CN102088321A - Calibration method of time division-synchronization code division multiple access (TD-SCDMA) terminal - Google Patents

Abstract

The invention discloses a calibration method of a time division-synchronization code division multiple access (TD-SCDMA) terminal, which increases terminal calibration speed and enhances terminal calibration accuracy. The technical scheme comprises three aspects, namely automatic frequency control calibration, automatic gain control calibration and automatic power control calibration, wherein the automatic frequency control calibration comprises the following steps of: under the fixed input signal power of a signal source, changing a control word; demodulating to acquire data of a plurality of frames; calculating frequency information; and performing linear variation to acquire a step change value and an automatic frequency control initial value; the automatic gain control calibration comprise the following steps of: under the fixed input signal power of the signal source, changing the control word to acquire a plurality of groups of receiving signal intensity values, a gain value of a fixed gain module and a gain slope of a variable gain module; calculating input signal power and a gain value and combining automatic gain calibration tables; and the automatic power control calibration comprises the following steps of: transmitting a power list by gradually increasing or decreasing control words at a fixed periodic interval by using the terminal; acquiring data by using a frequency spectrograph; and selecting a power value and a control word.

Description

A kind of calibration steps of TD-SCDMA terminal

Technical field

The present invention relates to the calibration steps of terminal phone, relate in particular to quick A FC (automatic frequency control), AGC (automatic gain control), APC (automated power control) calibration steps of a kind of TD-SCDMA of being applied to (TD SDMA access).

Background technology

The AFC calibration of at present relevant mobile phone, adopt the Tx technology mostly, be that UE emission modulation signal is to frequency spectrograph or comprehensive test instrument, instrument demodulates frequency information, portable terminal (UE) changes the AFC control word, circulation once more, and computer is according to the frequency information that obtains from instrument then, calculate frequency step and frequency initial value, finish calibration.

The AGC calibration of at present relevant mobile phone, all there is design separately in each producer of measurement of received signal intensity (RSSI), therefore the calibration of RSSI precision also is each have their own method, but principle is consistent substantially, that is exactly to be consistent in demodulation front signal size in order to guarantee under the received signals of different sizes.All individual agc circuit can be arranged in the circuit, multiplication factor and RSSI during AGC work are linearly proportional; So the multiplication factor of calibrating AGC, the output result of assurance AGC is exactly that the RSSI precision is being calibrated, and present most of producers all call the AGC calibration to the calibration of RSSI precision.The AGC calibration steps generally is that the signal that applies a known dimensions is given travelling carriage, by travelling carriage report RSSI, the RSSI of travelling carriage report and the error of actual value are exactly the error of AGC, from this point also as can be seen, the calibration of AGC is to finish by the report of travelling carriage RSSI.Usually, the AGC calibration steps that is applied to TD-SCDMA is: because radiofrequency receiving chip has better linearity, so the algorithm of calibration is surveyed two points exactly, draw straight line then.The following formula of general employing:

$\left[\begin{array}{c}{P}_1\\ P_2\\ \·\\ \·\\ \·\\ P_N\end{array}\right]+\left[\begin{array}{c}{G}_1\\ G_2\\ \·\\ \·\\ \·\\ G_N\end{array}\right]=\mathrm{RSSI}$

Wherein, P ₁, P ₂... P _NBe input signal power, G ₁, G ₂... G _NBe gain, RSSI is the received signal intensity level.Promptly in input signal power, constantly change gain, thus the RSSI value that is fixed, change input signal power then, constantly change gain again, thus the RSSI value that is fixed, utilize the slope of input signal power and the slope of corresponding gain, finish calibration.The shortcoming of this method is the power that need change repeatedly instrument, and needs to change more frequently gain, thereby has reduced the efficient of calibration, again because digital to analog converter (DAC) non-linear can produce certain influence to calibration accuracy.

The APC calibration of at present relevant mobile phone is adopted mostly to UE transmission power control word, and UE launches corresponding power to instrument, and computer collects power information; Change the power control word then, move in circles, so-called one point method when forming the APC calibration, two-point method, line-of-sight course or multiple spot more.Simulate a curve then, obtain desired power point and corresponding power control word according to curve.If count very little, its precision is not high, not necessarily can satisfy the requirement of 3GPP agreement, and the mobile phone individual difference is difficult to control during to production in enormous quantities.Too many if count, though improved the precision of calibration, calibration speed is very influenced.

Summary of the invention

The object of the present invention is to provide a kind of quick calibration method of the TD-SCDMA terminal on signal source, frequency spectrograph, improved calibration speed and precision.

Technical scheme of the present invention is: the present invention has disclosed a kind of calibration steps of TD-SCDMA terminal, comprises three aspects of automatic frequency control calibration, automatic gain control calibration and automated power control calibration, wherein:

This comprises automatic frequency control calibration on the one hand:

Under the input signal power that signal source is fixed, change the control word of automatic frequency control, after the terminal demodulation, obtain the multiframe data, utilize FFT to calculate corresponding frequency information, think that then frequency linearity changes, thereby the automatic frequency control initial value when obtaining the step change value of automatic frequency control and frequency and being zero is finished the calibration of automatic frequency control;

This comprises automatic gain control calibration on the one hand:

Under the input signal power that signal source is fixed, change the control word of automatic gain control, obtain many group of received signal strength values, adopt the mode retrodict to obtain the yield value of fixed gain module of terminal and the gain slope of variable gain module then, thereby calculate varying input signal power and pairing yield value under the situation of fixing received signal intensity level, the automatic gain calibration table that merges each signal power section is at last finished the calibration of automatic gain control to form complete automatic gain calibration table;

This comprises automated power control calibration on the one hand:

Terminal every a fixed cycle with the mode list of transmission power of the control word increasing or decreasing of automated power control to frequency spectrograph, choose performance number and corresponding control word by this frequency spectrograph image data and by computer, finish the calibration of automated power control.

Embodiment according to the calibration steps of TD-SCDMA terminal of the present invention, the control word that changes automatic frequency control for passing through in the automatic gain control calibration obtains the step of many group of received signal strength values, is constantly to produce the gain stepping to obtain this many group of received signal strength values by the digital signal processor by using circulation.

Embodiment according to the calibration steps of TD-SCDMA terminal of the present invention, obtain the step of many group RSSI values for the control word that passing through the control of change automatic frequency in the automatic gain control calibration, be to have linearity, by changing four yield values to obtain four groups of RSSI values by receiving chip.

According to an embodiment of the calibration steps of TD-SCDMA terminal of the present invention, in the time of can't containing scope from the minimum power to the maximum power for the dynamic range at frequency spectrograph in the automated power control calibration, frequency spectrograph is divided into the multistage image data.

According to an embodiment of the calibration steps of TD-SCDMA terminal of the present invention, the process for automated power control calibration further comprises:

The terminal emission is preset the power list of power to frequency spectrograph less than one;

Frequency spectrograph triggers each performance number, and computer receives those performance numbers, if the control word stepping is not 1 bit, then chooses suitable power and corresponding power control word thereof after the linear interpolation;

Terminal emission more than or equal to the power list of this default power to frequency spectrograph;

Frequency spectrograph triggers each performance number, and computer receives those performance numbers, if the control word stepping is not 1 bit, then chooses suitable power and corresponding power control word thereof after the linear interpolation;

Merge automatic power control and calibration gauge, finish calibration.

The present invention contrasts prior art, following beneficial effect is arranged: what the present invention adopted is the pattern that signal source adds frequency spectrograph, when calibrating, AFC, AGC only need the fixing output of signal once or twice of signal source, reduce instrument and changed the output number of times, reduce the loop iteration number of times, greatly improved the speed of calibration.And the present invention can greatly improve calibration accuracy to AGC, concerning AGC, suppose to have three gain modules, wherein two is fixed gain, and one is variable gain module, adopt the simplest method, can export signal one time, change four times the gain controlling word, obtain RSSI four times, just can obtain all AGC calibration parameter tables, also can keep calibration accuracy preferably.APC is calibrated, can adopt power list mode, the gain stepping can be every bit, every 2bit, or other are according to the mode transmitted power of the gain controlling word increasing or decreasing of certain mathematical law, collect after the performance number according to directly choosing or adopting the mode of curve fit to finish calibration.The contrast prior art, method of the present invention can improve calibration speed and precision, and can to other standards for example the mobile phone of 2G standard carry out AFC, AGC, APC calibration, thereby improve the utilization ratio of instrument.

Description of drawings

Fig. 1 is the flow chart of preferred embodiment of the calibration steps of TD-SCDMA terminal of the present invention.

Fig. 2 is the flow chart of preferred embodiment of the AFC calibration of TD-SCDMA terminal of the present invention.

Fig. 3 is the flow chart of preferred embodiment of the AGC calibration of TD-SCDMA terminal of the present invention.

Fig. 4 is the flow chart of preferred embodiment of the APC calibration of TD-SCDMA terminal of the present invention.

Embodiment

The invention will be further described below in conjunction with drawings and Examples.

Fig. 1 shows the flow process of preferred embodiment of the calibration steps of TD-SCDMA terminal of the present invention.See also Fig. 1, the calibration of TD-SCDMA terminal is comprised that AFC calibration (step S10), AGC calibration (step S20) and APC calibrate (step S30) these three aspects, there is not the sequencing in the execution in the calibration of these three aspects.

Describe with regard to the calibration of these three aspects respectively below.

For AFC calibration, calibration institute based on formula be: y=kx+b, wherein x is the control word of AFC, y is that k is the caused frequency step of frequency control word stepping by the frequency values of frequency control word generation, b is that frequency values is 0 o'clock a initial value.By changing x twice, obtain y twice, can calculate k and b, finish the AFC calibration.

The step of AFC calibration as shown in Figure 2, at first under the input signal power that signal source is fixed, change the value of frequency control word twice, obtain I/Q (In-phase/Quadrature twice after DSP (digital processing chip) demodulation by terminal, quadrature in the same way) a frame or multiframe data send to computer (step S100).Then, computer utilizes FFT to calculate wherein twice frequency information respectively, thinks that frequency is a linear change, in the above-mentioned formula of substitution immediately, obtains corresponding k and the value of b, finishes AFC calibration (step S101).

For the AGC calibration, in AGC calibration of the present invention, calculate the yield value of fixed gain module and utilize computer to retrodict, finish the AGC calibration.Gain module is divided into fixed gain module and variable gain module, owing to be that small-signal receives, the yield value of fixed gain module is constant substantially.

$P+\left[\begin{array}{c}{G}_1\\ G_2\\ \·\\ \·\\ \·\\ G_N\end{array}\right]=\left[\begin{array}{c}{\mathrm{RSSI}}_1\\ {\mathrm{RSSI}}_2\\ \·\\ \·\\ \·\\ {\mathrm{RSSI}}_N\end{array}\right]\→\left[\begin{array}{c}{P}_1\\ P_2\\ \·\\ \·\\ \·\\ P_N\end{array}\right]+\left[\begin{array}{c}{G}_1\\ G_2\\ \·\\ \·\\ \·\\ G_N\end{array}\right]=\mathrm{RSSI}$

Wherein P is the input signal power of fixing, G ₁, G ₂... G _NBe variable gain, RSSI ₁, RSSI ₂, RSSI _NBe and G ₁, G ₂... G _NCorresponding received signal intensity level; P ₁, P ₂... P _NBe variable input signal power, G ₁, G ₂... G _NBe variable gain, RSSI is the received signal intensity level of fixing.

At first, under the input signal power that signal source is fixed, constantly change yield value, obtain corresponding RSSI value (step S200) by changing the AGC control word.Adopt the method for retrodicting to calculate the yield value of fixed gain module and the slope of variable gain module then, thereby calculate varying input signal power and pairing yield value (step S201) under the situation of fixing RSSI value.The AGC calibration chart that merges each signal power section is at last finished the calibration (step S202) of AGC to form complete AGC calibration chart.

In concrete application, can utilize circulation constantly to produce the gain stepping by machine master DSP, thereby obtain corresponding RSSI value.No longer having needed receiving chip whether to have linear this prerequisite in theory, only needed the dynamic range of modulus (AD) enough, makes an uproar and can ignore the influence of AD input signal power generation in its end.

In the real world applications process,, can utilize receiving chip to have linear this prerequisite if adopt the simply method of a bit, only change yield value four times, obtain RSSI four times, promptly cocoa obtains all AGC calibration parameter tables, certainly, its precision can than above-mentioned endless-walk gain inequality some.

AGC calibration steps of the present invention has very important directive significance, can be applied to the calibration of the mobile phone of multiple standard.

Below for illustrating, with signal power of the simplest input, changing four yield values is that the example explanation is calibrated under the dynamic condition of limited of AD, suppose that receive path has LNA, Mixer, three gain function modules of VGA, LNA wherein, Mixer is the gain module with fixed gain, and VGA is a variable gain module, and the mode that is applied to the gain controlling word is:

LNA、Mixer?low?gain： 0x0000->0x03FF；

LNA?low?gain，Mixer?high?gain： 0x4000->0x43FF；

LNA?high?gain，Mixer?low?gain： 0x8000->0x83FF；

LNA?Mixer?high?gain： 0xC000->0xC3FF；

The calibration purpose be:

Input signal power :-10dBm～-39dBm is employing LNA, Mixer low gain,

Input signal power :-40dBm～-69dBm is employing LNA high gain, Mixer lowgain;

Input signal power≤-69dBm is employing LNA, Mixer high gain.

Obtain the gain controlling word of AGC under the situation that input power changes, it is constant to satisfy RSSI maintenance-10dBm, is that C3FF also can't satisfy RSSI maintenance-10dBm up to the little gain controlling word to AGC of input power.

The number of significant digit of supposing AD is 8bit, and it dynamically is about 50dB; Full scale is 6dBm;

Suppose that calibration is 10054, (100KHz is a side-play amount, can change, and between 0～640KHz, generally gets 10KHz～600KHz) the instrument frequency then is set is 2010.8MHz+100KHz.

Suppose that the instrument power output is-50dBm, the gain controlling word that DSP is provided with AGC is 0x200, and DSP calculates RSSI and equals-35dBm; The gain controlling word that DSP is provided with AGC is 0x32C, and DSP calculates RSSI and equals-5dBm; Can get:

$-50+\left[\begin{array}{c}0x22C\\ 0x8100\\ 0x822C\\ 0\mathrm{xC}100\end{array}\right]=\left[\begin{array}{c}-15\\ -35\\ -5\\ -15\end{array}\right]$

$\left[\begin{array}{c}-10\\ -11\\ \·\\ \·\\ \·\\ -29\\ -30\\ -31\\ \·\\ \·\\ \·\\ -39\end{array}\right]+\left[\begin{array}{c}0x132\\ 0x13C\\ \·\\ \·\\ \·\\ 0x1F0\\ 0x1\mathrm{FA}\\ 0x204\\ \·\\ \·\\ \·\\ 0x254\end{array}\right]=-10$

Think that receive path is a linear passageway, the yield value that can obtain LNA, Mixer thus is 10dB, 20dB; Calculate the slope of VGA gain controlling word and RSSI then, can obtain under the constant situation of input signal power increasing by 10 when the gain controlling word, then RSSI increases 1dB, that is as signal power decline 1dB, for keeping RSSI to immobilize, then the gain controlling word must increase by 10; Then can calculate at input power-30dBm, during RSSI=-10dBm, the gain controlling word is 1FA, can calculate following AGC calibration chart:

When the instrument power output-40dBm～-during 69dBm, UE is set is in LNA high gain, Mixer low gain is 0x8000-〉0x83FF; Obtain the AGC calibration chart:

Input signal power-69dBm adopts LNA, Mixer high gain.Be 0x8000-〉0x83FF; Obtain the AGC calibration chart.At last three calibration charts are lumped together, form complete AGC calibration chart, promptly finish the AGC calibration.

Calibrate for APC, to frequency spectrograph, the APC control word stepping of power list can be 1bit, 2bit, 3bit or by the increasing or decreasing of certain mathematical law to terminal every for example every frame of a fixed cycle or every time slot list of transmission power (power list).Frequency spectrograph is in zero span (0span)

$\left[\begin{array}{c}-40\\ -41\\ \·\\ \·\\ \·\\ -69\end{array}\right]+\left[\begin{array}{c}0x81\mathrm{FA}\\ 0x8204\\ \·\\ \·\\ \·\\ 0x831C\end{array}\right]=-10$

Situation under trigger (can utilize video to trigger video trig or RF burst), in long time-base sweep (sweep time), pass to computer after the readout power data, then by computer according to mathematical operation curve fit etc. for example, the mode of perhaps directly choosing obtains desired power and corresponding control word.

Because the requirement of 3GPP agreement, the dynamic range of frequency spectrograph is not enough usually, can't contain scope so big from the minimum power to the maximum power, generally needs the branch multistage for example can be divided into two segment limits and grasps data.For example, terminal can be launched the power list of lower frequency earlier, launches more powerful power list then, thereby finishes calibration.Fig. 4 shows this process, and at first the power list of UE emission lower-wattage (such as less than a default power) is to frequency spectrograph (step S300).Frequency spectrograph triggers (trig) each performance number then, and computer is just chosen suitable power and corresponding power control word thereof from the performance number that collects, if stepping is not 1bit then chooses power after the first linear interpolation again and control word (step S301).The power list of UE emission more high-power (such as more than or equal to above-mentioned default power) is to frequency spectrograph (step S302).Frequency spectrograph triggers (trig) each performance number, computer is just chosen suitable power and corresponding control word thereof from the performance number that collects, if stepping is not 1bit then chooses suitable power after the first linear interpolation again and corresponding control word (step S303).Merge the APC calibration chart at last, finish calibration (step S304).

The foregoing description provides to those of ordinary skills and realizes or use of the present invention; those of ordinary skills can be under the situation that does not break away from invention thought of the present invention; the foregoing description is made various modifications or variation; thereby protection scope of the present invention do not limit by the foregoing description, and should be the maximum magnitude that meets the inventive features that claims mention.

Claims (5)

1. the calibration steps of a TD-SCDMA terminal comprises three aspects that automatic frequency control calibration, automatic gain control calibration and automated power control are calibrated, wherein:

This comprises automatic frequency control calibration on the one hand:

Under the input signal power that signal source is fixed, change the control word of automatic frequency control, after the terminal demodulation, obtain the multiframe data, utilize FFT to calculate corresponding frequency information, think that then frequency linearity changes, thereby the automatic frequency control initial value when obtaining the step change value of automatic frequency control and frequency and being zero is finished the calibration of automatic frequency control;

This comprises automatic gain control calibration on the one hand:

Under the input signal power that signal source is fixed, change the control word of automatic gain control, obtain many group of received signal strength values, adopt the mode retrodict to obtain the yield value of fixed gain module of terminal and the gain slope of variable gain module then, thereby calculate varying input signal power and pairing yield value under the situation of fixing received signal intensity level, the automatic gain calibration table that merges each signal power section is at last finished the calibration of automatic gain control to form complete automatic gain calibration table;

This comprises automated power control calibration on the one hand:

Terminal every a fixed cycle with the mode list of transmission power of the control word increasing or decreasing of automated power control to frequency spectrograph, choose performance number and corresponding control word by this frequency spectrograph image data and by computer, finish the calibration of automated power control.

2. the calibration steps of TD-SCDMA terminal according to claim 1, it is characterized in that, the control word that changes automatic frequency control for passing through in the automatic gain control calibration obtains the step of many group of received signal strength values, is constantly to produce the gain stepping to obtain this many group of received signal strength values by the digital signal processor by using circulation.

3. the calibration steps of TD-SCDMA terminal according to claim 1, it is characterized in that, obtain the step of many group RSSI values for the control word that passing through the control of change automatic frequency in the automatic gain control calibration, be to have linearity, by changing four yield values to obtain four groups of RSSI values by receiving chip.

4. the calibration steps of TD-SCDMA terminal according to claim 1 is characterized in that, in the time of can't containing scope from the minimum power to the maximum power for the dynamic range at frequency spectrograph in the automated power control calibration, frequency spectrograph is divided into the multistage image data.

5. the calibration steps of TD-SCDMA terminal according to claim 1 is characterized in that, the process for automated power control calibration further comprises:

The terminal emission is preset the power list of power to frequency spectrograph less than one;

Frequency spectrograph triggers each performance number, and computer receives those performance numbers, if the control word stepping is not 1 bit, then chooses suitable power and corresponding power control word thereof after the linear interpolation;

Terminal emission more than or equal to the power list of this default power to frequency spectrograph;

Frequency spectrograph triggers each performance number, and computer receives those performance numbers, if the control word stepping is not 1 bit, then chooses suitable power and corresponding power control word thereof after the linear interpolation;

Merge automatic power control and calibration gauge, finish calibration.

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