CN102316567A - Digital automatic gain control method and system thereof - Google Patents

Abstract

The invention provides a digital automatic gain control method and a system thereof. The method comprises the following steps that: a bit cutting output signal is feedbacked to carry out power statistics, so that an average power value is obtained; the average power value is compared with a preset strength grade parameter to obtain a corresponded step value and a corresponded gain adjusting direction value; according to the step value, the gain adjusting direction value and a preset initial gain value, a gain value is adjusted; the adjusted gain value is multiplied by an input signal to carry out gain compensation; and then a bit cutting output is carried out on a signal after the gain compensation. According to the digital automatic gain control method and the system thereof provided in the invention, an output signal after the bit cutting is feedbacked to carry out power statistics, so that a power state of a current output signal can be better reflected and strength fluctuation of the output signal is controlled in a certain range.

Description

Digital auto gain control method and system

Technical field

The present invention relates to the mobile communication technology field, relate in particular to digital auto gain control method and system in a kind of transmission process for digital signal.

Background technology

Mobile telecommunication channel is a kind of communication channel of complicacy, and it has characteristics such as rapid fading, slow fading and multipath stack, and dafing depth can reach tens dB, and this decline causes receiving signal and has very big variable power scope, worsens the demodulation performance of system.

Usually use the power of DAGC (Digital Automatic Gain Control, digital Auto Gain control) adjustment supplied with digital signal in the mobile telecommunication channel, make when input signal strength changes that the intensity of output signal can remain unchanged basically; And the output signal is carried out cut position handle, to reduce the realization burden of follow-up base band signal process algorithm, increase it and realize precision, reduce and realize bit wide.

Common DAGC can set an expectation threshold value as required, and the adjustment according to the error of intensity and the threshold value of output signal gains remains near the desired value so that export the intensity of signal.The choosing of desired value make the output signal keep the information of original signal as far as possible, excessive or too small expectation threshold value is set when adjustment, all can makes amount of information lose, and seriously reduces the performance of receiver.

Traditional DAGC system implementation is as shown in Figure 1, and Fig. 1 is the structural principle sketch map of a kind of DAGC of prior art system.Said DAGC system comprises gain regulation module 101, magnitude computing module 102, error comparison module 103 and low-pass filtering module 104.Input signal obtains exporting signal through after the gain regulation module 101; The intensity of 102 pairs of output of magnitude computing module signal is calculated; The intensity result calculated is sent in the error comparison module 103 and is compared with predefined expectation threshold value; According to result relatively, in low-pass filtering module 104, obtain new gain adjustment value through a low pass filter.

Yet owing to directly control said filter according to the intensity of output signal and the comparative result of threshold value, receive the performance impact of filter, the signal jitter amplitude of adjustment back output is bigger usually, causes more energy loss.Especially to based on CDMA technology with based on the GSM of OFDM/OFDMA technology; Its signal all has bigger peak-to-average force ratio; The fluctuation range broad, relatively more responsive to the shake of convergence, therefore use the said output signal of above-mentioned traditional DAGC system bigger signal fluctuation can occur.

For solving above-mentioned output signal with respect to the bigger problem of desired value fluctuation; Application number is digital auto gain control method and the system thereof that discloses a kind of communication system in 201010019389.6 the application documents; Mould value mean value through calculating said output signal or power average value are as the measured value of the intensity of said output signal; Therefore said measured value can reflect the intensity of said output signal more accurately, makes gain controlling more accurate; This method also is provided with the frequency of occurrences that a plurality of intensity statistics parameters add up respectively each strength grade in addition; Compare according to each said intensity statistics parameter and said parameter threshold value again; Decision yield value adjustment parameter; Undergo mutation because of output emergent indivedual high strength of signal or low-intensity distortion thereby prevent yield value, avoid exporting signal and excessive fluctuation occurs with respect to desired value.

Though the digital auto gain control method and the system thereof of above-mentioned a kind of communication system have plurality of advantages; But in the hardware implementation procedure, still found some defectives, for example said method can not be well with the power stability of exporting behind the cut position in a scope.

Summary of the invention

For addressing the above problem, the present invention provides a kind of digital auto gain control method and system, can be with output signal strength fluctuation control within the specific limits.

A kind of digital auto gain control method is characterized in that, may further comprise the steps:

Cut position is exported signal feedback return to carry out power statistic, obtain average power content;

Said average power content and preset strength grade parameter are compared, obtain corresponding step value and gain adjustment direction value;

According to said step value, gain adjustment direction value and preset initial yield value yield value is adjusted;

Adjusted yield value and input signal multiply by mutually carry out gain compensation, and the signal behind the gain compensation is carried out cut position output.

A kind of digital automatic gain control system is characterized in that, comprising:

The cut position output module is used for according to preset cut position bit wide and cut position position the signal behind the gain compensation being carried out exporting behind the cut position;

With the magnitude computation module that said cut position output module is connected, be used for the output signal feedback is returned to carry out power statistic, obtain average power content and send to amplitude grade comparison module;

The said amplitude grade comparison module that is connected with said magnitude computation module is used for said average power content and preset strength grade parameter are compared, and obtains corresponding step value and gain adjustment direction value;

With the gain value computation module that said amplitude grade comparison module is connected, be used for yield value being adjusted, and send to the yield value complementary module according to said step value, gain adjustment direction value and preset initial yield value;

The yield value complementary module that is connected with said gain value computation module is used for adjusted yield value and input signal multiply by mutually and carries out gain compensation, and the signal behind the gain compensation is sent to said cut position output module.

Can find out through above scheme; A kind of digital auto gain control method of the present invention and system; Through power statistics that the output signal feedback behind the cut position is returned, can better reflect the power rating of current output signal like this and output signal strength is fluctuateed control within the specific limits.

Description of drawings

Fig. 1 is the structural representation of traditional DAGC system;

Fig. 2 is the flow chart of a kind of digital auto gain control method of the present invention;

Fig. 3 realizes block diagram for sliding window statistics power;

Fig. 4 divides state diagram for threshold value;

The histogram distribution map of printout I road and Q circuit-switched data when Fig. 5 is input white Gaussian noise signal;

The histogram distribution map of printout I road and Q circuit-switched data when Fig. 6 is input CDMA2000 signal;

Fig. 7 is DAGC input pulse signal testing convergence time sketch map;

Fig. 8 is DAGC output pulse signal testing convergence time sketch map;

Fig. 9 is the structural representation of a kind of digital automatic gain control system of the present invention;

Figure 10 is the structural representation of a kind of digital automatic gain control system in the specific embodiment.

Embodiment

The present invention mainly is based on above-mentioned application " a kind of digital auto gain control method of communication system and system thereof " and its concrete execution mode is improved; Because find that in the hardware implementation procedure power stability that such scheme exports after can not be well with cut position is in a scope; Through finding why can have this problem after a large amount of tests; Be because such scheme adopts output signal before the cut position to calculate and as measured value to reflect the intensity of said output signal; Thereby brought bigger error, causing can't be with output signal strength fluctuation control within the specific limits.For this reason, the present invention provides a kind of digital auto gain control method and system, and can solve can't be with output signal strength fluctuation control problem within the specific limits in the technique scheme.Describe specific embodiment of the present invention in detail below in conjunction with accompanying drawing.

A kind of digital auto gain control method, as shown in Figure 2, comprise the steps:

Step S1; Strength grade parameter, counter steps value, initial gain, cut position position, cut position bit wide, gain maximum and gain minimum value etc. after powering on, system are set at first in advance; Then the output signal feedback behind the cut position is returned to carry out power statistic, obtain average power content.

For the power that guarantees to count on is linear change,, can use the mode of sliding window statistics to carry out power statistic as an embodiment preferably.Sliding window statistics power realizes that block diagram is as shown in Figure 3; Suppose that window length is set to L, with the input I, Q signal squared and, add up then (L+1) inferior value that obtains deducts first value when (L+1) is inferior to add up; Obtain the performance number of L point, should value can obtain average power content output again divided by L.The statistics power output can be expressed as as follows with mathematic(al) representation:

$\left\{\begin{array}{c}P\_\mathrm{out}=\frac{\left[\underset{k=n}{\overset{n+L+1}{\mathrm{\Σ}}}P\left(k\right)\right]-P(n-1)}{L},n=\mathrm{1,2,3}...\\ P\left(n\right)=I{\left(n\right)}^2+Q{\left(n\right)}^2,n=\mathrm{1,2,3}...\end{array}\right.$

In the formula, L is that window is long, I (n), I signal and the Q signal of Q (n) for importing, and P_out is said average power content.The present invention uses the mode of sliding window statistics power, can be good at reacting the variable power situation of output signal so that the statistical value that arrives is more level and smooth, and is more accurate to the control of back yield value.

Step S2 compares said average power content and preset strength grade parameter, obtains corresponding step value and gain adjustment direction value.

Above-mentioned comparing can be referring to the description in the application " a kind of digital auto gain control method of communication system and system thereof " with the process of gain adjustment direction value to obtain corresponding step value.Divide shown in the state diagram like threshold value among Fig. 4; The present invention is 5 values with the strength grade parameter setting; Each said strength grade is span of intensity of corresponding average power content all, comprises successively so that the signal strength signal intensity of its expression is descending: saturation condition, last state, stable state, following state and nought state.Wherein, what middle straight line threshold represented is threshold value, if the intensity of the average power content that statistics obtains equals said threshold value or only differs very little numerical value (m dB), then is stable (stablizing) state; If the intensity of said average power content is far longer than said threshold value and reaches certain numerical value (n dB), then is saturation (saturated) state; If the intensity of said average power content is far smaller than said threshold value and reaches certain numerical value (n dB), then is zero (zero) state; If the intensity of said average power content reaches certain numerical value (m dB), surpasses number range but the number range of no show saturation condition also of stable state greater than said threshold value, then be (above (on) state; If the intensity of said average power content reaches certain numerical value (m dB), surpasses the number range of stable state but the number range of no show nought state also then is below (a descending) state less than said threshold value.Above-mentioned m, n are the parameter that basis empirical value in the past is provided with, and can make amendment.

When the comparative result of said average power content drops on above-mentioned each state, start corresponding counter respectively and add 1, not when its corresponding state then counter subtract 1.After the individual count device reaches set point exportable corresponding step value D and gain adjustment direction value S.Need to prove that except that the stable state, the count value of other states all can have a protection value MAX, prevents to get into next state at once from preceding state, causes the cataclysm of gain curve.

Adopt above-mentioned method; Adjust with preset counter steps value according to strength grade scope that said average power content fell into and can obtain corresponding step value; The stable state of D value directly relatively obtains according to average power content and threshold value; Priority is the highest, and other states obtain according to the front Counter Value.The S value can be directly relatively obtain according to performance number and preset threshold value in real time in addition, and when said average power content during less than said threshold value, gain is to becoming big direction adjustment, and S gets 1; When said average power content during greater than said threshold value, gain is to the direction adjustment that diminishes, and S gets 0.The D value is predeterminable and adjustment at the calculator step value of each strength grade scope, obtains the D value S value correspondence line output of going forward side by side one by one like this.

Because the present invention only need judge big or small both direction when calculating D value and S value, so hardware is realized simply having simplified the hardware implementation complexity.

Step S3 adjusts yield value according to said step value, gain adjustment direction value and preset initial yield value.This step can use the mode of shifter-adder to realize, hardware is realized fairly simple quick:

When the S value of input was 1, the output gain value was the last yield value after last yield value adds the D position that moves to right;

When input S value was 0, the output gain value was the last yield value after last yield value deducts the D position that moves to right.

To guarantee also that in addition yield value must be in gain maximum that is provided with in advance and gain minimum value, when then exporting preset gain maximum or gain minimum value greater than maximum or less than minimum value.

Step S4 multiply by adjusted yield value and input signal mutually and to carry out gain compensation, and the signal behind the gain compensation is carried out cut position output.

As an embodiment preferably; Whether operate as normal is adjusted the strength grade parameter, output signal strength is fluctuateed control better within limits with better reference for checking system; And can change convergence time through the manual adjustment parameter; A kind of digital auto gain control method of the present invention, said signal behind the gain compensation is carried out cut position output after, can also comprise following step:

Step S5, the number that I road and each numerical value of Q road occur in interior output of the statistics scheduled time signal.For example: the dateout bit wide is 4bit behind the cut position, several 0,1,2,3,4,5,6,7,8,9, a that adds up respectively that 4bit hexadecimal can represent, b, c, d, e, f in totally 16 numerical value each numerical value report in predetermined number and the storage preparation that occurs in during this period of time.Wherein 0,1,2,3,4,5,6,7,8,9, a, b, c, d, e, f represent the IX/QX:0.5,1.5,2.5,3.5,4.5,5.5,6.5,7.5 ,-7.5 ,-6.5 ,-5.5 ,-4.5 ,-3.5 ,-2.5 ,-1.5 ,-0.5 of signed number respectively.

Step S6; Number according to said each numerical value occurs is calculated the probability P I-8PI-7PI-6 of I road and each numerical value appearance of Q road ... PI0PI1 ... PI6PI7 and PQ-8 PQ-7PQ-6 ... PQ0PQ1 ... PQ6PQ7; And, can adopt following formula according to the average power on I road and Q road in the said scheduled time of said probability calculation:

$\mathrm{Io}\_I=\underset{X=0}{\overset{15}{\mathrm{\Σ}}}(\mathrm{IX}^2*\mathrm{PIX});$

$\mathrm{Io}\_Q=\underset{X=0}{\overset{15}{\mathrm{\Σ}}}(\mathrm{QX}^2*\mathrm{PQX}).$

Need to prove that the difference of " average power content " among " average power " in this step and the step S1 is: the former " on average " time is long, and the latter's " on average " time is relatively short.

Step S7 prints demonstration with the average power that calculates, and adjusts said strength grade parameter according to this average power, till satisfying system requirements.Preferably, histogram data and the printout that can calculate I road and Q road are to judge whether DAGC output signal satisfies system requirements.The histogram distribution map of printout Q circuit-switched data when being illustrated in figure 5 as input white Gaussian noise signal; The histogram distribution map of printout Q circuit-switched data when Fig. 6 is input CDMA2000 signal; The different characteristic signal; The histogram data of output distribute can be different, and for the white Gaussian noise signal of input, each numerical value probability of occurrence of output 4bit data satisfies the Gaussian distribution situation.

Added above-mentioned three steps DAGC method afterwards, can the assist in debugging personnel when system debug, monitor current system mode in real time, and reach the purpose of optimization system index through modification to threshold values.

In addition,, can worsen the demodulation performance of system, so, require the convergence time of output signal to guarantee in the some very little time (in 1ms) usually in order to guarantee the demodulation performance of system if the convergence signal time is slow excessively.Therefore, whether digital auto gain control method of the present invention can also comprise a step of testing convergence time, enough little to judge convergence time.For the test of convergence time, existing technology is to judge convergence time in simulation stage through the change curve of observing yield value.And in real system because input/output signal can receive the influence of hardware in various degree, so the actual test of in hardware, carrying out convergence time can better be reacted the convergence time state of current system.The system detection method of convergence time of the present invention is: input pulse (Pulse) signal, and record output pulse is carved into stable blanking time constantly when changing, with this time as convergence time.As shown in Figure 7, input pulse width is the pulse signal (X2 point to the time interval that mark1 is ordered) of 10ms in this test, the minimum and maximum power difference 20dBm of input signal; Behind signal process DAGC; As shown in Figure 8; The output signal changes constantly through the of short duration sudden change constant power point that can stabilize in signal gain; Test DAGC output pulse is carved into when changing in time of sign mutation and is convergence time stable blanking time constantly, and through the value that frequency spectrograph can read convergence time (X2 point to the time interval that mark1 is ordered) is set, Δ Mark1 in the upper right corner can show that the convergence time of native system is about 644us on the frequency spectrograph.

Utilize above-mentioned method of testing, variation that can the Real Time Observation convergence time then can be adjusted convergence time through the adjustment parameter configuration when finding that convergence time is crossed slowly, up to satisfying system requirements.So just avoid the deterioration of system's demodulation performance, guaranteed the demodulation performance of system.

Can find out by above scheme; A kind of digital auto gain control method of the present invention; Cut position is exported signal feedback to be returned to carry out power statistic, the power that counts on is compared, produces new yield value according to comparative result; Then next supplied with digital signal is carried out gain controlling, last cut position output.Through power statistics that the output signal feedback behind the cut position is returned, can better reflect the power rating of current output signal like this and output signal strength is fluctuateed control within the specific limits; And method of the present invention directly does magnitude relatively with range value in systematic realizing program, saved the hardware cost of rated output and simplified the hardware implementation complexity.

Corresponding with a kind of digital auto gain control method of the present invention, the present invention also provides a kind of digital automatic gain control system, and is as shown in Figure 9, comprising:

The cut position output module is used for according to preset cut position bit wide and cut position position the signal behind the gain compensation being carried out exporting behind the cut position;

With the magnitude computation module that said cut position output module is connected, be used for the output signal feedback is returned to carry out power statistic, obtain average power content and send to amplitude grade comparison module;

The said amplitude grade comparison module that is connected with said magnitude computation module is used for said average power content and preset strength grade parameter are compared, and obtains corresponding step value and gain adjustment direction value;

With the gain value computation module that said amplitude grade comparison module is connected, be used for yield value being adjusted, and send to the yield value complementary module according to said step value, gain adjustment direction value and preset initial yield value;

The yield value complementary module that is connected with said gain value computation module is used for adjusted yield value and input signal multiply by mutually and carries out gain compensation, and the signal behind the gain compensation is sent to said cut position output module.

Whether operate as normal is adjusted the strength grade parameter, output signal strength is fluctuateed control better within limits with better reference for checking system; And can change convergence time through the manual adjustment parameter; As an embodiment preferably; Shown in figure 10, system of the present invention can also comprise:

With the numerical statistic module that said cut position output module is connected, be used for adding up the number that each numerical value of output signal occurs in the scheduled time;

With the data analysis module that said numerical statistic module is connected, be used for calculating the probability that each numerical value occurs according to the number that said each numerical value occurs, and according to the average power in the said scheduled time of said probability calculation;

With the printing display module that said data analysis module, amplitude grade comparison module are connected respectively, be used for the average power that said data analysis module calculates is printed demonstration and sends to said amplitude grade comparison module; Said amplitude grade comparison module is adjusted said strength grade parameter according to the average power that calculates in the said printing display module, till satisfying system requirements.

Native system has increased after numerical statistic module, data analysis module and the printing display module, can the assist in debugging personnel when system debug, monitor current system mode in real time, and reach the purpose of optimization system index through the modification to threshold values.

For the power that guarantees to count on is linear change, said magnitude computation module can use the mode of sliding window statistics to carry out power statistic, adopts following formula:

$\left\{\begin{array}{c}P\_\mathrm{out}=\frac{\left[\underset{k=n}{\overset{n+L+1}{\mathrm{\Σ}}}P\left(k\right)\right]-P(n-1)}{L},n=\mathrm{1,2,3}...\\ P\left(n\right)=I{\left(n\right)}^2+Q{\left(n\right)}^2,n=\mathrm{1,2,3}...\end{array}\right.$

In the formula, L is that window is long, I (n), I signal and the Q signal of Q (n) for importing, and P_out is said average power content.Use the mode of sliding window statistics power, can be good at reacting the variable power situation of output signal so that the statistical value that arrives is more level and smooth, more accurate to the control of back yield value.

Preferably; In order to guarantee the demodulation performance of system; Native system can also comprise the test module that is connected with said cut position output module, is used for to said cut position output module input pulse signal, and writes down to be carved into when exporting pulse by variation and stablize blanking time constantly as convergence time.Utilize the variation that this test module can the Real Time Observation convergence time, if find that convergence time is excessive then can adjust convergence time, up to satisfying system requirements through the adjustment parameter configuration.So just avoid the deterioration of system's demodulation performance, guaranteed the demodulation performance of system.

Preferably, said amplitude grade comparison module can comprise step value computing module and direction value computing module;

Strength grade scope that said step value computing module is used for falling into according to said average power content and counter steps value are adjusted and are obtained corresponding step value;

Said direction value computing module is used for preset threshold value, when said average power content less than said threshold value, then gain to becoming big direction adjustment, S=1; When said average power content greater than threshold value, then gain to the adjustment of the direction that diminishes, S=0.

Need to prove that calculated step value D and gain adjustment direction value S can also adopt additive method to carry out, as obtain step value D and gain adjustment direction value S through the method in the application " a kind of digital auto gain control method of communication system and system thereof ".But with above-mentioned application documents ratio, because the present invention only need judge big or small both direction when calculating D value and S value, so hardware is realized simply having simplified the hardware implementation complexity.

The other technologies characteristic of a kind of digital automatic gain control system of the present invention is identical with the description in above-mentioned a kind of digital auto gain control method, does not repeat them here.

A kind of digital automatic gain control system of the present invention; Cut position is exported signal feedback to be returned to carry out power statistic, the power that counts on is compared, produces new yield value according to comparative result; Then next supplied with digital signal is carried out gain controlling, last cut position output.Through power statistics that the output signal feedback behind the cut position is returned, can better reflect the power rating of current output signal like this and output signal strength is fluctuateed control within the specific limits; And system of the present invention directly does magnitude relatively with range value in systematic realizing program, saved the hardware cost of rated output and simplified the hardware implementation complexity.

Above-described embodiment of the present invention does not constitute the qualification to protection range of the present invention.Any modification of within spirit of the present invention and principle, being done, be equal to replacement and improvement etc., all should be included within the claim protection range of the present invention.

Claims (10)

1. a digital auto gain control method is characterized in that, may further comprise the steps:

Cut position is exported signal feedback return to carry out power statistic, obtain average power content;

Said average power content and preset strength grade parameter are compared, obtain corresponding step value and gain adjustment direction value;

According to said step value, gain adjustment direction value and preset initial yield value yield value is adjusted;

Adjusted yield value and input signal multiply by mutually carry out gain compensation, and the signal behind the gain compensation is carried out cut position output.

2. digital auto gain control method according to claim 1 is characterized in that, said signal behind the gain compensation is carried out also comprising step after the cut position output:

The number that each numerical value occurs in the output signal in the statistics scheduled time;

Number according to said each numerical value occurs is calculated the probability that each numerical value occurs, and according to the average power in the said scheduled time of said probability calculation;

The average power that calculates is printed demonstration, and adjust said strength grade parameter according to this average power.

3. digital auto gain control method according to claim 1 and 2 is characterized in that, said process of carrying out power statistic specifically comprises: use the mode of sliding window statistics to carry out power statistic, adopt following formula:

$\left\{\begin{array}{c}P\_\mathrm{out}=\frac{\left[\underset{k=n}{\overset{n+L+1}{\mathrm{\Σ}}}P\left(k\right)\right]-P(n-1)}{L},n=\mathrm{1,2,3}...\\ P\left(n\right)=I{\left(n\right)}^2+Q{\left(n\right)}^2,n=\mathrm{1,2,3}...\end{array}\right.$

In the formula, L is that window is long, I (n), I signal and the Q signal of Q (n) for importing, and P_out is said average power content.

4. digital auto gain control method according to claim 1 and 2 is characterized in that, also comprises step: the input pulse signal, and write down to be carved into when exporting pulse by variation and stablize blanking time constantly as convergence time.

5. digital auto gain control method according to claim 1 and 2 is characterized in that, said said average power content and preset strength grade parameter is compared, and the process that obtains corresponding step value and gain adjustment direction value specifically comprises:

Adjust with preset counter steps value according to strength grade scope that said average power content fell into and to obtain corresponding step value;

Preset threshold value, when said average power content less than said threshold value, then gain to becoming big direction adjustment, S=1; When said average power content greater than threshold value, then gain to the adjustment of the direction that diminishes, S=0;

Said step value is corresponding one by one with said gain adjustment direction value.

6. a digital automatic gain control system is characterized in that, comprising:

The cut position output module is used for according to preset cut position bit wide and cut position position the signal behind the gain compensation being carried out exporting behind the cut position;

With the magnitude computation module that said cut position output module is connected, be used for the output signal feedback is returned to carry out power statistic, obtain average power content and send to amplitude grade comparison module;

The said amplitude grade comparison module that is connected with said magnitude computation module is used for said average power content and preset strength grade parameter are compared, and obtains corresponding step value and gain adjustment direction value;

With the gain value computation module that said amplitude grade comparison module is connected, be used for yield value being adjusted, and send to the yield value complementary module according to said step value, gain adjustment direction value and preset initial yield value;

The yield value complementary module that is connected with said gain value computation module is used for adjusted yield value and input signal multiply by mutually and carries out gain compensation, and the signal behind the gain compensation is sent to said cut position output module.

7. digital automatic gain control system according to claim 6 is characterized in that, also comprises:

With the numerical statistic module that said cut position output module is connected, be used for adding up the number that each numerical value of output signal occurs in the scheduled time;

With the data analysis module that said numerical statistic module is connected, be used for calculating the probability that each numerical value occurs according to the number that said each numerical value occurs, and according to the average power in the said scheduled time of said probability calculation;

With the printing display module that said data analysis module, amplitude grade comparison module are connected respectively, be used for the average power that said data analysis module calculates is printed demonstration and sends to said amplitude grade comparison module; Said amplitude grade comparison module is adjusted said strength grade parameter according to the average power that calculates in the said printing display module.

8. according to claim 6 or 7 described digital automatic gain control systems, it is characterized in that said magnitude computation module uses the mode of sliding window statistics to carry out power statistic, adopts following formula:

$\left\{\begin{array}{c}P\_\mathrm{out}=\frac{\left[\underset{k=n}{\overset{n+L+1}{\mathrm{\Σ}}}P\left(k\right)\right]-P(n-1)}{L},n=\mathrm{1,2,3}...\\ P\left(n\right)=I{\left(n\right)}^2+Q{\left(n\right)}^2,n=\mathrm{1,2,3}...\end{array}\right.$

In the formula, L is that window is long, I (n), I signal and the Q signal of Q (n) for importing, and P_out is said average power content.

9. according to claim 6 or 7 described digital automatic gain control systems; It is characterized in that; Also comprise the test module that is connected with said cut position output module; Be used for to said cut position output module input pulse signal, and write down to be carved into when exporting pulse and stablize blanking time constantly as convergence time by variation.

10. according to claim 6 or 7 described digital automatic gain control systems, it is characterized in that said amplitude grade comparison module comprises step value computing module and direction value computing module;

Strength grade scope that said step value computing module is used for falling into according to said average power content and counter steps value are adjusted and are obtained corresponding step value;

Said direction value computing module is used for preset threshold value, when said average power content less than said threshold value, then gain to becoming big direction adjustment, S=1; When said average power content greater than threshold value, then gain to the adjustment of the direction that diminishes, S=0.

Images