CN102651636A - Peak counting method of automatic gain control loop - Google Patents

Abstract

The invention discloses a peak counting method of an automatic gain control loop. The method comprises the following steps: step 1, according to the probability density function of a sound sine signal, determining a probability formula of the sound sine signal positioned in a certain signal amplitude range; step 2, according to a best signal amplitude value range, determining the accurate probability value of the sound signal positioned in the amplitude range; step 3, according to the characteristics of the accurate probability value of the signal, determining signal points needing to be sampled in the effective judgment to a signal peak; and step 4, finally according to the digital counting characteristics of the minimum signal points, making a digital logic judgment and transmitting the result of the judgment to a variable gain amplifier in the automatic gain control loop. The method can be applied to the automatic gain control loop of a hearing aid with a digital-analog hybrid structure, a control logic algorithm is simplified, the hardware cost of digital modules is reduced, and gain of the automatic gain control loop can be accurately and effectively controlled.

Description

A kind of peak value statistical method of automatic gain control loop

Technical field

The present invention relates to CMOS mixed-signal designs technical field, be specifically related to a kind of peak value statistical method of automatic gain control loop.

Background technology

Automatic gain control loop is the closed-loop system that is made up of variable gain amplifier and negative feedback control loop.Automatic gain control loop is widely used among hearing aids, disk drive circuit and the nearly all radio communication circuit.The core of automatic gain control loop is the digital control logic circuit of realizing with full custom design technology, and rational algorithm logic can effectively reduce the power consumption and the expense of digital circuit, is to determine an automatic gain control loop key of success.The peak value algorithm logic of extensive use at present is normally with the peak value of the single point signals distinguishing rule as the ride gain loop.Because sound is a multi-frequency, the aperiodicity signal that the amplitude rapid Continuous changes if sampling single point signals peak value is adjudicated, is prone to cause the misoperation of automatic gain control loop.Therefore have only voice signal is carried out mathematical statistics, extract the statistical characteristic of one section voice signal, could adjudicate, accomplish high-precision loop gain control according to it.

The present invention proposes a kind of peak value statistic logic algorithm of using based on the hearing aids automatic gain control loop, to satisfy the system requirements of high accuracy, configurable, low power consumption digital hearing aids.

Summary of the invention

The technical problem that (one) will solve

In view of this; The problem that the present invention will solve provides a kind of peak value statistical method of automatic gain control loop; When being applied to the hearing aids automatic gain control loop to solve traditional single-point differentiation peak value algorithm logic; The problem that control precision is not high reaches the purpose that High Precision Automatic gain control loop is controlled.

(2) technical scheme

For achieving the above object, the invention provides a kind of peak value statistical method of automatic gain control loop, comprising:

Step 1, according to the probability density function of sound sinusoidal signal, confirm that the sound sinusoidal signal is positioned at the new probability formula of certain signal amplitude scope;

Step 2, according to optimum signal range value scope, confirm that voice signal is positioned at the accurate probable value of this amplitude range;

Step 3, according to voice signal characteristic and accurate probable value, confirm that the signal of signal peak effectively being adjudicated required sampling counts;

Step 4, the statistics property characteristic of finally counting according to minimum signal are made the Digital Logic judgement, feed back to the variable gain amplifier in the automatic gain control loop.

In the such scheme, said step 1 specifically comprises: step 11, to establish voice signal be sinusoidal signal: V=Asin ω t; According to the sinusoidal wave probability density function of random phase; Then its probability density that is positioned at a certain voltage Vx place is:

wherein V is sinusoidal signal; A is the amplitude of sinusoidal signal; ω is the angular frequency of sinusoidal signal; T is any some coordinates on the time shaft, and x is any some coordinates on the voltage axis.Step 12, according to formula (1), a voice signal drops on (V _a, V _b) between probability be: $p(V_a,V_b)={\&Integral;}_{V_a}^{{\mathrm{<figure-callout\; id="1"\; label="V\; b"\; filenames="HDA0000157529540000021.png"\; state="\{\{state\}\}">V</figure-callout>}}_b}\frac{1}{\mathrm{\&pi;}\sqrt{A^2-{V_x}^2}}d{V}_x=\frac{1}{\mathrm{\&pi;}}[{\mathrm{Sin}}^{-1}\left(\frac{V_b}{A}\right)-{\mathrm{Sin}}^{-1}\left(\frac{V_a}{A}\right)]---\left(2\right);$ Step 13, cosine function cos is got on formula (2) both sides, and according to Obtain:

$V_b^2-\left(2V_a\cos \left(\mathrm{\&pi;P}(V_a,V_b)\right)\right)V_b-A^2(1-{\cos }^2\left(\mathrm{\&pi;P}(V_a,V_b)\right))+V_a^2=0---\left(3\right).$

In the such scheme, said step 2 specifically comprises: step 21, the supply voltage of establishing this automatic gain control loop are VDD, and then the optimum range scope of voice signal does

Between; Step 22, according to step 21, will

In the formula of substitution step 13 (3), can obtain cos (π P (V _a, V _b)) ≈ 0.94188; Step 23, therefore according to the result of calculation of step 22, behind the negate cosine function, calculate signal and drop on

Between probability be P (V _a, V _b) ≈ 0.1091.

In the such scheme; Said step 3 specifically comprises: the sampled point in one period complete at least 600 cycle of voice signal needs; Therefore the probable value that draws according to step 23; Calculating needs 600 * 0.1091 ≈ 65.4 at least; Promptly the statistical property of 66 above sampled points could judge whether this voice signal drops between

.

In the such scheme; Said step 4 specifically comprises: according to the result of calculation of step 3; In 600 sampled points of each sampling; When being Digital Logic comparison upper limit threshold level with

, 600-66=534 Digital Logic " 0 " appears at least; And be Digital Logic relatively during the lower threshold level with

, occur 66 Digital Logic " 1 " at least and could adjudicate this signal and drop between .

(3) beneficial effect

Compared with prior art, the beneficial effect of technical scheme generation of the present invention is following:

The present invention draws the accurate probability that signal is positioned at the optimum reception scope through adopting the algorithm of probability density; And according to the characteristics of voice signal, and then draw the minimum sampling number of automatic gain control loop accurately being controlled required signal, finally draw the statistical information of this part sampled point; Form judgement; Export correct digital control sign indicating number, algorithm is simple, when digital circuit realizes, has effectively reduced circuit overhead and power consumption; Be applicable to low-power consumption, in the High Precision Automatic gain control loop.

Description of drawings

Fig. 1 is the flow chart according to the peak value statistical method of the automatic gain control loop of the embodiment of the invention;

Fig. 2 is the signal graph according to the actual sound of the embodiment of the invention;

Fig. 3 is the sketch map that detects principle according to the peak value of the embodiment of the invention;

Fig. 4 is the circuit diagram according to the automatic gain control loop of the embodiment of the invention;

Fig. 5 is according to being applied in the automatic gain control loop of the embodiment of the invention, under the 10KHZ frequency, and the output waveform of input 5mV sinusoidal signal.

Embodiment

For making the object of the invention, technical scheme and advantage clearer, below in conjunction with specific embodiment, and with reference to accompanying drawing, to further explain of the present invention.

As shown in Figure 1, Fig. 1 is that this method comprises according to the flow chart of the peak value statistical method of the automatic gain control loop of the embodiment of the invention:

Step 1, according to the probability density function of sound sinusoidal signal, confirm that the sound sinusoidal signal is positioned at the new probability formula of certain signal amplitude scope;

Step 2, according to optimum signal range value scope, confirm that voice signal is positioned at the accurate probable value of this amplitude range;

Step 3, according to voice signal characteristic and accurate probable value, confirm that the signal of signal peak effectively being adjudicated required sampling counts;

Step 4, the statistics property characteristic of finally counting according to minimum signal are made the Digital Logic judgement, feed back to the variable gain amplifier in the automatic gain control loop.

Wherein, said step 1 specifically comprises:

Step 11, to establish voice signal be sinusoidal signal: V=Asin ω t; According to the sinusoidal wave probability density function of random phase, then it is positioned at a certain voltage V _xThe probability density at place is:

Wherein V is a sinusoidal signal, and A is the amplitude of sinusoidal signal, and ω is the angular frequency of sinusoidal signal, and t is any some coordinates on the time shaft, and x is any some coordinates on the voltage axis;

Step 12, according to formula (1), a voice signal drops on (V _a, V _b) between probability be:

$p(V_a,V_b)={\&Integral;}_{V_a}^{{\mathrm{<figure-callout\; id="1"\; label="V\; b"\; filenames="HDA0000157529540000021.png"\; state="\{\{state\}\}">V</figure-callout>}}_b}\frac{1}{\mathrm{\&pi;}\sqrt{A^2-{V_x}^2}}d{V}_x=\frac{1}{\mathrm{\&pi;}}[{\sin }^{-1}\left(\frac{V_b}{A}\right)-{\sin }^{-1}\left(\frac{V_a}{A}\right)]---\left(2\right);$

Step 13, cosine function cos is got on formula (2) both sides, and according to $\mathrm{Cos}\left({\mathrm{Sin}}^{-1}\left(\frac{V_x}{A}\right)\right)=\frac{\sqrt{A^2-{V_x}^2}}{A},$ Obtain:

$V_b^2-\left(2V_a\cos \left(\mathrm{\&pi;P}(V_a,V_b)\right)\right)V_b-A^2(1-{\cos }^2\left(\mathrm{\&pi;P}(V_a,V_b)\right))+V_a^2=0---\left(3\right).$

Wherein, said step 2 specifically comprises:

Step 21, the supply voltage of establishing this automatic gain control loop are VDD, and then the optimum range scope of voice signal is between

;

Step 22, according to step 21, will

In the formula of substitution step 13 (3), can obtain cos (π P (V _a, V _b)) ≈ 0.94188;

Step 23, therefore according to the result of calculation of step 22, behind the negate cosine function, calculate signal and drop on

Between probability be P (V _a, V _b) ≈ 0.1091.

In the such scheme; Said step 3 specifically comprises: the sampled point in one period complete at least 600 cycle of voice signal needs; Therefore the probable value that draws according to step 23; Calculating needs 600 * 0.1091 ≈ 65.4 at least; Promptly the statistical property of 66 above sampled points could judge whether this voice signal drops between .

Wherein, Said step 4 specifically comprises: according to the result of calculation of step 3; In 600 sampled points of each sampling; When being Digital Logic comparison upper limit threshold level with

, 600-66=534 Digital Logic " 0 " appears at least; And be Digital Logic relatively during the lower threshold level with , occur 66 Digital Logic " 1 " at least and could adjudicate this signal and drop between

.

Based on method flow diagram shown in Figure 1, Fig. 2 shows the signal graph according to the actual sound of the embodiment of the invention.Real sound is the sinusoidal wave combination of multi-frequency aperiodicity, and because volume is different, corresponding signal amplitude is also inequality.Therefore voice signal is carried out rational gain controlling, just need to extract the statistical characteristic of one section voice signal, could adjudicate, accomplish loop gain control according to it.

Referring to Fig. 3; Fig. 3 is the sketch map that detects principle according to the peak value of the embodiment of the invention, and basic principle of the present invention is: when the signal peak of signal in greater than compare threshold Vref1 the time, because the sampling clock frequency is much larger than the voice signal frequency; Even the peak value of signal is greater than compare threshold Vref1 at this moment; Still therefore the situation that has " 1 " and " 0 " coexistence in the digital code of sampling output has only the sequence as a result of continuous output is done mathematical statistics, just when the sampling number of output output " 1 " is counted greater than the minimum under the statistical probability; Just can think the in signal peak greater than Vref1, the statistical property logic is just exported " 1 "; With should output the sampling number of output " 1 " when counting less than the minimum under the statistical probability, can think during this period of time the in signal peak less than Vref1, statistical property logic output " 0 ".

According to above-mentioned steps 1, step 2, step 3 and step 4, can proper sampled point be 600 o'clock, then need the output digital code " 1 " more than 66 at least, ability decision signal peak value is greater than compare threshold Vref1.Fig. 4 is the automatic gain control loop circuit diagram that adopts peak value statistic logic algorithm to realize in the embodiment of the invention.Fig. 5 is in the automatic gain control loop, under the 10KHZ frequency, and the output waveform of input 5mV sinusoidal signal, technique effect is good.

In sum, the peak value statistical method of automatic gain control loop provided by the invention has following beneficial effect: (1) the present invention draws the accurate probability that voice signal is positioned at the optimum reception scope through adopting the algorithm of probability density; (2), and then draw the minimum sampling number of automatic gain control loop accurately being controlled required signal according to the characteristics of voice signal; (3) according to the statistical information of this part sampled point, form judgement, export correct digital control sign indicating number; (4) algorithm of the present invention is simple, when digital circuit realizes, has effectively reduced circuit overhead and power consumption, is applicable to low-power consumption, in the High Precision Automatic gain control loop.

Above-described specific embodiment; The object of the invention, technical scheme and beneficial effect have been carried out further explain, and institute it should be understood that the above is merely specific embodiment of the present invention; Be not limited to the present invention; All within spirit of the present invention and principle, any modification of being made, be equal to replacement, improvement etc., all should be included within protection scope of the present invention.

Claims (5)

1. the peak value statistical method of an automatic gain control loop is characterized in that, comprising:

Step 1, according to the probability density function of sound sinusoidal signal, confirm that the sound sinusoidal signal is positioned at the new probability formula of certain signal amplitude scope;

Step 2, according to optimum signal range value scope, confirm that voice signal is positioned at the accurate probable value of this amplitude range;

Step 3, according to voice signal characteristic and accurate probable value, confirm that the signal of signal peak effectively being adjudicated required sampling counts;

Step 4, the statistics property characteristic of finally counting according to minimum signal are made the Digital Logic judgement, feed back to the variable gain amplifier in the automatic gain control loop.

2. the peak value statistical method of automatic gain control loop according to claim 1 is characterized in that, said step 1 specifically comprises:

Step 11, to establish voice signal be sinusoidal signal: V=Asin ω t; According to the sinusoidal wave probability density function of random phase, then it is positioned at a certain voltage V _xThe probability density at place is:

Wherein V is a sinusoidal signal, and A is the amplitude of sinusoidal signal, and ω is the angular frequency of sinusoidal signal, and t is any some coordinates on the time shaft, and x is any some coordinates on the voltage axis;

Step 12, according to formula (1), a voice signal drops on (V _a, V _b) between probability be:

Step 13, cosine function cos is got on formula (2) both sides, and obtains according to :

3. the peak value statistical method of automatic gain control loop according to claim 2 is characterized in that, said step 2 specifically comprises:

Step 21, the supply voltage of establishing this automatic gain control loop are VDD, and then the optimum range scope of voice signal is between ;

Step 22, according to step 21, will

In the formula of substitution step 13 (3), can obtain cos (π P (V _a, V _b)) ≈ 0.94188;

Step 23, therefore according to the result of calculation of step 22, behind the negate cosine function, calculate signal and drop on

Between probability be P (V _a, V _b) ≈ 0.1091.

4. the peak value statistical method of automatic gain control loop according to claim 2 is characterized in that, said step 3 specifically comprises:

One section complete voice signal needs the sampled point at least 600 cycles; Therefore the probable value that draws according to step 23; Calculating needs 600 * 0.1091 ≈ 65.4 at least; Promptly the statistical property of 66 above sampled points could judge whether this voice signal drops between

.

5. the peak value statistical method of automatic gain control loop according to claim 4 is characterized in that, said step 4 specifically comprises:

Result of calculation according to step 3; In 600 sampled points of each sampling; When being Digital Logic comparison upper limit threshold level with

, 600-66=534 Digital Logic " 0 " appears at least; And be Digital Logic relatively during the lower threshold level with

, occur 66 Digital Logic " 1 " at least and could adjudicate this signal and drop between

.

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