CN101123595B - A method and system for gain calibration of digital receiver channel - Google Patents

Abstract

The invention provides a method and a system for digital receiver channel gain calibration. The method comprises that step one, a calibrating digital receiver sets up a communication connection with a control mainframe after the opening of the receiver; step two, the digital receiver and the received calibration signals carry out an initial synchronization, and the control mainframe and the digital receiver carry out an initial channel gain alignment after the completion of the initial synchronization; step three, the control mainframe forecasts a control word step size, and determines a corresponding channel gain of the control word step size; step four, the control mainframe establishes a channel gain calibration table according to the recorded control word step size and the channel gain. With the art, the invention supports a simultaneous calibration of a plurality of receivers, which decreases calibration time of receivers and suits for a mass production of receivers. And due to a dynamic forecast for a channel gain control coefficient, the calibration speed is improved, the effect of thermal noise and noise coefficient of the receiver at a higher channel gain is eliminated, and the calibration precision is enhanced.

Description

A kind of method and system of digital receiver channel gain calibration

Technical field

The present invention relates to technology that receiver is calibrated, be meant a kind of method and system of digital receiver channel gain calibration especially.

Background technology

Fig. 1 is the structural representation of digital receiver commonly used, input signal enters receiver from input port, through Surface Acoustic Wave Filter (SAWF, Surface Acoustic Wave Filter) back arrives low noise amplifier (LNA, Low Noise Amplifier), in frequency mixer, do multiply operation by input signal behind the LNA and local oscillation signal, the output baseband signal, this baseband signal is through variable gain amplifier (VGA, VariableGain Amplifier) sends into sample circuit after the amplification, the digital signal of obtaining after the sampling enters digital baseband, carries out follow-up digital signal processing.Because the amplitude of input signal can be along with the application scenario, transmission environment, the variation of factors such as time and changing, so corresponding variation also can take place in the amplitude of the digital signal after the sampling in the digital baseband; Concerning receiver itself, the change of factors such as its operating state and working temperature also can influence the amplitude of digital signal in the digital baseband.

Existing digital receiver calibration system, usually be conceived to digital signal amplitude relation in input signal power and the digital baseband is calibrated, and set up relation between input signal power, automatic gain control (AGC, Automatic Gain Control) control voltage and the digital signal amplitude.But, because can realizing negative carrier usually, digital receiver makes an uproar, so existing calibration system can't solve the bigger problem of channel gain initial value error usually than demodulation for spread spectrum communication system; Present in addition calibration system can not be supported the calibration of a plurality of receivers, and calibration efficiency is lower, is not suitable for the needs of large-scale production.

Summary of the invention

The method and system that the purpose of this invention is to provide a kind of digital receiver channel gain calibration, solve in the existing digital receiver calibration system, it is lower and be not suitable for large-scale production to support a plurality of receivers to calibrate the calibration efficiency that causes simultaneously, and the sample circuit of existing calibration system can be subjected to the defectives such as adverse effect of thermal noise and receiver noise factor when channel gain is higher.

A kind of method of digital receiver channel gain calibration may further comprise the steps: step 1, and digital receiver start back to be calibrated establishes a communications link with main control system; Step 2, the calibrating signal of described digital receiver and reception is carried out initial synchronisation, and after described initial synchronisation was finished, this main control system carried out the initial channel gain with described digital receiver and aligns; Step 3, described main control system PREDICTIVE CONTROL word, and determine and the corresponding channel gain of this control word; Step 4, described main control system are formulated the channel gain calibration chart according to control word that is write down and described channel gain.

Said method, wherein, in the described step 1, further comprise after the described digital receiver start: this digital receiver at first sends starting-up signal to described main control system, after described main control system was received this starting-up signal, both sides connected by the initial handshake process.

Said method wherein, carries out initial synchronisation and further comprises: carries out initial synchronization at once and enter synchronous regime with described calibrating signal after the described digital receiver start in the described step 2; If described digital receiver has been in open state, the instruction that then receives described main control system starts Cell searching, enters synchronous regime with the described calibrating signal that searches.

Said method, wherein, the channel gain G of the described digital receiver of record and the corresponding relation of described control word in the described channel gain calibration chart; And described channel gain G is through the power p of the digital signal of over-sampling circuit sampling back formation in the digital baseband _DBBPower p with described calibrating signal _InDifference: G=p _DBB-p _In

Said method, wherein, the power p of described calibrating signal _InThere is least significant end p _{In, min}With most significant end p _{In, max}And there is maximum G in described channel gain G _MaxWith minimum value G _MinThere is desired value p in the power of described digital signal _DBB ^Target, and this desired value determined by digital receiver structure, type of device, then the maximum G of described channel gain _MaxWith minimum value G _MinBe expressed as respectively:

$G_{\max }=p_{\mathrm{DBB}}^{T\arg \mathrm{et}}-p_{\mathrm{in},\min };$ $G_{\min }=P_{\mathrm{DBB}}^{T\arg \mathrm{et}}-p_{\mathrm{in},\max }.$

Said method, wherein, initial channel gain alignment further comprises in the described step 2: the power that main control system is at first controlled described calibrating signal reaches its most significant end p _{In, max}, then the initial value of described channel gain is the minimum value G of this channel gain _MinAnd the actual measurement channel gain of each digital receiver is G _i, then the error of this channel gain initial value is: Δ G _i=G _i-G _MinThen this channel gain initial value is adjusted to G _MinRequired control word length is: Δ c _i=[Δ G _i/ k _i]; Then the control word of digital receiver is adjusted into: c _i=c _Min+ Δ c _iWherein, [] expression rounds; I is at least 1, and is not more than the number of the digital receiver that is connected; Channel gain control coefrficient k _iThe channel gain that the representation unit control word is adjusted; c _MinIt is the minimum value of the control word of described calibration when beginning.

Said method, wherein, described channel gain control coefrficient k _iBe initial value, and this initial value by the model of described digital receiver, batch determine.

Said method, wherein, main control system PREDICTIVE CONTROL word further comprises in the described step 3: according to formula $k_{i,n}=\frac{G_{i,n}-G_{i,n-1}}{c_{i,n}-c_{i,n-1}}$ Calculate current channel gain control coefrficient; According to formula Δ G _i=G _{I, n+1}-G _{I, n}Calculate the adjustment step-length of current described channel gain; The control word adjustment step-length of then next time adjusting is: c _{I, n+1}=c _{I, n}+ [Δ G _i/ k _{I, n}]; In the formula, G _{I, n}Be current channel gain, G _{I, n-1}Be the last channel gain of adjusting, G _{I, n+1}Be the destination channel gain of next time adjusting, c _{I, n}Be current control word, c _{I, n-1}It is the last control word of adjusting.

Said method, wherein, described channel gain is during near maximum, and the power that described main control system is controlled described calibrating signal is no more than the predetermined value that makes sample circuit saturated, and increases channel gain.

Said method, wherein, described formulation channel gain calibration chart further comprises: main control system adopts interpolation and/or curve fit that the data that write down in the calibration process are operated, and produces the channel gain calibration chart, and this channel gain calibration chart is sent to described digital receiver.

A kind of system of digital receiver channel gain calibration comprises at least one calibration station, main control system, signal generator, power divider; Described calibration station is used to connect digital receiver; Described main control system connects each described calibration station by control bus, and control is positioned at the mode of operation of the described digital receiver of described calibration station, and adjusts the mode of operation and the relevant parameter of described signal generator; After obtaining calibration data, handle those calibration data and generate the channel gain calibration chart; Described signal generator is used to produce the original calibrated signal, and this original calibrated signal is passed through holding wire input Power Distribution device; Described power divider is connected by the described calibration station of holding wire and each, is used for described original calibrated signal allocation to the described digital receiver that is positioned on each described calibration station.

Said system, wherein, the passage of described digital receiver comprises Surface Acoustic Wave Filter, low noise amplifier, frequency mixer, variable gain amplifier at least; The channel gain of this passage is controlled by digital baseband;

Described digital baseband generates the automatic gain control word, and this control word forms voltage signal through digital-to-analogue conversion and is input to the gain control end of variable gain amplifier, and this voltage signal is controlled the gain of described variable gain amplifier.

Said system, wherein, the described original calibrated signal that described signal generator sends is by described power divider uniform distribution, calibrating signal after the distribution is imported each and is positioned at described digital receiver on the described calibration station, and when the power of the calibrating signal after the described distribution was lower than predetermined value, the calibration station that described power divider connects no longer increased.

Said system, wherein, the channel gain G of the described digital receiver of record and the corresponding relation of described control word in the described channel gain calibration chart; And described channel gain G is through the power p of the digital signal of over-sampling circuit sampling back formation in the digital baseband _DBBPower p with described calibrating signal _InDifference: G=p _DBB-p _In

Use the method and system of this digital receiver channel gain calibration provided by the invention, because supporting multi-receiver calibrates simultaneously, the alignment time and the instrument and equipment use cost of receiver are significantly reduced, use when therefore calibration steps of the present invention and system are fit to receiver large-scale production; Because the channel gain control coefrficient is carried out dynamic prediction, make gain adjust quick and precisely, improved calibration speed; Eliminate the influence of channel gain thermal noise and receiver noise factor when higher simultaneously, improved calibration accuracy.

Description of drawings

Fig. 1 is the structural representation of embodiment of the invention digital receiver commonly used;

The system configuration schematic diagram that Fig. 2 calibrates the channel gain of a plurality of digital receivers for the embodiment of the invention.

Embodiment

For making purpose of the present invention, technical characterictic and implementation result clearer, below in conjunction with the accompanying drawings and the specific embodiments technical scheme of the present invention is described in detail.

The method and system that the purpose of this invention is to provide a kind of digital receiver channel gain calibration is an example with the described digital receiver commonly used of Fig. 1, and the digital receiver passage generally includes components and parts such as SAWF, LNA, frequency mixer, VGA.Since the inconsistency of device, the influence of factors such as production technology deviation, and the channel gain of different digital receivers under same VGA control voltage may be different; In order to adjust to normal amplitude to the analog input signal that enters into sample circuit rapidly and accurately, also can satisfy the requirement of system design, simultaneously also cause that for the changes in amplitude of the digital signal of eliminating the input digit base band receiver performance worsens for the certainty of measurement that guarantees system; This just need be in the receiver row of channels gain calibration of advancing of dispatching from the factory, cancellation receiver individuality difference, these calibrations have generally included: digital baseband is according to the adjustment needs to channel gain, generate corresponding AGC control word, this AGC control word forms the gain control end that voltage signal is input to VGA after by digital-to-analogue conversion, guarantees that with this analog input signal that enters into sample circuit is in normal amplitude constantly; The calibration process to channel gain that hence one can see that sees from digital baseband is exactly in fact a process of setting up the corresponding relation of AGC control word and channel gain; Receiver need be measured the parameters such as power of the input signal of antenna port, this just requires receiver except needs detect the power of the digital signal in the digital baseband, also need to know the channel gain of this digital receiver, go out the parameters such as power of the input signal of antenna port according to these two calculation of parameter.

Need to prove, Fig. 1 is a kind of typical digital receiver structural principle schematic diagram, it is a preferred embodiment of the present invention, but do not represent that technology of the present invention can only be applicable to receiver shown in Figure 1, in fact as long as digital baseband can pass through the channel gain of receiver control someway, and this accurate control relation need could determine that the present invention just can be suitable for by calibration.

The structure of digital receiver channel gain calibration system mainly comprises main control system 201 as shown in Figure 2, calibration station 202, digital receiver 203, signal generator 204 and power divider 205; Described calibration station 202 can have a plurality of, and its concrete number can be determined according to the parameter and power divider 205 parameters of selected signal generator 204.

Main control system 201 is used for the mode of operation of control figure receiver 203, and adjusts the mode of operation and the parameter of signal generator 204, and after obtaining calibration data, handles those calibration data and generate the channel gain calibration chart.

Signal generator 204 is used to produce original calibrated signal s _Ref, and with this original calibrated signal input Power Distribution device 205.

The original calibrated signal allocation that power divider 205 is used for described signal generator 204 is produced is to each digital receiver 203 above calibration station 202.

The calculating of the channel gain of digital receiver 203 is realized that by following formula in digital baseband, the average power of digital signal can be expressed as:

$P_{\mathrm{DBB}}^W=\frac{1}{N}\underset{n=1}{\overset{N}{\mathrm{\Σ}}}{\left|I_n\right|}^2+{\left|Q_n\right|}^2---\left(1\right)$

P wherein _DBB ^WBe the digital power signal in the digital baseband, N is the sampled point number that the analog input signal that enters into sample circuit is sampled, I _n, Q _nI road signal, Q road signal after then expression is sampled.The employing log unit is expressed as:

$p_{\mathrm{DDB}}=10*1g\frac{{\mathrm{<figure-callout\; id="1"\; label="P\; DBB\; W"\; filenames="S2007101213113E00011.png"\; state="\{\{state\}\}">P</figure-callout>}}_{\mathrm{DBB}W}^{}}{1\mathrm{mW}}---\left(2\right)$

1mW represents 1 milliwatt in the formula; And if do not specify that after this unit of power all is dBm, the unit of gain all would be dB.

The channel gain of digital receiver can be expressed as the difference power of the input signal of digital signal and antenna port:

G＝p _DBB-p _in (3)

In calibration process, p _DBBCan through type (1) and formula (2) calculate p _InBe the power of the input signal of receiver antenna port, can obtain, calculate channel gain G according to formula (3) thus by the operating state and the running parameter of request signal generator 204.And least significant end p corresponding to the calibrating signal dynamic range _{In, min}With most significant end p _{In, max}, the dynamic range of receiver channel gain also has maximum and minimum value, is designated as G _MaxAnd G _Min, and G _MaxThe least significant end of corresponding calibrating signal dynamic range, G _MinThe most significant end of corresponding calibrating signal dynamic range, the desired value of establishing digital power signal is p _DBB ^Target, then the maximum of channel gain and minimum value can be expressed as:

$G_{\max }=p_{\mathrm{DBB}}^{T\arg \mathrm{et}}-p_{\mathrm{in},\min }---\left(4\right)$

$G_{\min }=P_{\mathrm{DBB}}^{T\arg \mathrm{et}}-p_{\mathrm{in},\max }---\left(5\right)$

The least significant end p of described calibrating signal dynamic range _{In, min}With most significant end p _{In, max}, concrete regulations such as common national standard mark, industry standard, the desired value p of digital power signal by the field of use _DBB ^TargetThen be when system design according to receiver structure, factors such as type of device are determined; Like this, when the receiver design is determined, G _MaxAnd G _MinAlso with regard to unique having determined.

When calculating digital power signal according to formula (1), the quantity of sampled point must be enough many, described enough being meant will reach and guarantee that the performance number that calculates can characterize the actual power of digital signal more, and the signal that is sent by signal generator 204 that calibration is used also must meet the requirement of digital receiver operate as normal, guarantees that digital signal can reflect the gain characteristic of passage truly.

The process that application said apparatus and formula are calibrated can be divided into steps A to step F according to different calibration phases, and the A. station detects, the B. initial synchronisation, and C. initial channel gain alignment, the prediction of D. step-length, the E. full dynamic range is calibrated, the F. data processing.

Steps A. station detects: the main purpose that station detects is to judge whether each station has digital receiver 203 to exist, when digital receiver 203 is connected to calibration station 202 and starts shooting, connect by the initial handshake process between this digital receiver 203 and the main control system 201, have digital receiver 203 thereby make main control system 201 know on this calibration station 202.

Step B. initial synchronisation: initial synchronisation is that digital receiver 203 is by carrying out the calibrating signal s that predefined synchronizing process and signal generator 204 produce _RefRealize synchronous process;

Initial synchronisation can be divided into a. start initial synchronisation, b. start back initial synchronisation:

A. the initial synchronisation of starting shooting be begin at once after digital receiver 203 start to carry out synchronizing process and with the calibrating signal s of signal generator 204 _RefEnter the process of synchronous regime;

B. start back initial synchronisation be digital receiver 203 under open state, receive the instruction of main control system 201 by control bus, start cell search process and with the calibrating signal s of signal generator 204 _RefEnter the process of synchronous regime.

After completing successfully this initial synchronisation, digital receiver 203 can constantly receive the calibrating signal that signal generator 204 produces and keep and signal generator 204 between synchronous regime.

Following step C has described when calibration process begins to step F, after the digital receiver 203 process initial channel gain alignment of each calibration station 202 of main control system 201 controls, from the smallest passage gain G _MinBegin calibration, after this main control system 201 is by the step-length prediction, and the channel gain of controlling the digital receiver 203 of each calibration station 202 rises synchronously, specifically comprises:

Step C. initial channel gain alignment: after calibration process began, main control system 201 sent instruction for each digital receiver 203, makes it begin to carry out the channel gain calibration; Main control system 201 is the most significant end P of control-signals generator 204 generation calibrating signal dynamic ranges at first _{In, max}, and because digital receiver 203 may not calibrated through channel gain before this, therefore the AGC control word of using this moment is not the minimum value G of channel gain dynamic range usually _Min

Suppose that the initial channel gain is the minimum value G of channel gain dynamic range _Min, each actual measurement channel gain of calibrating the digital receiver 203 above the station 202 is G _i, then the channel gain error can be expressed as:

ΔG _i＝G _i-G _min (6)

For digital receiver 203, for channel gain is adjusted to G _Min, the AGC control word length that needs to adjust is:

Δc _i＝[-ΔG _i/k _i] (7)

Wherein [] expression rounds, and i is at least 1, and is not more than the number of the digital receiver that is connected, k _iBe the channel gain control coefrficient, the channel gain that the representation unit control word can be adjusted, formula (11), k are seen in its definition _iInitial value can be according to the model of receiver, batch etc. factor determine.

For the initial channel gain G of aliging _Min, then the AGC control word of digital receiver 203 can be adjusted into:

c _i＝c _min+Δc _i (8)

C wherein _MinBe the minimum AGC control word of using in when beginning calibration, can be according to receiver model and batch definite.

After above-mentioned initial channel gain alignment, as long as the difference between the initial channel gain of each digital receiver 203 can narrow down in the certain limit, in fact k _iInitial value and c _MinIt is suitable to select, and the difference between the initial channel gain of each digital receiver 203 can not surpass 2dB; In the actual alignment process, if the alignment of initial channel gain for the first time back gain error is still bigger, can carry out alignment operation again one time, after alignment for the second time, the conclusion that draws according to practice is that the error of the channel gain of this moment is no more than 1dB usually.

Step D. step-length prediction: in the calibration process after initial channel gain alignment, adjust to target gain rapidly and accurately in order to make digital receiver 203, just need to dope more exactly AGC control coefrficient k, because control coefrficient be one with the receiver model, batch and the relevant parameter of scope of current channel gain, therefore in calibration process according to the dynamic prediction step of current calibration data.

For AGC control word more among a small circle, channel gain can be similar to thinks to become with the numerical values recited of this AGC control word the function of first order relation; If current digital receiver 203 channel gains are G _{I, n}, power control ratio is k _{I, n}, the destination channel gain of next time adjusting is G _{1, n+1}, then channel gain adjustment step-length is:

ΔG _i＝G _i，n+1-G _i，n (9)

Then AGC control word adjustment step-length is:

c _i，n+1＝G _i，n+[ΔG _i/k _i，n] (10)

Gain control coefficient k in the formula (10) _{I, n}For:

$k_{i,n}=\frac{G_{i,n}-G_{i,n-1}}{c_{i,n}-c_{i,n-1}}---\left(11\right)$

In the formula, G _{I, n}Be current channel gain, G _{I, n-1}Be the last channel gain of adjusting, G _{I, n+1}Be the destination channel gain of next time adjusting, c _{I, n}Be the step-length of current control word, c _{I, n-1}Be the step-length of the control word of last time adjustment, therefore as can be known by formula (11), the gain control coefficient that once actual gain control coefficient is predicted as current step-length before using in the native system.

Step e. full dynamic range calibration: can calculate the power of digital signal exactly in order to guarantee digital receiver 203, main control system 201 is adjusted the power output of signal generator 204 in time according to current channel gain, makes the digital power signal that arrives digital baseband be positioned at p _DBB ^TargetNear.

Channel gain at the digital receiver 203 of certain station reaches maximum gain G _MaxAfter, main control system 201 stops the calibration of the channel gain of this receiver, when the gain of the receiver channel of all stations all reaches G _MaxAfter, main control system 201 can stop the full dynamic range calibration process.In the full dynamic range calibration process, the channel gain that AGC control word when main control system 201 is noted each adjustment the and actual measurement obtain is in order to follow-up data processing.

What need further specify is; in the time of near channel gain G is positioned at maximum; because the influence of thermal noise and receiver noise factor; the signal to noise ratio of the digital signal in the digital baseband more serious deterioration can occur usually; in order to eliminate the considerable influence that signal-to-noise ratio degradation brings for the power measurement of digital baseband, when channel gain when the highest, can no longer reduce input signal power; if progressively increase channel gain G this moment, the power of digital signal can be higher than design load p _DBB ^Target, but as long as calibrating signal does not make sample circuit saturated, just can ignore the error of measurement substantially, this method can overcome the problem of being forbidden in the most significant end measurement of channel gain G in the existing calibration system.

Step F. data processing: in the full dynamic range calibration process, in order to accelerate calibration speed, channel gain G can be with big step-length adjustment when measuring at every turn.In the process of receiver real work, in order accurately to adjust channel gain, usually need high-precision channel gain calibration chart, in order to satisfy the operation of receiver needs, main control system 201 must be handled the data that write down in the calibration process, and the way by interpolation or curve fit produces and satisfies the calibration chart that real work requires.

The digital receiver quantity that the present invention supported only is subjected to the restriction of signal generator power output, therefore by the relation between sense channel gain and the AGC control word, can support the multi-section receiver to calibrate simultaneously.Owing to support multi-receiver to calibrate simultaneously, the alignment time of receiver and instrument and equipment use cost are significantly reduced, so native system use when being fit to receiver large-scale production; Because the channel gain control coefrficient is carried out dynamic prediction, make gain adjust quick and precisely, improved calibration speed, eliminate the influence of channel gain thermal noise and receiver noise factor when higher simultaneously, improved calibration accuracy.

Should be noted that above embodiment is only unrestricted in order to technical scheme of the present invention to be described, all parameter values can be according to the actual conditions adjustment, and in this rights protection scope.Those of ordinary skill in the art should be appreciated that and can make amendment or be equal to replacement technical scheme of the present invention, and do not break away from the spiritual scope of technical solution of the present invention, and it all should be encompassed in the middle of the claim scope of the present invention.

Claims (13)

1. the method for a digital receiver channel gain calibration is characterized in that, may further comprise the steps:

Step 1, digital receiver start back to be calibrated establishes a communications link with main control system;

Step 2, the calibrating signal of described digital receiver and reception is carried out initial synchronisation, and after described initial synchronisation was finished, this main control system carried out the initial channel gain with described digital receiver and aligns;

Step 3, described main control system PREDICTIVE CONTROL word step-length, and determine and the corresponding channel gain of this control word step-length, comprising:

According to formula Calculate current channel gain control coefrficient; According to formula Δ G _i=G _{I, n+1}-G _{I, n}Calculate the adjustment step-length of current described channel gain; The control word adjustment step-length of then next time adjusting is: c _{I, n+1}=c _{I, n}+ [Δ G _i/ k _{I, n}], wherein, [] expression rounds;

In the formula, G _{I, n}Be current channel gain, G _{I, n-1}Be the last channel gain of adjusting, G _{I, n+1}Be the destination channel gain of next time adjusting, c _{I, n}Be current control word, c _{I, n-1}It is the last control word of adjusting;

Step 4, described main control system are formulated the channel gain calibration chart according to control word that is write down and described channel gain.

2. method according to claim 1, it is characterized in that, in the described step 1, further comprise after the described digital receiver start: this digital receiver at first sends starting-up signal to described main control system, after described main control system was received this starting-up signal, both sides connected by the initial handshake process.

3. method according to claim 1 is characterized in that, carries out initial synchronisation in the described step 2 and further comprises:

At once carry out initial synchronization and enter synchronous regime after the described digital receiver start with described calibrating signal;

If described digital receiver has been in open state, the instruction that then receives described main control system starts Cell searching, enters synchronous regime with the described calibrating signal that searches.

4. method according to claim 1 is characterized in that, the channel gain G of the described digital receiver of record and the corresponding relation of described control word in the described channel gain calibration chart; And described channel gain G is through the power p of the digital signal of over-sampling circuit sampling back formation in the digital baseband _DBBPower p with described calibrating signal _InDifference: G=p _DBB-p _In

5. method according to claim 4 is characterized in that, the power p of described calibrating signal _InThere is least significant end p _{In, min}With most significant end p _{In, max}And there is maximum G in described channel gain G _MaxWith minimum value G _MinThere is desired value p in the power of described digital signal _DBB ^Target, and this desired value determined by digital receiver structure, type of device, then the maximum G of described channel gain _MaxWith minimum value G _MinBe expressed as respectively:

6. method according to claim 1 or 5 is characterized in that, initial channel gain alignment further comprises in the described step 2:

The power that main control system is at first controlled described calibrating signal reaches its most significant end p _{In, max}, then the initial value of described channel gain is the minimum value G of this channel gain _MinAnd the actual measurement channel gain of each digital receiver is G _i, then the error of this channel gain initial value is: Δ G _i=G _i-G _Min

Then this channel gain initial value is adjusted to G _MinRequired control word length is: Δ c _i=[Δ G _i/ k _i]; Then the control word of digital receiver is adjusted into: c _i=c _Min+ Δ c _i

Wherein, [] expression rounds; I is at least 1, and is not more than the number of the digital receiver that is connected; Channel gain control coefrficient k _iThe channel gain that the representation unit control word is adjusted; c _MinIt is the minimum value of the control word of described calibration when beginning.

7. method according to claim 6 is characterized in that, described channel gain control coefrficient k _iBe initial value, and this initial value by the model of described digital receiver, batch determine.

8. method according to claim 1 is characterized in that, described channel gain is during near maximum, and the power that described main control system is controlled described calibrating signal is no more than the predetermined value that makes sample circuit saturated, and increases channel gain.

9. method according to claim 1, it is characterized in that, described formulation channel gain calibration chart further comprises: main control system adopts interpolation and/or curve fit that the data that write down in the calibration process are operated, and produce the channel gain calibration chart, this channel gain calibration chart is sent to described digital receiver.

10. the system of a digital receiver channel gain calibration is characterized in that, comprises at least one calibration station, main control system, signal generator, power divider;

Described calibration station is used to connect digital receiver;

Described main control system connects each described calibration station by control bus, is used to control the mode of operation of the described digital receiver that is positioned at described calibration station, and adjusts the mode of operation and the relevant parameter of described signal generator; Main control system PREDICTIVE CONTROL word step-length, and determine and the corresponding channel gain of this control word step-length, comprising:

According to formula

Calculate current channel gain control coefrficient; According to formula Δ G _i=G _{I, n+1}-G _{I, n}Calculate the adjustment step-length of current described channel gain; The control word adjustment step-length of then next time adjusting is: c _{I, n+1}=c _{I, n}+ [Δ G _i/ k _{I, n}], wherein, [] expression rounds;

In the formula, G _{I, n}Be current channel gain, G _{I, n-1}Be the last channel gain of adjusting, G _{I, n+1}Be the destination channel gain of next time adjusting, c _{I, n}Be current control word, c _{I, n-1}It is the last control word of adjusting;

Generate the channel gain calibration chart according to control word that is write down and described channel gain;

Described signal generator is used to produce the original calibrated signal, and this original calibrated signal is passed through holding wire input Power Distribution device;

Described power divider is connected by the described calibration station of holding wire and each, is used for described original calibrated signal allocation to the described digital receiver that is positioned on each described calibration station.

11. system according to claim 10 is characterized in that, the passage of described digital receiver comprises Surface Acoustic Wave Filter, low noise amplifier, frequency mixer, variable gain amplifier at least; The channel gain of this passage is controlled by digital baseband;

Described digital baseband generates the automatic gain control word, and this control word forms voltage signal through digital-to-analogue conversion and is input to the gain control end of variable gain amplifier, and this voltage signal is controlled the gain of described variable gain amplifier.

12. system according to claim 10, it is characterized in that, the described original calibrated signal that described signal generator sends is by described power divider uniform distribution, calibrating signal after the distribution is imported each and is positioned at described digital receiver on the described calibration station, and when the power of the calibrating signal after the described distribution was lower than predetermined value, the calibration station that described power divider connects no longer increased.

13. system according to claim 10 is characterized in that, the channel gain G of the described digital receiver of record and the corresponding relation of described control word in the described channel gain calibration chart; And described channel gain G is through the power p of the digital signal of over-sampling circuit sampling back formation in the digital baseband _DBBPower p with described calibrating signal _InDifference: G=p _DBB-p _In

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