CN101146314A - A standing wave ration detection device and method for time division duplex communication system - Google Patents

Abstract

The invention relates to a detection method of standing-wave ratio of a time division duplex communication system, which comprises the following steps: a forward signal is sampled by switching a switch at a time interval of standing-wave ratio measurement; a reverse signal is sampled by switching the switch at the next time interval of standing-wave ratio measurement; the forward and the reverse signals is coupled and delivered to a digital-to-analog converter through a coupling passage, the delivered signal is sampled and quantized by using an AD sampler and processed by means of digital down-conversion to obtain a sampled data of baseband; a reflection coefficient |gamma_AD| is obtained by calculating, the transmission characteristic difference CF_R(Omega 0) between a forward detection channel and a reverse detection channel is obtained at the current frequency after table lookup process; and the standing-wave ratio VSWR is calculated based on the reflection coefficient |gamma_AD| and the transmission characteristic difference CF_R(Omega 0). Therefore, the invention realizes the multiplexing of a normal reception channel and the reverse and the forward standing-wave ratio channels, enables the normal reception channel to be used in standing-wave ratio detection, and ensures the equivalency of front/reverse power samplings by measuring the front and the reverse powers of the pilot frequency.

Description

A kind of standing wave ration detection device of tdd communication systems and method

Technical field

The present invention relates to time division duplex mobile communication system in the mobile communication technology field, in particular to a kind of standing-wave ratio detecting method and device of time division duplex mobile communication system.

Background technology

Base station VSWR (Voltage Standing Wave Ratio, standing-wave ratio) is an important parameter of radio frequency.Standing wave is not cause owing to the impedance in the delivering path matches, and when not matching appears in the delivering path middle impedance, understands some signal power and is reflected, and this reflected signal forms standing wave with the stack that transmits.Standing-wave ratio means that more greatly signal reflex is relatively more severe, that is to say that the matching effect on the delivering path is poor.And in an emission system, if standing-wave ratio big (normally because bad the causing of physical connection that a variety of causes causes), the then actual power of launching by antenna opening will descend, cause the covering of system to be shunk, usually the transmitting power that improves antenna opening needs the power amplifying device and the relevant complex technology of higher cost, and therefore good stationary wave characteristic is the effectively important assurance of work of system.If standing wave is excessive simultaneously, strong excessively reflected signal may cause the damage of system equipment, causes the decline of equipment dependability.For the covering that guarantees system with for the demand of equipment protection, be necessary the VSWR of system's transmission channel is detected, in time to pinpoint the problems, report and alarm worsens the problem of bringing so that system takes measures to correct or reduces standing wave.

Traditional standing-wave ratio detecting method all is to use a kind of directional coupler at the forward power amplifier delivery outlet of base station or antenna opening, obtains forward direction coupled signal and reverse coupled signal respectively.Re-use power detection device or power-sensing circuit and obtain forward direction coupled signal power and reverse coupled signal power.According to the standing-wave ratio of correlation computations acquisition institute test point, the dependent threshold according to default produces standing-wave ratio alarm again.Yet in the VSWR detection scheme in this correlation technique, the ability of its radio-frequency module depends on manufacturing information.Particularly: backward power only is used for VSWR to be calculated, and power detection adopts modulus conversion chip to realize that this has caused the higher shortcoming of this scheme cost.The VSWR of this technical scheme detects in addition needs higher power-sensing circuit of cost and the bigger radio frequency veneer of volume.And this technical scheme is subject to the precision of modulus conversion chip, causes accuracy of detection lower.

Patent 200610149605.2 provides a kind of standing-wave ratio detecting method, the feedback path of the transmitter by multiplexing tape base band predistortion function, by diverter switch transmission line is successively carried out forward power detection and backward power detection, to measure the preceding/backward power of transmission line, and utilize the gain of feedback path that preceding/backward power is adjusted, to obtain the preceding/backward power of antenna opening; Calculate standing-wave ratio VSWR then.But this method requirement equipment has feedback path, is only applicable to have the transmitter of base band predistortion function (feedback path is provided), and the scope of application is limited.Secondly, this method requires when standing-wave ratio detects, and requires real-time real-time gain according to temperature and frequency acquisition feedback path, has increased the complexity that standing-wave ratio is calculated.Once more, this method thinks that certainty of measurement is relevant in the precision of feedback path gain Vs temperature correction table, and the temperature of physical channel and frequency match obtain accurately that channel gain is the comparison difficulty, and error is inevitable.Once more, the feedback path temperature correction table that this method adopts requires the change in gain amount writing module memory of sampling different temperatures in the module production process, and this method workload is very huge, and error is higher.Cause follow-up standing-wave ratio accuracy of detection to descend.Once more, backward power detected before this method was switched selection by radio-frequency (RF) switch, make forward power detect and backward power to detect be not the signal of synchronization, owing to the frequent access of user in the real system with hang up and the influence of rapid power control, this method can be brought the error of measurement result.Only adopt repeatedly measurement on average to improve in this method, but can not effectively avoid the error of this measurement result.Once more, this method for solve forward power and detect and backward power to detect be not this shortcoming of signal of synchronization, adopted long-time average mode, the increase that brings computation complexity makes system's complexity that becomes.Once more, adopt complicated dB mode to represent that middle conversion process is brought the VSWR error of calculation in this method.

Therefore, people need a kind of new calculate more easy, precision is high, VSWR (standing-wave ratio) detection scheme cheaply, can solve the problem in the above-mentioned correlation technique.

Summary of the invention

The present invention aims to provide a kind of standing-wave ratio detecting method and device that is applicable to tdd communication systems, detects problem with the standing-wave ratio that solves in the above-mentioned correlation technique.Select diverse ways according to the difference of application scenarios and the resource requirement that realizes, can effectively reduce the influence of interference, can reduce the complexity of calculating simultaneously measuring.And realize normal receive path, oppositely and the standing-wave ratio channel multiplexing of forward direction unification, realizing using normal receive path to be used for standing-wave ratio detects, utilize the characteristics of pilot tone simultaneously, before the preceding backward power by measurement pilot frequency realizes/the equivalent homogeny of backward power sampling, have degree of precision.

The present invention includes the solution of following problem:

1. the homogeny of preceding reverse coupled signal sampling or equivalent homogeny

The present invention is based on forward direction should be identical or equivalent identical with the used signal of backward power detection.For the consideration of saving equipment cost and volume, requirement is finished forward direction and backward power detection with same circuit, carry out the switching of forward direction and reverse coupled signal by switch, because switching forward direction and reverse coupled signal is not the same signal of same time, so in order to guarantee that forward direction and backward power detect the equivalent homogeny of used signal, the pilot signal in the selection employing tdd communication systems or other have the signal execution standing-wave ratio detection that similar different time has the equal transmit power characteristic.For the TD-SCDMA system, its pilot signal be at pilot time slot (DwPTS time slot) independently with constant transmitting power emission, therefore adopt pilot signal to carry out standing-wave ratio and detect more satisfactory for this system.Therefore have preceding reverse signal that similar different time has a signal of equal transmit power characteristic by switch switch sampling pilot signal or other and carry out standing-wave ratio and detect, have the equivalent homogeny of preceding reverse signal measurement.

2. the method for measurement of standing-wave ratio

The following description of standing wave ratio measurement method:

According to common characteristics of signals, can suppose that the forward direction coupled signal of Coupling point place coupling is:

Wherein I (i) is that same phasor1, the Q (j) of signal is the orthogonal vector of signal, ω ₀Be carrier frequency;  (i) is current phase place,  ₀Be fixed phase.

Then the reverse coupled signal is:

$b=\underset{k=1}{\overset{K}{\mathrm{\Σ}}}{b}_k$ , k=1～K wherein, the reflected signal of expression difference.

A wherein _kBe the amplitude of reflected signal,  _kFixed phase for reflected signal.

Then:

Reflection coefficient

Then:

Voltage standing wave ratio

$\mathrm{\ρ}=\frac{1+\left|\mathrm{\Γ}\right|}{1-\left|\mathrm{\Γ}\right|}$

Wherein:

The mould of reflection coefficient

Preceding reverse signal after the coupling is down-converted to digital to analog converter (AD converter) by preceding reverse coupled passage, and AD sampling device will be sent the forward direction coupled signal that obtains the AD quantification after signal sampling quantizes here and be:

Wherein A is the amplitude of signal.

The reverse coupled signal is:

Wherein, Ae ^{J θ 0}Be the impulse response of coupling sense channel, C _{F_R}Be the transmission characteristic difference of different frequent points forward detection passage and inverse detection passage, this value does not vary with temperature, and only depends on used frequency.

For AD sampling device, there is linear relationship between AD sampled value and the signal voltage, available following formulate:

Voltage V=KA

Wherein: V is the voltage of AD input signal, and A is a sampled value, and K is a constant.

Will seek out reflection coefficient this moment | Γ _{_ AD}|, then at first the sampling of the baseband digital signal after the digital down-frequency conversion is obtained base band data and is:

The baseband sampling a that transmits _{_ BB}=Ia _{_ BB}+ j*Qa _{_ BB}

Wherein:

The I roadbed band sampling that transmits

The Q roadbed band sampling that transmits

The baseband sampling b of reflected signal _{_ BB}=Ib _{_ BB}+ j*Qb _{_ BB}

Wherein:

The I roadbed band sampling of reflected signal

The Q roadbed band sampling of reflected signal

From baseband signal, obtain reflection coefficient | Γ _{_ AD}| the comparison effective method have following three kinds:

Method one:

Extract base band forward direction and reverse signal power indication (RSSI) from baseband digital signal, the power of signal is meant average power, and the peak-to-average force ratio of signal of communication is bigger usually, should carry out the root mean square computing to the signal of sampling.Detection to signal strength signal intensity RSSI can obtain by following formula:

The signal power indication $\mathrm{RSSI}=\frac{1}{N}\·\underset{n=1}{\overset{N}{\mathrm{\Σ}}}({\left|I\left(n\right)\right|}^2+{\left|Q\left(n\right)\right|}^2)$ (N counts for detecting)

Then:

Reflection coefficient $\left|{\mathrm{\Γ}}_{\_\mathrm{AD}}\right|=\sqrt{\frac{p_{b\_\mathrm{BB}}}{p_{a\_\mathrm{BB}}}}=C_{F\_R^{{\mathrm{\α}}_b}}$

Wherein:

The signal power that transmits is

$P_{a\_\mathrm{BB}}=\frac{1}{N}\·\underset{n=1}{\overset{N}{\mathrm{\Σ}}}({\left|{\mathrm{Ia}}_{\_\mathrm{BB}}\left(n\right)\right|}^2+{\left|{\mathrm{Qa}}_{\_\mathrm{BB}}\left(n\right)\right|}^2)=\frac{1}{N}\·\underset{n=1}{\overset{N}{\mathrm{\Σ}}}\left(A^2(I{\left(i\right)}^2+Q{\left(i\right)}^2)\right)$

The signal power of reflected signal is

$P_{b\_\mathrm{BB}}=\frac{1}{N}\·\underset{n=1}{\overset{N}{\mathrm{\Σ}}}({\left|{\mathrm{Ib}}_{\_\mathrm{BB}}\left(n\right)\right|}^2+{\left|{\mathrm{Qb}}_{\_\mathrm{BB}}\left(n\right)\right|}^2)=\frac{1}{N}\·\underset{n=1}{\overset{N}{\mathrm{\Σ}}}{\left({\mathrm{AC}}_{F\_R^{{\mathrm{\α}}_b}}\right)}^2(I{\left(i\right)}^2+Q{\left(i\right)}^2)$

Method two:

Obtain the auto-correlation function of forward direction coupled signal and the cross-correlation function of preceding reverse coupled signal respectively, obtain by following formula:

The auto-correlation function of forward direction coupled signal is

$\mathrm{Cov}(a_{\_\mathrm{BB}},a_{\_\mathrm{BB}})=\frac{1}{N}\·\underset{n=1}{\overset{N}{\mathrm{\Σ}}}(a_{\_\mathrm{BB}}\left(n\right)*\mathrm{conj}\left(a_{\_\mathrm{BB}}\left(n\right)\right))=\frac{A^2}{N}\·\underset{i=1}{\overset{N}{\mathrm{\Σ}}}(I{\left(i\right)}^2+Q{\left(i\right)}^2)$

The cross-correlation function of preceding reverse coupled signal is

Correlation length is the sequence length of target detection signal, and sliding window calculates in sampling window, tries to achieve the maximum of correlation, as the benchmark of subsequent calculations.

Then:

Reflection coefficient

Method three:

Adopt the method for FFT to estimate:

Reflection coefficient $\left|{\mathrm{\Γ}}_{\_\mathrm{AD}}\right|=\mathrm{IFFT}\left[\frac{\mathrm{FFT}\left(b_{\_\mathrm{BB}}\right)}{\mathrm{FFT}\left(a_{\_\mathrm{BB}}\right)}\right]=C_{F\_R^{{\mathrm{\α}}_b}}$

Calculate according to above | Γ _{_ AD}| and obtain C by tabling look-up _{F_R}, and then obtain the standing-wave ratio of coupling port:

Voltage standing wave ratio $\mathrm{VSWR}=\frac{C_{F\_R}+\left|{\mathrm{\Γ}}_{\_\mathrm{AD}}\right|}{C_{F\_R}-\left|{\mathrm{\Γ}}_{\_\mathrm{AD}}\right|.}$

The detection method of standing-wave ratio provides three kinds of methods, can select diverse ways according to the different of application scenarios and the resource requirement that realizes, can effectively reduce the influence of interference to measuring, and can reduce the complexity of calculating simultaneously.

Specifically, the invention discloses a kind of standing-wave ratio detecting method, may further comprise the steps:

Step S1 at SWR measurement time slot (as descending pilot transmission time slot), by diverter switch, carries out the forward signal sampling of SWR measurement signal earlier; At next SWR measurement time slot (descending pilot frequency transmission time slot),, carry out the reverse signal sampling of SWR measurement signal by diverter switch.After the forward direction of coupling and reverse signal sent into digital to analog converter after by coupling channel, will send signal sampling here by AD sampling device and quantize the sampling that obtains base band is handled in the back by Digital Down Convert data.

The baseband sampling value of forward direction coupled signal is designated as: a _{_ BB_1}, a _{BB 2}... .., a _{_ BBNN}

The baseband sampling value of reverse coupled signal is designated as: b _{_ BB_1}, b _{_ BB_2}... .., b _{_ BB_N}

According to the described standing wave ration detection device schematic diagram of Fig. 4 as can be seen, at synchronization, the transmission characteristic difference of forward detection passage and inverse detection passage only depends on the transmission characteristic of directional coupler, and directional coupler belongs to passive device, in the operating temperature range of equipment, its transmission characteristic varies with temperature constant substantially, so the transmission characteristic difference of forward detection passage and inverse detection passage (being relative amplitude and phase relation) does not vary with temperature and changes.

The transmission characteristic of supposing the forward detection passage is H _F(ω), then the transmission characteristic of inverse detection passage is H _R(ω), H _R(ω)=H _F(ω) * C _FR(ω).C wherein _{F_R}(ω)=A (ω) e ^{J θ (ω)}, being the transmission characteristic difference of different frequent points forward detection passage and inverse detection passage, this value does not vary with temperature, and only depends on used frequency.

Because there is certain discreteness in analog channel, for the precision that guarantees to detect, reduce the workload of debugging, will in the module production process, obtain C by calibration measurement _{F_R}, being stored in the module by the form of form, form is as follows:

Calibration frequency f	f 1	f 2	f 3	…	f N-1	f N
							Transmission characteristic difference C F_R(f)	C F_R	C F_R	C F_R	…	C F_R(	C F_R(

The selection of calibration frequency can be chosen abundant point according to the demand of physical channel, also several frequencies of the selection that can disperse, the transmission characteristic difference C of other frequencies _{F_R}(ω) obtain by the mode that fits.

Step S2 according to previously described three kinds of standing wave ratio measurement methods, selects a kind of effective method of measurement, tries to achieve reflection coefficient | Γ _{_ AD}|:

Reflection coefficient | Γ _{_ AD}|=C _{F_R}α _b

Utilize the method for fitting to draw the forward detection passage of current frequency and the transmission characteristic difference C of inverse detection passage by the back of tabling look-up _{F_R}(ω ₀).

Step S3, according to reflection coefficient | Γ _{_ AD}| and transmission characteristic difference C _{F_R}(ω ₀) obtain standing-wave ratio VSWR. by following formula

Voltage standing wave ratio $\mathrm{VSWR}=\frac{C_{F\_R}\left({\mathrm{\ω}}_0\right)+\left|{\mathrm{\Γ}}_{\_\mathrm{AD}}\right|}{C_{F\_R}\left({\mathrm{\ω}}_0\right)-\left|{\mathrm{\Γ}}_{\_\mathrm{AD}}\right|.}$

In above-mentioned standing-wave ratio detecting method, steps A may further comprise the steps: at predetermined SWR measurement time slot, carry out the coupling of forward/reverse signal earlier, use diverter switch to switch afterwards, at the identical SWR measurement time slot of equivalence, carry out the reverse/forward power coupling; Forward direction coupled signal that obtains respectively and the sampled value of reverse coupled signal in cycle a period of time are respectively

The baseband sampling value of forward direction coupled signal: a _{_ BB_1}, a _{_ BB_2}... .., a _{_ BB_N}

The baseband sampling value of reverse coupled signal: b _{_ BB_1}, b _{_ BB_2}... .., b _{_ BB_N}

In above-mentioned standing-wave ratio detecting method, carry out the sampling of forward/reverse coupled signal, or the gap periods of carrying out reverse/forward direction coupled signal sampling depends on the frame period of the system that is adopted, be equivalent same signal between the cycle, the time cycle of each sampled signal is to begin to finish (consideration propagation delay time) to emission from the emission of SWR measurement time slot.

In above-mentioned standing-wave ratio detecting method, step S2 may further comprise the steps:

According to current operating frequency, before the inquiry/the transmission characteristic difference correction table of inverse detection passage, according to following formula:

Transmission characteristic difference $C_{F\_R}\left(f_0\right)=C_{F\_R}\left(f_m\right)+\frac{C_{F\_R}\left(f_{m+1}\right)-C_{F\_R}\left(f_m\right)}{f_{m+1}-f_m}\·(f_0-f_m),$ F wherein _m≤ f ₀≤ f _M+1

Its amplitude is fitted, obtain the transmission characteristic difference C of the preceding/inverse detection passage under the current frequency _{F_R}(ω ₀)

In above-mentioned standing-wave ratio detecting method, step S3 comprises that the following formula of utilization uses transmission characteristic difference C _{F_R}(ω) and reflection coefficient | Γ _{_ AD}| calculating voltage standing-wave ratio VSWR:

$\mathrm{VSWR}=\frac{C_{F\_R}\left({\mathrm{\ω}}_0\right)+\left|{\mathrm{\Γ}}_{\_\mathrm{AD}}\right|}{C_{F\_R}\left({\mathrm{\ω}}_0\right)-\left|{\mathrm{\Γ}}_{\_\mathrm{AD}}\right|.}$

According to a further aspect in the invention, the invention provides a kind of standing wave ration detection device, comprise: preceding/reverse coupled signal sampling module, be used for the preceding/reverse signal of predetermined SWR measurement time slot being sampled by diverter switch, Digital Down Convert is adopted in the back, and the sampled signal of expecting is down-converted to base band; Measurement of reflection-factor module is used for preceding/reverse baseband signal of obtaining according to sampling, calculates according to measurement of reflection-factor method, obtains | г _{_ AD}|; Before/the backward channel adjusting module, be used for according to current operating frequency, before the inquiry/the transmission characteristic difference correction table of inverse detection passage, according to following formula:

Transmission characteristic difference $C_{F\_R}\left(f_0\right)=C_{F\_R}\left(f_m\right)+\frac{C_{F\_R}\left(f_{m+1}\right)-C_{F\_R}\left(f_m\right)}{f_{m+1}-f_m}\·(f_0-f_m),$ F wherein _m≤ f ₀≤ f _M+1

Its amplitude is fitted, obtain the transmission characteristic difference C of the preceding/inverse detection passage under the current frequency _{F_R}(ω ₀)

And standing-wave ratio calculating module, be used to utilize transmission characteristic difference C _{F_R}(ω ₀) and reflection coefficient | Γ _{_ AD}| calculate standing-wave ratio VSWR.

In above-mentioned standing wave ration detection device, preceding/reverse coupled signal sampling module comprises: preceding/the reverse signal sampling module, be used at predetermined SWR measurement time slot, carry out the preceding/reverse signal sampling of forward/reverse earlier, use diverter switch to switch afterwards, at next SWR measurement time slot, carry out oppositely/the forward signal sampling; And Digital Down Converter Module, be used for reverse/forward signal, by obtaining the preceding/reverse sampled signal of base band after Digital Down Convert and the filtering according to the AD sampling.

In above-mentioned standing wave ration detection device, carry out the sampling of forward/reverse coupled signal, or the gap periods of carrying out reverse/forward direction coupled signal sampling depends on the frame period of the system that is adopted, be equivalent same signal between the cycle, the time cycle of each sampled signal is to begin to finish (consideration propagation delay time) to emission from the emission of SWR measurement time slot.

In above-mentioned standing wave ration detection device, measurement of reflection-factor module: be used for preceding/reverse baseband sampling signal of obtaining according to the Digital Down Convert of sampling back, calculate, obtain reflection coefficient according to measurement of reflection-factor method | г _{_ AD}|;

In above-mentioned standing wave ration detection device, preceding/the backward channel adjusting module: as to be used for according to current operating frequency, to inquire about and fit the transmission characteristic difference of preceding/inverse detection passage, obtain the transmission characteristic difference C of the preceding/inverse detection passage under the current frequency _{F_R}(ω ₀).

In above-mentioned standing wave ration detection device, standing-wave ratio is calculated module and is used to utilize following formula to use transmission characteristic difference C _{F_R}(ω ₀) and reflection coefficient | Γ _{_ AD}| calculating voltage standing-wave ratio VSWR: voltage standing wave ratio $\mathrm{VSWR}=\frac{C_{F\_R}\left({\mathrm{\ω}}_0\right)+\left|{\mathrm{\Γ}}_{\_\mathrm{AD}}\right|}{C_{F\_R}\left({\mathrm{\ω}}_0\right)-\left|{\mathrm{\Γ}}_{\_\mathrm{AD}}\right|.}$

The present invention passes through Digital Signal Processing, the reflection coefficient of calculating in the base band of coupling channel as can be seen from the above description | г _{_ AD}|, and then, extrapolate the standing-wave ratio of coupling port according to the transmission characteristic difference of the preceding/inverse detection passage of coupling channel.

Specifically, the invention discloses a kind of standing wave ration detection device, specifically comprise:

The Digital Up Convert unit is finished the shaping filter of baseband signal and is modulated to desired intermediate frequency;

D/A conversion unit, finishing digital signal transition is analog if signal;

The filtering to the emission medium-frequency signal of not expecting is finished in the intermediate frequency filtering unit;

The intermediate frequency amplifying unit is finished the amplification with intermediate-freuqncy signal;

The radio frequency that intermediate-freuqncy signal is transformed to expectation is finished in simulation up-conversion unit;

The filtering to the radio frequency transmissions of not expecting is finished in the rf filtering unit;

The radio frequency amplifying unit is finished the amplification of radiofrequency signal;

The duplex that transmits and receives is finished in the circulator unit;

The directional couple to preceding reverse signal is finished in the directional coupler unit;

The filtering of radio-frequency receiving-transmitting signal is finished in the front-end filtering unit;

Before/the reverser switch unit, the switch of finishing preceding/inverse detection switches;

Digital filtering and shaping filter to the digital signal that receives are finished in the Digital Down Convert unit;

The LNA big unit that receives, the low noise of finishing received signal amplifies;

Received RF filtering unit finishes receiving the filtering of the radiofrequency signal of not expecting;

Reception/sense switch switch unit, the switch of finishing reception/detection switches;

The analog down unit is finished the radiofrequency signal that will receive and is transformed to desired intermediate frequency;

Local oscillator power splitter unit is finished local oscillation signal merit branch is used to transmit and receive frequency conversion;

The generation of expectation local oscillation signal is finished in the local oscillator unit;

Receive the intermediate frequency filtering unit, finish the not filtering of desired intermediate frequency received signal;

Receive the intermediate frequency amplifying unit, finish amplification the intermediate-freuqncy signal that receives;

AD conversion unit is finished the analog-to-digital conversion of receiving intermediate frequency signal;

Standing-wave ratio is calculated the unit, finishes the standing-wave ratio that the digital signal that digital down-converter unit is obtained calculates system;

Radio frequency opens the light and the controlling of sampling unit, finishes switching sequence control LNA big unit and reception/sense switch switch unit, and the sampling of control AD conversion unit.

The SWR measurement apparatus and method that the present invention proposes are applicable to that TDD radio communication system has realized following technique effect: the present invention proposes a mode by the employing radio-frequency (RF) switch and realize normal receive path, standing-wave ratio channel multiplexing reverse and forward direction is unified, realizing using normal receive path to be used for standing-wave ratio detects, utilize the characteristics of pilot tone simultaneously, realize the equivalent homogeny of preceding/backward power sampling by the preceding backward power of measurement pilot frequency, has degree of precision, can make simultaneously and need not independently preceding/inverse detection coupling circuit on the veneer, cost, the veneer area all will significantly reduce, and reducing to reduce with cost for the radio-frequency module volume has important meaning.

Description of drawings

Accompanying drawing is used to provide further understanding of the present invention, and constitutes the part of specification, is used from explanation the present invention with embodiments of the invention one, is not construed as limiting the invention.In the accompanying drawings:

Fig. 1 is the flow chart that illustrates according to standing-wave ratio detecting method of the present invention;

Fig. 2 is the block diagram that illustrates according to standing wave ration detection device of the present invention;

Fig. 3 is the flow chart that illustrates according to the standing-wave ratio detecting method of the embodiment of the invention; And

Fig. 4 illustrates according to standing-wave ratio sense switch control timing figure of the present invention;

Fig. 5 is the principle schematic that illustrates according to standing-wave ratio detection scheme of the present invention.

Embodiment

Specifically describe the preferred embodiments of the present invention hereinafter with reference to accompanying drawing, wherein, accompanying drawing constitutes the application's a part, and is used from explaination principle of the present invention with embodiments of the invention one.

For the ease of understanding, will adopting in the third generation mobile typically below, time division duplex communication system TD-SCDMA system is that example is explained principle of the present invention.

The present invention puts forward a kind of standing-wave ratio detecting method and device.

Fig. 1 illustrates according to standing-wave ratio detecting method of the present invention, and it may further comprise the steps:

Step S1 at SWR measurement time slot (as descending pilot transmission time slot), by diverter switch (switch control time sequence during SWR measurement as shown in Figure 4), carries out the forward signal sampling of SWR measurement signal earlier; At next SWR measurement time slot (descending pilot frequency transmission time slot),, carry out the reverse signal sampling of SWR measurement signal by diverter switch.After the forward direction of coupling and reverse signal sent into digital to analog converter after by coupling channel, will send signal sampling here by AD sampling device and quantize the sampling that obtains base band is handled in the back by Digital Down Convert data.

The baseband sampling value of forward direction coupled signal is designated as: a _{_ BB_1}, a _{_ BB_2}... .., a _{_ BB_N}

The baseband sampling value of reverse coupled signal is designated as: b _{_ BB_1}, b _{_ BB_2}... .., b _{_ BB_N}And

Step S2 according to previously described three kinds of standing wave ratio measurement methods, selects a kind of effective method of measurement, tries to achieve reflection coefficient | г _{_ AD}|, the back utilization fits the forward detection passage of the current frequency of method and the transmission characteristic difference C of inverse detection passage by tabling look-up _{F_R}(ω ₀); And

Step S3, according to reflection coefficient | Γ _{_ AD}| and transmission characteristic difference C _{F_R}(ω ₀) calculate standing-wave ratio VSWR.

The present invention passes through Digital Signal Processing, the reflection coefficient of calculating in the base band of coupling channel as can be seen from the above description | г _{_ AD}|, and then, extrapolate the standing-wave ratio of coupling port according to the transmission characteristic difference of the preceding/inverse detection passage of coupling channel.

Step S1 may further comprise the steps: at SWR measurement time slot (as descending pilot transmission time slot), by diverter switch, carry out the forward signal sampling of SWR measurement signal earlier; At next SWR measurement time slot (descending pilot frequency transmission time slot),, carry out the reverse signal sampling of SWR measurement signal by diverter switch.After the forward direction of coupling and reverse signal sent into digital to analog converter after by coupling channel, will send signal sampling here by AD sampling device and quantize the sampling that obtains base band is handled in the back by Digital Down Convert data.The baseband sampling value of forward direction coupled signal is designated as: a _{_ BB_1}, a _{_ BB_2}... .., a _{_ BB_N}The baseband sampling value of reverse coupled signal is designated as: b _{_ BB_1}, b _{B_BB_2}... .., b _{_ BB_N}Obviously it is apparent to those skilled in the art that carrying out the forward signal sampling earlier carries out the reverse signal sampling again, perhaps carry out the reverse signal sampling earlier and carry out the forward signal sampling again that the effect that is reached is the same.

Suppose that pilot frequency sequence is m=( m ₁, m ₂..., m ₆₄), the pilot frequency sequence that forward power detects coupling is $\underset{\‾}{a_{\_\mathrm{BB}}}=\left(\underset{\‾}{a_{\_\mathrm{BB}\_1},a_{\_\mathrm{BB}\_2},\·\·\·,}\underset{\‾}{a_{\_\mathrm{BB}\_N}}\right),$ The pilot frequency sequence that backward power detects coupling is $\underset{\‾}{b_{\_\mathrm{BB}}}=(\underset{\‾}{b_{\_\mathrm{BB}\_1}},\underset{\‾}{b_{\_\mathrm{BB}\_2}},\·\·\·,\underset{\‾}{b_{\_\mathrm{BB}\_N}});$ Consider the time-delay of passage and the influences such as time delay expansion that the unmatched reflection of multiple spot brings, need be according to channels designs and the behaviour in service and the computational methods design sample window of reality.If the standing wave measurement method is for by power detection (method 1) and since pilot signal launch time internal power constant, then can pass through sample offset, select suitable sample window, assurance

With

Signal all is included in the pilot signal, and can guarantee certain computational accuracy, reduces the interference of external disturbance to result of calculation.

If the standing wave measurement method is for passing through detection method 2 or 3, these the two kinds of methods all reasonable opposing external interference of energy can reduce false-alarm largely to the influence of result of calculation, because these two kinds of algorithms require related operations, need to guarantee by suitable selection sample window

With

In all comprise pilot frequency sequence.

From above description, the present invention realizes normal receive path, oppositely and the standing-wave ratio channel multiplexing of forward direction unification by the mode that adopts radio-frequency (RF) switch as can be seen, realizing using normal receive path to be used for standing-wave ratio detects, thereby provide with low cost, a simple VSWR detection method of circuit, before veneer just need not independently like this/and the inverse detection coupling circuit, cost, veneer area all will significantly reduce.

Step S2 can may further comprise the steps:

According to previously described three kinds of standing wave ratio measurement methods, select a kind of effective method of measurement, try to achieve reflection coefficient | Γ _{_ AD}|.According to current operating frequency, inquiry forward direction and backward channel gain difference table utilize the method for fitting to obtain the forward detection passage of current frequency and the transmission characteristic difference C of inverse detection passage _{F_R}(6 ω ₀)

As can be seen from the above description, in the present invention program's standing-wave ratio detects, insensitive to variation of temperature.Only depend on the transmission characteristic difference C that calibration obtains _{F_R}Precision, this precision is high more, certainty of measurement is just high more.

Step S3 comprises according to reflection coefficient | Γ _{_ AD}| and transmission characteristic difference C _{F_R}(ω ₀) obtain standing-wave ratio VSWR by following formula:

$\mathrm{VSWR}=\frac{C_{F\_R}\left({\mathrm{\ω}}_0\right)+\left|{\mathrm{\Γ}}_{\_\mathrm{AD}}\right|}{C_{F\_R}\left({\mathrm{\ω}}_0\right)-\left|{\mathrm{\Γ}}_{\_\mathrm{AD}}\right|}$

Fig. 2 is the block diagram that illustrates according to standing wave ration detection device of the present invention, comprising:

Before/reverse coupled signal sampling module 21, be used for the preceding/reverse signal of predetermined SWR measurement time slot being sampled by diverter switch, Digital Down Convert is adopted in the back, and the sampled signal of expecting is down-converted to base band;

Measurement of reflection-factor module 22 is used for preceding/reverse baseband signal of obtaining according to sampling, calculates according to measurement of reflection-factor method, obtains reflection coefficient | Γ _{_ AD}|;

Before/backward channel adjusting module 23, be used for according to current operating frequency, inquire about and fit the transmission characteristic difference of preceding/inverse detection passage, obtain the transmission characteristic difference C of the preceding/inverse detection passage under the current frequency _{F_R}(ω ₀);

And standing-wave ratio calculating module 24, be used to utilize transmission characteristic difference C _{F_R}(ω ₀) and reflection coefficient | Γ _{_ AD}| calculate standing-wave ratio VSWR.

Preceding/reverse coupled signal sampling module 21 can comprise: preceding/the reverse signal sampling module, be used at predetermined SWR measurement time slot, carry out the preceding/reverse signal sampling of forward/reverse earlier, use diverter switch to switch afterwards, at next SWR measurement time slot, carry out oppositely/the forward signal sampling; And Digital Down Converter Module, be used for reverse/forward signal, by obtaining the preceding/reverse sampled signal of base band after Digital Down Convert and the filtering according to the AD sampling.

In above-mentioned standing wave ration detection device, carry out the sampling of forward/reverse coupled signal, or the gap periods of carrying out reverse/forward direction coupled signal sampling depends on the frame period of the system that is adopted, be equivalent same signal between the cycle, the time cycle of each sampled signal is to begin to finish (consideration propagation delay time) to emission from the emission of SWR measurement time slot.

Optionally, carry out forward/reverse signal coupling sampling, or carry out oppositely/switching cycle of forward direction coupling sampling is the multiple of 5ms or 5ms.

Measurement of reflection-factor module 22: be used for preceding/reverse baseband sampling signal of obtaining according to the Digital Down Convert of sampling back, calculate, obtain reflection coefficient according to measurement of reflection-factor method | г _{_ AD}|;

Before/backward channel adjusting module 23: be used for according to current operating frequency, inquire about and fit the transmission characteristic difference of preceding/inverse detection passage, obtain the transmission characteristic difference C of the preceding/inverse detection passage under the current frequency _{F_R}(ω ₀).

Standing-wave ratio is calculated module 24, is used to utilize following formula to use transmission characteristic difference C _{F_R}(ω ₀) and reflection coefficient | г _{_ AD}| calculate VSWR:

$\mathrm{VSWR}=\frac{C_{F\_R}\left({\mathrm{\ω}}_0\right)+\left|{\mathrm{\Γ}}_{\_\mathrm{AD}}\right|}{C_{F\_R}\left({\mathrm{\ω}}_0\right)-\left|{\mathrm{\Γ}}_{\_\mathrm{AD}}\right|.}$

Wherein, in the operation that above-mentioned standing-wave ratio detects, the present invention passes through Digital Signal Processing, the reflection coefficient of calculating in the base band of coupling channel as can be seen | Γ _{_ AD}|, and then, extrapolate the standing-wave ratio of coupling port according to the transmission characteristic difference of the preceding/inverse detection passage of coupling channel.

Here define transmission characteristic difference C _{F_R}(ω)=A (ω) e ^{J θ (ω}), being the transmission characteristic difference of different frequent points forward detection passage and inverse detection passage, this value does not vary with temperature, and only depends on used frequency.The transmission characteristic of wherein supposing the forward detection passage is H _F(ω), then the transmission characteristic of inverse detection passage is H _R(ω), H _R(ω)=H _F(ω) * C _{F_R}(ω).Because there is certain discreteness in analog channel, for the precision that guarantees to detect, reduce the workload of debugging, will in the module production process, obtain transmission characteristic difference C by calibration measurement _{F_R}, being stored in the module by the form of form, form is as follows:

Calibration frequency f	f 1	f 2	f 3	…	f N-1	f N
							Transmission characteristic difference C F_R(f)	C F_R	C F_R	C F_R	…	C F_Ro	C F_R(

The selection of calibration frequency can be chosen abundant point according to the demand of physical channel, also several frequencies of the selection that can disperse, the transmission characteristic difference C of other frequencies _{F_R}(ω) obtain by the mode that fits.

When carrying out standing-wave ratio VSWR measurement, need measure forward direction coupled signal and reverse coupled signal simultaneously, particularly, when carrying out the reverse coupled signal sampling, the switching mode switching need switch on the reverse coupled port of directional coupler.When carrying out preceding, reverse coupled signal sampling during standing-wave ratio VSWR measures, the simulation process passage of front end all is shared, only the coupler difference.This standing-wave ratio VSWR measures reflection be all later impedances of coupling test point do not match the reflected signal that causes stack and; because any bigger standing wave behind the power amplifier all brings deterioration to equipment and systemic-function; to be placed on behind the power amplifier be proper so standing wave detected; but this method is not got rid of the user and is placed on other links for certain purpose detects standing wave; but all can think the conspicuous application of the present invention, should belong to protection range of the present invention.

Fig. 3 is the flow chart that illustrates according to the standing-wave ratio detecting method of the embodiment of the invention, and it may further comprise the steps:

S301 waits for that the SWR measurement cycle arrives the startup SWR measurement;

S302, before calculating according to current test frequency/reverse coupled channel transfer characteristic is poor;

According to current operating frequency, before the inquiry/the transmission characteristic difference correction table of inverse detection passage, according to following formula:

Transmission characteristic difference $C_{F\_R}\left(f_0\right)=C_{F\_R}\left(f_m\right)+\frac{C_{F\_R}\left(f_{m+1}\right)-C_{F\_R}\left(f_m\right)}{f_{m+1}-f_m}\·(f_0-f_m),$ F wherein _m≤ f ₀≤ f _M+1

Its amplitude is fitted, obtain the transmission characteristic difference C of the preceding/inverse detection passage under the current frequency _{F_R}(ω ₀)

S303, standing-wave ratio VSWR measures time slot arrival by the time, and control radio frequency diverter switch places forward signal to detect;

S304 starts base band and receives data acquisition, gathers the forward direction coupling sampled signal that AD receives;

S305 carries out the base band data that Digital Down Convert obtains this forward direction coupling sampled signal;

The baseband sampling value of forward direction coupled signal is designated as: a _{_ BB_1}, a _{_ BB_2}... .., a _{_ BB_N}

S306 treats that VSWR measures time slot and finishes, and control radio frequency diverter switch places normal accepting state;

S307 waits for that the VSWR of next frame measures time slot arrival, and the control radio-frequency (RF) switch places the inverse detection state;

S308 starts base band and receives data acquisition, gathers the reverse coupled sampled signal that AD receives;

S309 carries out the base band data that Digital Down Convert obtains this reverse coupled sampled signal;

The baseband sampling value of reverse coupled signal is designated as: b _{_ BB_1}, b _{_ BB_2}... .., b _{_ BB_N}

S310 obtains current reflection coefficient according to reflection coefficient calculating method;

S311 calculates standing-wave ratio according to current reflection coefficient and preceding/reverse coupled channel transfer characteristic difference;

$\mathrm{VSWR}=\frac{C_{F\_R}\left({\mathrm{\ω}}_0\right)+\left|{\mathrm{\Γ}}_{\_\mathrm{AD}}\right|}{C_{F\_R}\left({\mathrm{\ω}}_0\right)-\left|{\mathrm{\Γ}}_{\_\mathrm{AD}}\right|}$

S312 according to the standing-wave ratio thresholding judges whether exceed the standing-wave ratio thresholding.

When the next SWR measurement cycle arrives, repeat above step again.

The present invention passes through Digital Signal Processing, the reflection coefficient of calculating in the base band of coupling channel as can be seen from the above description | г _{_ AD}|, and then, extrapolate the standing-wave ratio of coupling port according to the transmission characteristic difference of the preceding/inverse detection passage of coupling channel.

Further, the present invention realizes normal receive path, oppositely and the standing-wave ratio channel multiplexing of forward direction unification by the mode that adopts radio-frequency (RF) switch, realizing using normal receive path to be used for standing-wave ratio detects, thereby provide with low cost, a simple VSWR detection method of circuit, before veneer just need not independently like this/and the inverse detection coupling circuit, cost, veneer area all will significantly reduce.

Further, have than higher precision in standing-wave ratio detection of the present invention, precision and current working temperature are irrelevant, the precision that only depends on the transmission characteristic difference that digital processing and preceding/inverse detection passage are arranged, and these two amounts can both be accomplished higher precision usually, and therefore SWR measurement precision of the present invention is higher.

Fig. 4 illustrates according to standing-wave ratio sense switch control timing figure of the present invention; Frame sequential with TD-SCDMA is reference, explanation will receive at the transmission time slot of system/and sense switch places detected state, before in two continuous frames, disposing respectively simultaneously/inverse detection switch configuration-system detection forward direction and backward power, because the basic while of preceding/inverse detection, guaranteed the simultaneity that standing-wave ratio detects.

Fig. 5 shows a kind of schematic diagram example of standing wave ration detection device of the present invention.Be divided into as the lower part:

Radiating portion: 5001 are the Digital Up Convert unit, finish the shaping filter of baseband signal and are modulated to desired intermediate frequency.5002 is D/A conversion unit, finishing digital signal transition is analog if signal, and 5003 is the intermediate frequency filtering unit, finishes the filtering to the emission medium-frequency signal of not expecting, 5004 is the intermediate frequency amplifying unit, finish the amplification with intermediate-freuqncy signal, 5005 for simulation up-conversion unit, finishes the radio frequency that intermediate-freuqncy signal is transformed to expectation, 5006 is the rf filtering unit, finish the filtering to the radio frequency transmissions of not expecting, 5007 is the radio frequency amplifying unit, finishes the amplification of radiofrequency signal.

The front end conversion portion: 5008 is the circulator unit, finishes the duplex that transmits and receives, and 5009 is the directional coupler unit, finishes the directional couple to preceding reverse signal; 5010 is the front-end filtering unit, finishes the filtering of radio-frequency receiving-transmitting signal, and 5011 is preceding/reverser switch unit, and the switch of finishing preceding/inverse detection switches,

Receiving unit: 5012 LNA big units for reception, the low noise of finishing received signal amplifies, 5013 is received RF filtering unit, finish receiving the filtering of the radiofrequency signal of not expecting, 5014 are reception/sense switch switch unit, the switch of finishing reception/detection switches, and 5015 is the analog down unit, finishes the radiofrequency signal that will receive and transforms to desired intermediate frequency.

5016 is local oscillator power splitter unit, finish local oscillation signal merit branch is used to transmit and receive frequency conversion, 5017 is the local oscillator unit, finish the generation of expectation local oscillation signal, 5018 for receiving the intermediate frequency filtering unit, finish the not filtering of desired intermediate frequency received signal, 5019 for receiving the intermediate frequency amplifying unit, finish amplification to the intermediate-freuqncy signal that receives, 5020 is AD conversion unit, finish the analog-to-digital conversion of receiving intermediate frequency signal, 5021 are the Digital Down Convert unit, finish digital filtering and shaping filter to the digital signal that receives

Calculating section: 5022 are standing-wave ratio calculating unit, finish the standing-wave ratio of system that 5021 digital signals that obtain are calculated, 5023 for radio frequency opens the light and the controlling of sampling unit, finish according to switching sequence control 5012 and 5014 shown in Figure 4, and the sampling of control 5020.

In sum, the present invention has realized following technique effect:

The SWR measurement apparatus and method that the present invention proposes are applicable to TDD radio communication system.The present invention proposes one and realize normal receive path, oppositely and the standing-wave ratio channel multiplexing of forward direction unification by the mode that adopts radio-frequency (RF) switch, realizing using normal receive path to be used for standing-wave ratio detects, utilize the characteristics of pilot tone simultaneously, realize the equivalent homogeny of preceding/backward power sampling by the preceding backward power of measurement pilot frequency, has degree of precision, can make simultaneously and need not independently preceding/inverse detection coupling circuit on the veneer, cost, veneer area all will significantly reduce, and reducing to reduce with cost for the radio-frequency module volume has important meaning.

Obviously, those skilled in the art should be understood that, above-mentioned each module of the present invention or each step can realize with the general calculation device, they can concentrate on the single calculation element, perhaps be distributed on the network that a plurality of calculation element forms, optionally, they can be realized with the executable program code of calculation element, thereby they are stored in the storage device, carry out by calculation element.Perhaps they are made into each integrated circuit modules respectively, perhaps a plurality of modules in them or step are made into the single integrated circuit module and realize.The invention is not restricted to any specific hardware and software combination like this.Should be understood that the variation in these concrete enforcements is conspicuous for a person skilled in the art, do not break away from spiritual protection range of the present invention.

The above is the preferred embodiments of the present invention only, is not limited to the present invention, and for a person skilled in the art, the present invention can have various changes and variation.Within the spirit and principles in the present invention all, any modification of being done, be equal to replacement, improvement etc., all should be included within protection scope of the present invention.

Claims (9)

1. the standing-wave ratio detecting method of a tdd communication systems is characterized in that, may further comprise the steps:

Step 1 at the SWR measurement time slot, by diverter switch, is carried out the forward signal sampling of SWR measurement signal earlier; At next SWR measurement time slot,, carry out the reverse signal sampling of SWR measurement signal by diverter switch; After the forward direction of coupling and reverse signal sent into digital to analog converter after by coupling channel, will send signal sampling here by digital to analog converter sampling device and quantize the sampling that obtains base band is handled in the back by Digital Down Convert data;

Step 2, try to achieve reflection coefficient by calculating | Γ _{_ AD}|,

$\left|{\mathrm{\Γ}}_{\_\mathrm{AD}}\right|=\sqrt{\frac{P_{b\_\mathrm{BB}}}{P_{a\_\mathrm{BB}}}}=C_{F\_R}{\mathrm{\α}}_b$ Perhaps

Perhaps $\left|{\mathrm{\Γ}}_{\_\mathrm{AD}}\right|=\mathrm{IFFT}\left[\frac{\mathrm{FFT}\left(b_{\_\mathrm{BB}}\right)}{\mathrm{FFT}\left(\underset{\‾}{a_{\_\mathrm{BB}}}\right)}\right]=C_{F\_R}{\mathrm{\α}}_b,$

Wherein the baseband sampling value of forward direction coupled signal is designated as: a _{_ BB_1}, a _{_ BB_2}... .., a _{_ BB_N}The baseband sampling value of reverse coupled signal is designated as: b _{_ BB_1}, b _{_ BB_2}... .., b _{_ BB_N}

According to current operating frequency, before the inquiry/the transmission characteristic difference correction table of inverse detection passage, according to following formula:

Transmission characteristic difference $C_{F\_R}\left(f_0\right)=C_{F\_R}\left(f_m\right)+\frac{C_{F\_R}\left(f_{m+1}\right)-C_{F\_R}\left(f_m\right)}{f_{m+1}-f_m}\·(f_0-f_m),$ F wherein _m≤ f ₀≤ f _M+1

By the back of tabling look-up its amplitude is fitted, draw the forward detection passage of current frequency and the transmission characteristic difference C of inverse detection passage _{F_R}(ω ₀); And

Step 3, according to reflection coefficient | Γ _{_ AD}| and transmission characteristic difference C _{F_R}(ω ₀) calculate standing-wave ratio VSWR:

$\mathrm{VSWR}=\frac{C_{F\_R}\left({\mathrm{\ω}}_0\right)+\left|{\mathrm{\Γ}}_{\_\mathrm{AD}}\right|}{C_{F\_R}\left({\mathrm{\ω}}_0\right)-\left|{\mathrm{\Γ}}_{\_\mathrm{AD}}\right|}.$

2. standing-wave ratio detecting method according to claim 1 is characterized in that, described step 1 may further comprise the steps:

At predetermined SWR measurement time slot, carry out the preceding/reverse signal sampling of forward/reverse earlier, use diverter switch to switch afterwards, at next SWR measurement time slot, carry out oppositely/the forward signal sampling; And,

According to reverse/forward signal of digital to analog converter sampling, by obtaining the preceding/reverse sampled signal of base band after Digital Down Convert and the filtering.

3. standing-wave ratio detecting method according to claim 2, it is characterized in that, the sampling of described execution forward/reverse coupled signal or is carried out oppositely/gap periods of forward direction coupled signal sampling depends on the frame period of the system that is adopted, promptly equivalent same signal between the cycle; The time of each sampled signal is to begin to finish to emission from the emission of SWR measurement time slot.

4. standing-wave ratio detecting method according to claim 3 is characterized in that, described execution forward/reverse signal coupling sampling, or carry out oppositely/switching cycle of forward direction coupling sampling is the multiple of 5ms or 5ms.

5. a standing wave ration detection device is characterized in that, comprising:

Before/reverse coupled signal sampling module, be used for the preceding/reverse signal of predetermined SWR measurement time slot being sampled by diverter switch, Digital Down Convert is adopted in the back, and the sampled signal of expecting is down-converted to base band;

Measurement of reflection-factor module is used for preceding/reverse baseband signal of obtaining according to sampling, calculates according to measurement of reflection-factor method, obtains reflection coefficient | Γ _{_ AD}|;

$\left|{\mathrm{\Γ}}_{\_\mathrm{AD}}\right|=\sqrt{\frac{P_{b\_\mathrm{BB}}}{P_{a\_\mathrm{BB}}}}=C_{F\_R}{\mathrm{\α}}_b$ Perhaps

Perhaps $\left|{\mathrm{\Γ}}_{\_\mathrm{AD}}\right|=\mathrm{IFFT}\left[\frac{\mathrm{FFT}\left(b_{\_\mathrm{BB}}\right)}{\mathrm{FFT}\left(\underset{\‾}{a_{\_\mathrm{BB}}}\right)}\right]{=C}_{F\_R}{\mathrm{\α}}_b,$

Wherein the baseband sampling value of forward direction coupled signal is designated as: a _{_ BB_1}, a _{_ BB_2}... .., a _{_ BB_N}The baseband sampling value of reverse coupled signal is designated as: b _{_ BB_1}, b _{_ BB_2}... .., b _{_ BB_N}

Before/the backward channel adjusting module, be used for according to current operating frequency, before the inquiry/the transmission characteristic difference correction table of inverse detection passage, according to following formula:

Transmission characteristic difference $C_{F\_R}\left(f_0\right)=C_{F\_R}\left(f_m\right)+\frac{C_{F\_R}\left(f_{m+1}\right)-C_{F\_R}\left(f_m\right)}{f_{m+1}-f_m}\·(f_0-f_m),$ F wherein _m≤ f ₀≤ f _M+1

Its amplitude is fitted, obtain the transmission characteristic difference C of the preceding/inverse detection passage under the current frequency _{F_R}(ω ₀); And

Standing-wave ratio is calculated module, is used to utilize following formula to use transmission characteristic difference C _{F_R}(ω) and reflection coefficient | Γ _{_ AD}| calculating voltage standing-wave ratio VSWR:

$\mathrm{VSWR}=\frac{C_{F\_R}\left({\mathrm{\ω}}_0\right)+\left|{\mathrm{\Γ}}_{\_\mathrm{AD}}\right|}{C_{F\_R}\left({\mathrm{\ω}}_0\right)-\left|{\mathrm{\Γ}}_{\_\mathrm{AD}}\right|}.$

6. standing wave ration detection device according to claim 5 is characterized in that, described SWR measurement module comprises:

Preceding/reverse coupled signal sampling module comprises: preceding/the reverse signal sampling module, be used at predetermined SWR measurement time slot, carry out the preceding/reverse signal sampling of forward/reverse earlier, use diverter switch to switch afterwards, at next SWR measurement time slot, carry out oppositely/the forward signal sampling; And

Digital Down Converter Module is used for the reverse/forward signal according to the digital to analog converter sampling, and by obtaining the preceding/reverse sampled signal of base band after Digital Down Convert and the filtering, the baseband sampling value of forward direction coupled signal is designated as: a _{_ BB_1}, a _{_ BB_2}... .., a _{_ BB_N}The baseband sampling value of reverse coupled signal is designated as: b _{_ BB_1}, b _{_ BB_2}... .., b _{_ BB_N}

7. standing wave ration detection device according to claim 6, it is characterized in that, carry out the sampling of forward/reverse coupled signal, or the gap periods of carrying out reverse/forward direction coupled signal sampling depends on the frame period of the system that is adopted, be equivalent same signal between the cycle, the time cycle of each sampled signal is to begin to finish to emission from the emission of SWR measurement time slot.

8. standing wave ration detection device according to claim 7 is characterized in that, described execution forward/reverse signal coupling sampling, or carry out oppositely/switching cycle of forward direction coupling sampling is the multiple of 5ms or 5ms.

9. a standing wave ration detection device is characterized in that, comprising:

The Digital Up Convert unit is finished the shaping filter of baseband signal and is modulated to desired intermediate frequency;

D/A conversion unit, finishing digital signal transition is analog if signal;

The filtering to the emission medium-frequency signal of not expecting is finished in the intermediate frequency filtering unit;

The intermediate frequency amplifying unit is finished the amplification with intermediate-freuqncy signal;

The radio frequency that intermediate-freuqncy signal is transformed to expectation is finished in simulation up-conversion unit;

The filtering to the radio frequency transmissions of not expecting is finished in the rf filtering unit;

The radio frequency amplifying unit is finished the amplification of radiofrequency signal;

The duplex that transmits and receives is finished in the circulator unit;

The directional couple to preceding reverse signal is finished in the directional coupler unit;

The filtering of radio-frequency receiving-transmitting signal is finished in the front-end filtering unit;

Before/the reverser switch unit, the switch of finishing preceding/inverse detection switches;

Digital filtering and shaping filter to the digital signal that receives are finished in the Digital Down Convert unit;

The LNA big unit that receives, the low noise of finishing received signal amplifies;

Received RF filtering unit finishes receiving the filtering of the radiofrequency signal of not expecting;

Reception/sense switch switch unit, the switch of finishing reception/detection switches;

The analog down unit is finished the radiofrequency signal that will receive and is transformed to desired intermediate frequency;

Local oscillator power splitter unit is finished local oscillation signal merit branch is used to transmit and receive frequency conversion;

The generation of expectation local oscillation signal is finished in the local oscillator unit;

Receive the intermediate frequency filtering unit, finish the not filtering of desired intermediate frequency received signal;

Receive the intermediate frequency amplifying unit, finish amplification the intermediate-freuqncy signal that receives;

AD conversion unit is finished the analog-to-digital conversion of receiving intermediate frequency signal;

Standing-wave ratio is calculated the unit, finishes the standing-wave ratio that the digital signal that digital down-converter unit is obtained calculates system;

Radio frequency opens the light and the controlling of sampling unit, finishes switching sequence control LNA big unit and reception/sense switch switch unit, and the sampling of control AD conversion unit.

Images