single order item.

From formula (3) and (4), ∏ J ₀(β ρ _p) be non-linear intermodulation distortion item, J ₁(β ρ _k) be Nonlinear Intermodulation Distortion item.

First eliminated the impact of intermodulation distortion by the structure of numeric field penalty function, utilize small signal approximation, and suppose that following intermodulation distortion compensates formula and sets up:

$S_{xmc}\left(t\right)=s_0^{\mathrm{\γ}}\·S_k\∝\left\{\left(1-\frac{\mathrm{\γ}\cos \mathrm{\θ}}{4(1+\cos \mathrm{\θ})}\underset{p}{\mathrm{\Σ}}{\mathrm{\β}}^2{\mathrm{\ρ}}_p^2\right)\left(1-\frac{1}{4}\underset{p}{\mathrm{\Σ}}{\mathrm{\β}}^2{\mathrm{\ρ}}_p^2\right)\frac{J_1\left({\mathrm{\β\ρ}}_k\right)}{J_0\left({\mathrm{\β\ρ}}_k\right)}\right\}\sin \left({\mathrm{\ω}}_{IF}t\right)---\left(5\right)$

As can be seen from formula (5), when intermodulation distortion penalty coefficient γ meets following numerical relation, the intermodulation distortion of intercarrier can be inhibited completely in theory:

$\mathrm{\γ}=-\frac{1+cos\mathrm{\θ}}{\cos \mathrm{\θ}}---\left(6\right)$

From formula (6), intermodulation distortion penalty coefficient γ depends on the impact of the working point of MZM1, with other characteristic parameters without any relation.Therefore by the acquisition of the working point of MZM1, determine unique intermodulation distortion penalty coefficient γ, digital intermodulation distortion compensation can be completed at numeric field.

Utilize as lower aprons: further to inhibit the signal of XMD to launch, obtain as follows:

$S_{xmc}\left(t\right)\∝\frac{J_1\left({\mathrm{\β\ρ}}_k\right)}{J_0\left({\mathrm{\β\ρ}}_k\right)}sin\left({\mathrm{\ω}}_{IF}t\right)\≈\frac{1}{2}\[1+\frac{1}{8}{\left({\mathrm{\β\ρ}}_k\right)}^2\]\left({\mathrm{\β\ρ}}_k\right)sin\left({\mathrm{\ω}}_{IF}t\right)---\left(7\right)$

In order to realize said process, as shown in Figure 3, being responsible for carrying out the suppression of XMD, the intermodulation distortion compensating module of compensation comprises: bandpass filtering submodule, for carrying out bandpass filtering treatment to nonlinear distortion signal, obtaining the fundamental frequency item of nonlinear distortion signal; Low-pass filtering submodule, for carrying out low-pass filtering treatment to nonlinear distortion signal, obtains the base band item of nonlinear distortion; Obtain submodule, for obtaining intermodulation distortion penalty coefficient; Compensating submodule, for utilizing small signal approximation, based on obtained intermodulation distortion penalty coefficient, intermodulation distortion compensation being carried out to base band item and fundamental frequency item.

From formula (7), the intermodulation distortion that out of band signal causes is compensated.

But nonlinear distortion signal is still subject to the impact of third order intermodulation distortion, so Digital Signal Processing also comprises the third order intermodulation distortion compensation module of the compensation carrying out third order intermodulation distortion.This module respectively and side by side to inhibit the frequency spectrum of XMD to carry out filtering, by the third order intermodulation distorted signal of corresponding two two-tone signals respectively separately, suppresses separately third order intermodulation distortion process simultaneously.

Suppose that following three rank compensating signals are set up:

Wherein, represent low-pass filtering, λ ₁and λ ₂be three rank matching factors of two-way third order intermodulation distorted signal, be specifically expressed as:

${\mathrm{\λ}}_1=\frac{1}{OIP{3}_{\left(1\right)}\·R_{50}}---\left(10\right)$

${\mathrm{\λ}}_2=\frac{1}{OIP{3}_{\left(2\right)}\·R_{50}}---\left(11\right)$

Wherein, R ₅₀be the output impedance of the optical link comprising the equipment such as a PC, MZM1, the 2nd PC, MZM2, be generally 50 Ω, OIP3 ₍₁₎and OIP3 ₍₂₎the output three rank point of cut-off of each road signal, can by obtaining the detection fundamental frequency signal power P of each two-tone signal ₁and intermodulation signal power P ₃obtain, be specifically expressed as: $OIP3\≈\sqrt{\frac{P_1^3}{p_3}}.$

Based on above theory analysis, finally obtain linearizing two-way intermediate-freuqncy signal S _l1and S _l2:

$S_{L1}\≈\frac{S_{xmc}\left(t\right)}{S_{IMD1}\left(t\right)}\∝\left({\mathrm{\β\ρ}}_k\right)sin\left({\mathrm{\ω}}_{IF1}t\right),(k=1)---\left(12\right)$

$S_{L2}\≈\frac{S_{xmc}\left(t\right)}{S_{IMD2}\left(t\right)}\∝\left({\mathrm{\β\ρ}}_k\right)sin\left({\mathrm{\ω}}_{IF2}t\right),(k=2)---\left(13\right)$

To sum up, in the embodiment of the present invention, as shown in Figure 3, the third order intermodulation distortion compensation module realizing third order intermodulation distortion compensation comprises: the first bandpass filtering submodule and the second bandpass filtering submodule, for carrying out bandpass filtering treatment to the nonlinear distortion signal compensated through intermodulation distortion respectively, obtain two third order intermodulation distorted signals; First square of process submodule and second square of process submodule, for carrying out the process of squared value to two third order intermodulation distorted signals respectively; First low-pass filtering submodule and the second low-pass filtering submodule, for carrying out low-pass filtering treatment to two third order intermodulation distorted signals through square value process respectively; First third order intermodulation distortion compensation submodule and the second third order intermodulation distortion compensation submodule, for processing the third order intermodulation distorted signal after low-pass filtering respectively, obtain two three rank compensating signals; First signal output sub-module and secondary signal output sub-module, for respectively by two three rank compensating signals in conjunction with intermodulation distortion compensate after nonlinear distortion signal, obtain the linearizing signal of two-way and export.

The treatment system of this nonlinear properties that the embodiment of the present invention proposes, by extracting XMD and IMD3 compensated information from the nonlinear distortion signal received, digitally multiplying nonlinear distorted signal and compensated information, XMD and IMD3 distortion can be inhibited simultaneously, avoid the amount of calculation of traditional algorithm scheme complexity, also without the need to passing through the new nonlinear compensation path of constructed in hardware one, in addition, it also avoid the simultaneously match problem of distorted signal and compensating signal.

Below, carry out the checking of related experiment according to the treatment system of nonlinear properties as shown in Figure 2, the wavelength that LASER Light Source exports is 1550nm, power is the light carrier of 16dBm, the broadband rf signal that loads by MZM1 modulate.Broadband rf signal simulated by two two-tone signals, and its frequency is respectively 15GHz and 14.997GHz, 2.5GHz and 2.499GHz.MZM1 is offset to 120 °, and the MZM2 of cascade is offset to quadrature bias point, for carrying out the down-converted of nonlinear distortion signal.Two local oscillation signals that MZM2 loads are respectively 14.938GHz and 2.481GHz.Finally, the Data Acquisition Card utilizing ADlinkPCI-9820 model, acquisition rate to be 200MHz/s carries out data acquisition, carries out Digital Signal Processing through digital signal processor.

When the radio-frequency power of two two-tone signals inputted is respectively 4.5dBm and 5dBm, the suppression of comparison diagram 4 and Fig. 5, XMD is respectively 36.6dB and 23.8dB; The suppression of comparison diagram 6 and Fig. 7, IMD3 is respectively 25.8dB and 25.6dB.

Scan the radio-frequency power of two radiofrequency signals further respectively, after known XMD compensates, the dynamic range of analog optical link improves 27dB; After carrying out IMD3 compensation, corresponding analog optical link dynamic range improves 20dB.

Although execution mode disclosed in this invention is as above, the execution mode that described content just adopts for the ease of understanding the present invention, and be not used to limit the present invention.Technical staff in any the technical field of the invention; under the prerequisite not departing from spirit and scope disclosed in this invention; any amendment and change can be done what implement in form and in details; but scope of patent protection of the present invention, the scope that still must define with appending claims is as the criterion.

Claims (10)

1. a processing method for nonlinear distortion signal, is characterized in that, comprising:

Obtain nonlinear distortion signal, described nonlinear distortion signal is digital signal, through the modulation of two two-tone signals;

Obtain intermodulation distortion penalty coefficient, intermodulation distortion compensation is carried out to described nonlinear distortion signal;

The nonlinear distortion signal compensated through intermodulation distortion is separated, obtains two third order intermodulation distorted signals, the corresponding two-tone signal of each third order intermodulation distorted signal;

Obtain two three rank matching factors, respectively third order intermodulation distortion compensation is carried out to two third order intermodulation distorted signals, and the nonlinear distortion signal after compensating in conjunction with intermodulation distortion, obtain the linearizing signal of two-way.

2. method according to claim 1, is characterized in that, before acquisition nonlinear distortion signal, also comprises:

Obtain two local oscillation signals, down-converted is carried out to described nonlinear distortion signal, by described nonlinear distortion signal frequency conversion to its intermediate frequency or base band.

3. method according to claim 2, is characterized in that, described intermodulation distortion penalty coefficient depends on the working point utilizing two two-tone signals to modulate to obtain the Mach of nonlinear distortion signal to increase Dare modulator.

4. method according to claim 3, is characterized in that, obtains intermodulation distortion penalty coefficient, carries out intermodulation distortion compensation comprise described nonlinear distortion signal:

Bandpass filtering treatment and low-pass filtering treatment are carried out to described nonlinear distortion signal, obtains fundamental frequency item and the base band item of described nonlinear distortion signal respectively;

Obtain intermodulation distortion penalty coefficient;

Utilize small signal approximation, based on obtained intermodulation distortion penalty coefficient, intermodulation distortion compensation is carried out to described base band item and described fundamental frequency item.

5. method according to claim 1, it is characterized in that, obtain two three rank matching factors, respectively third order intermodulation distortion compensation is carried out to two third order intermodulation distorted signals, and the nonlinear distortion signal after compensating in conjunction with intermodulation distortion, obtain the linearizing signal of two-way and comprise:

Respectively the process of squared value is carried out to two third order intermodulation distorted signals;

Respectively low-pass filtering treatment is carried out to two third order intermodulation distorted signals through square value process;

Obtain two three rank matching factors, respectively the third order intermodulation distorted signal after low-pass filtering is processed, obtain two three rank compensating signals;

Nonlinear distortion signal after being compensated in conjunction with intermodulation distortion by two three rank compensating signals respectively, obtains the linearizing signal of two-way and exports.

6. a treatment system for nonlinear distortion signal, described nonlinear distortion signal increases Dare modulator by first Mach to produce, and it is characterized in that, described system comprises photodetector, data collecting card and digital signal processor,

Described photodetector is used for the nonlinear distortion signal for analog signal to be converted to digital signal, and described nonlinear distortion signal is the modulation of digital signal two two-tone signals;

Described data collecting card is for being retrieved as the nonlinear distortion signal of digital signal;

Described digital signal processor comprises: intermodulation distortion compensating module and third order intermodulation distortion compensation module,

Described intermodulation distortion compensating module, for obtaining intermodulation distortion penalty coefficient, carries out intermodulation distortion compensation to described nonlinear distortion signal;

Described third order intermodulation distortion compensation module is used for the nonlinear distortion signal compensated through intermodulation distortion to separate, and obtains two third order intermodulation distorted signals, the corresponding two-tone signal of each third order intermodulation distorted signal; Obtain two three rank matching factors, respectively third order intermodulation distortion compensation is carried out to two third order intermodulation distorted signals, and the nonlinear distortion signal after compensating in conjunction with intermodulation distortion, obtain the linearizing signal of two-way.

7. system according to claim 6, is characterized in that, also comprises second Mach and increases Dare modulator,

Described second Mach increasing Dare modulator for obtaining two local oscillation signals, utilizing two local oscillation signals to carry out down-converted to described nonlinear distortion signal, by described nonlinear distortion signal frequency conversion to its intermediate frequency or base band;

Described photodetector is used for being converted to digital signal by through down-converted and for the nonlinear distortion signal of analog signal.

8. system according to claim 7, is characterized in that, described intermodulation distortion penalty coefficient depends on the described first Mach of working point increasing Dare modulator utilizing two two-tone signals to modulate to obtain described nonlinear distortion signal.

9. system according to claim 8, is characterized in that, described intermodulation distortion compensating module comprises:

Bandpass filtering submodule, for carrying out bandpass filtering treatment to described nonlinear distortion signal, obtains the fundamental frequency item of described nonlinear distortion signal;

Low-pass filtering submodule, for carrying out low-pass filtering treatment to described nonlinear distortion signal, obtains the base band item of described nonlinear distortion;

Obtain submodule, for obtaining intermodulation distortion penalty coefficient;

Compensating submodule, for utilizing small signal approximation, based on obtained intermodulation distortion penalty coefficient, intermodulation distortion compensation being carried out to described base band item and described fundamental frequency item.

10. system according to claim 9, is characterized in that, described third order intermodulation distortion compensation module comprises:

First bandpass filtering submodule and the second bandpass filtering submodule, for carrying out bandpass filtering treatment to the nonlinear distortion signal compensated through intermodulation distortion respectively, obtain two third order intermodulation distorted signals;

First square of process submodule and second square of process submodule, for carrying out the process of squared value to two third order intermodulation distorted signals respectively;

First low-pass filtering submodule and the second low-pass filtering submodule, for carrying out low-pass filtering treatment to two third order intermodulation distorted signals through square value process respectively;

First third order intermodulation distortion compensation submodule and the second third order intermodulation distortion compensation submodule, for processing the third order intermodulation distorted signal after low-pass filtering respectively, obtain two three rank compensating signals;

First signal output sub-module and secondary signal output sub-module, for respectively by two three rank compensating signals in conjunction with intermodulation distortion compensate after nonlinear distortion signal, obtain the linearizing signal of two-way and export.