CN203747761U - Automatic gain adjustment circuit - Google Patents
Automatic gain adjustment circuit Download PDFInfo
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- CN203747761U CN203747761U CN201420026097.9U CN201420026097U CN203747761U CN 203747761 U CN203747761 U CN 203747761U CN 201420026097 U CN201420026097 U CN 201420026097U CN 203747761 U CN203747761 U CN 203747761U
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Abstract
The utility model discloses an automatic gain adjustment circuit. The automatic gain adjustment circuit comprises a variable gain amplification circuit, a comparison voltage generation circuit and a signal detection circuit, wherein the variable gain amplification circuit receives voice signals input from the outside, amplifies the voice signals and outputs the amplified voice signals, the comparison voltage generation circuit generates a reference voltage and loads the reference voltage to the signal detection circuit, the signal detection circuit detects the deviation between the amplitude of the voice signals output after comparison and a set amplitude, and when the amplitude of the voice signals output by the variable gain amplification circuit deviates from the set amplitude, the signal detection circuit feeds a varied voltage back to the variable gain amplification circuit. The variable gain amplification circuit adjusts the amplitude of the voice signals output by the variable gain amplification circuit according to the varied voltage, and the amplitude of the voice signals output by the variable gain amplification circuit is made to be the same as the set amplitude. After the automatic gain adjustment circuit receives the voice signals output from the outside, a stable voice signal with the amplitude the same as the set amplitude is output, and the identification accuracy of the received voice signals is improved.
Description
Technical field
The utility model relates to field of speech recognition, relates more specifically to a kind of automatic gain adjusting circuit.
Background technology
In the time utilizing voice recognition chip to carry out speech recognition, be Protean as the position of the source of sound of signal source from the distance of voice recognition chip, and conventional speech recognition system is the amplification output that the voice signal of input is fixed to multiple; Just cause as following problems for the speech recognition system that adopts fixing multiplication factor like this: when the position of source of sound from speech recognition system very close to time, the voice signal amplitude detecting due to voice recognition chip is very large, after the amplifier of fixing multiple, will cause the slicing of output voice signal; But in the time that the position of source of sound is far from speech recognition system, because the amplitude of voice signal is along with the increase of distance forms index decreased, the signal amplitude after the amplifier of fixing multiplication factor is amplified is still very little, thereby is difficult to reach designing requirement.Therefore, the above accuracy of identification that affects speech recognition system that either way can be serious.
Therefore, be necessary to provide a kind of improved speech recognition system to overcome above-mentioned defect.
Utility model content
The purpose of this utility model is to provide a kind of automatic gain adjusting circuit, this circuit carries out identifying processing to voice signal, and after the voice signal within the scope of certain amplitude is received by automatic gain adjusting circuit of the present utility model, all can export a stable voice signal that amplitude is identical with setting amplitude, improve the accuracy of identification of the voice signal to receiving.
The purpose of this utility model is to provide a kind of automatic gain adjusting circuit, for regulating the output amplitude of voice signal, it comprises variable-gain amplification circuit, comparative voltage generative circuit and signal deteching circuit, described variable-gain amplification circuit receives the voice signal of outside input and the voice signal of input is amplified and exports the voice signal after amplification, described comparative voltage generative circuit is connected with described signal deteching circuit, be loaded on described signal deteching circuit to generate a reference voltage, and described reference voltage value is set according to the setting amplitude of output voice signal, described signal deteching circuit is connected with described variable-gain amplification circuit, described signal deteching circuit detects the amplitude of the voice signal of described variable-gain amplification circuit output, and the deviation of the amplitude of the voice signal of more described output and the amplitude of setting, in the time that the amplitude of the voice signal of described variable-gain amplification circuit output departs from setting amplitude, the voltage of a variation of described signal deteching circuit feedback is to described variable-gain amplification circuit, and described variable-gain amplification circuit is adjusted the amplitude of its output voice signal according to the voltage of this variation, so that the amplitude of the voice signal of described variable-gain amplification circuit output is identical with setting amplitude.
Preferably, described variable-gain amplification circuit comprises amplifier, feedback resistance, the first adjustable resistance electronic circuit and the second adjustable resistance electronic circuit, the two ends of described feedback resistance are connected with reverse input end and the output of described amplifier respectively, the positive input of described amplifier receives external sound signal, described the first adjustable resistance electronic circuit is connected with the reverse input end of described amplifier, described the second adjustable resistance electronic circuit is connected with the positive input of described amplifier, and outside common-mode voltage is inputted respectively described the first adjustable resistance electronic circuit and the second adjustable resistance electronic circuit, described the first adjustable resistance electronic circuit is all connected with the output of described signal deteching circuit with the second adjustable resistance electronic circuit.
Preferably, described the first adjustable resistance electronic circuit comprises the first field effect transistor and the first resistance, one end of the source electrode of described the first field effect transistor and the first resistance is all connected with outside common-mode voltage output, the other end of the drain electrode of described the first field effect transistor and the first resistance is all connected with the reverse input end of described amplifier, and the grid of described the first field effect transistor is connected with the output of described signal deteching circuit.
Preferably, described the first adjustable resistance electronic circuit and the second adjustable resistance electronic circuit have identical architectural feature.
Preferably, the resistance of the first resistance of described the second adjustable resistance electronic circuit equals the first resistance of described the first adjustable resistance electronic circuit resistance value after in parallel with feedback resistance.
Preferably, described signal deteching circuit comprises the second field effect transistor, the 3rd field effect transistor, the 4th field effect transistor, the 5th field effect transistor, the 6th field effect transistor, the second resistance and electric capacity, the grid of described the second field effect transistor is connected with the output of described variable-gain amplification circuit, and its source electrode is connected with described comparative voltage generative circuit, the drain electrode of the drain electrode of described the second field effect transistor and described the 3rd field effect transistor, the grid of grid and the 4th field effect transistor connects jointly, described the 3rd field effect transistor, the source electrode of the 4th field effect transistor and the 5th field effect transistor is all connected with external power source, the drain electrode of described the 4th field effect transistor, one end of the second resistance, the grid of one end of electric capacity and described the 6th field effect transistor connects jointly, and the drain electrode of described the 5th field effect transistor and the drain electrode of described the 6th field effect transistor are connected and form the output of described signal deteching circuit, the source electrode of described the 6th field effect transistor, the grid of the 5th field effect transistor, the other end of described the second resistance and the equal ground connection of the other end of described electric capacity.
Preferably, described comparative voltage generative circuit comprises the 3rd resistance, the 4th resistance and voltage follower, described the 3rd resistance one end is connected with external power source, the other end is connected with described the 4th one end of resistance and the positive input of described voltage follower, the other end ground connection of described the 4th resistance, the reverse input end of described voltage follower is connected with its output, and the output of described voltage follower is connected with described signal deteching circuit.
Compared with prior art, automatic gain adjusting circuit of the present utility model, because described signal deteching circuit detects the amplitude of the voice signal of described variable-gain amplification circuit output, and the deviation of the amplitude of the voice signal of more described output and the amplitude of setting, in the time that the amplitude of the voice signal of described variable-gain amplification circuit output departs from setting amplitude, the voltage of a variation of described signal deteching circuit feedback is to described variable-gain amplification circuit, and described variable-gain amplification circuit is adjusted the amplitude of its output voice signal according to the voltage of this variation, thereby after the external sound signal within the scope of certain amplitude is received by automatic increasing regulating circuit of the present utility model, after the amplification of described variable-gain amplification circuit and the regulating and controlling of described signal deteching circuit, all can export over time the stable voice signal that an amplitude is identical with setting amplitude, improve the accuracy of identification to voice signal.
By following description also by reference to the accompanying drawings, it is more clear that the utility model will become, and these accompanying drawings are used for explaining the utility model.
Brief description of the drawings
Fig. 1 is the circuit structure diagram of the utility model automatic gain adjusting circuit.
Embodiment
With reference now to accompanying drawing, describe embodiment of the present utility model, in accompanying drawing, similarly element numbers represents similar element.As mentioned above, the utility model provides a kind of automatic gain adjusting circuit, this circuit carries out identifying processing to voice signal, and after the voice signal within the scope of certain amplitude is received by automatic gain adjusting circuit of the present utility model, all can export a stable voice signal that amplitude is identical with setting amplitude, improve the accuracy of identification of the voice signal to receiving.
Please refer to Fig. 1, Fig. 1 is the circuit structure diagram of the utility model automatic gain adjusting circuit.Automatic gain adjusting circuit of the present utility model is for regulating the output amplitude of its voice signal receiving, and the setting amplitude of the voice signal of the stable output of setting the utility model automatic gain adjusting circuit is Vm.As shown in Figure 1, automatic gain adjusting circuit of the present utility model comprises variable-gain amplification circuit, comparative voltage generative circuit and signal deteching circuit, described variable-gain amplification circuit receives the voice signal Vin of outside input and this voice signal Vin amplification is exported to the voice signal VOUT after amplifying, described comparative voltage generative circuit is connected with described signal deteching circuit, is loaded on described signal deteching circuit to generate a reference voltage V c, and the value of described reference voltage V c is set according to the setting amplitude Vm of output voice signal, described signal deteching circuit is connected with described variable-gain amplification circuit, described signal deteching circuit detects the amplitude of the voice signal VOUT of described variable-gain amplification circuit output, and the deviation of the amplitude of the voice signal VOUT of more described output and the amplitude of setting Vm, in the time that the amplitude of the voice signal VOUT of described variable-gain amplification circuit output departs from setting amplitude Vm, the voltage Vg of a variation of described signal deteching circuit feedback is to described variable-gain amplification circuit, and described variable-gain amplification circuit is adjusted the amplitude of its output voice signal VOUT according to the voltage of this variation, so that the amplitude of the voice signal VOUT of described variable-gain amplification circuit output is identical with the amplitude of setting Vm.
Particularly, described variable-gain amplification circuit comprises amplifier OP1, feedback resistance Rf, the first adjustable resistance electronic circuit and the second adjustable resistance electronic circuit, the two ends of described feedback resistance Rf are connected with reverse input end and the output of described amplifier OP1 respectively, and the output of described amplifier OP1 is the output of described variable-gain amplification circuit, external sound signal Vin inputs the positive input of described amplifier, described the first adjustable resistance electronic circuit is connected with the reverse input end of described amplifier, thereby can be the gain multiple of adjustable described amplifier OP by regulating the equivalent resistance of described the first adjustable resistance electronic circuit and the resistance of feedback resistance Rf, described the second adjustable resistance electronic circuit is connected with the positive input of described amplifier, and outside common-mode voltage Vcm inputs respectively described the first adjustable resistance electronic circuit and the second adjustable resistance electronic circuit, described the first adjustable resistance electronic circuit is all connected with the output of described signal deteching circuit with the second adjustable resistance electronic circuit, and described signal deteching circuit output voltage V g is to described the first adjustable resistance electronic circuit and the second adjustable resistance electronic circuit, in preferred implementation of the present utility model, described the first adjustable resistance electronic circuit comprises the first field effect transistor MR1 and the first resistance R 1, one end of the source electrode of described the first field effect transistor MR1 and the first resistance R 1 is all connected with the output of outside common-mode voltage, with extremely described the first adjustable resistance electronic circuit of output common mode voltage Vcm, the other end of the drain electrode of described the first field effect transistor MR1 and the first resistance R 1 is all connected with the reverse input end of described amplifier OP1, described the first grid of field effect transistor MR1 and the output of described signal deteching circuit are connected, described signal deteching circuit output voltage V g is to the grid of described the first field effect transistor MR1.And in the utility model, described the first adjustable resistance electronic circuit and the second adjustable resistance electronic circuit have identical architectural feature, described the first adjustable resistance electronic circuit comprises the first field effect transistor MR1 ' and the first resistance R 1 ', and the resistance of the first resistance R 1 ' of described the second adjustable resistance electronic circuit equals the first resistance R 1 of described the first adjustable resistance electronic circuit resistance value after in parallel with feedback resistance Rf, be R1 '=R1//Rf, apparent, the structure of described the second adjustable resistance electronic circuit does not affect the gain of described amplifier OP1, by R1 '=R1//Rf is set, can reduce described amplifier OP1 imbalance in the course of the work this its, so that the output of described amplifier OP1 is more accurate, described second other architectural feature of adjustable resistance electronic circuit and function are all identical with the adjustable electronic circuit of described the first resistance, do not repeat them here.
Described signal deteching circuit comprises the second field effect transistor M2, the 3rd field effect transistor M3, the 4th field effect transistor M4, the 5th field effect transistor M5, the 6th field effect transistor M6, the second resistance R 2 and capacitor C 1, described the second grid of field effect transistor M2 and the output of described variable-gain amplification circuit (being the output of described amplifier OP1) are connected, its source electrode is connected with described comparative voltage generative circuit, thereby the voltage Vout of the output signal VOUT of described variable-gain amplification circuit inputs described signal deteching circuit by described the second field effect transistor M2, the drain electrode of the drain electrode of described the second field effect transistor M2 and described the 3rd field effect transistor M3, the grid of grid and the 4th field effect transistor M4 connects jointly, described the 3rd field effect transistor M3, the source electrode of the 4th field effect transistor M4 and the 5th field effect transistor M5 is all connected with external power source VDD, the drain electrode of described the 4th field effect transistor M4, one end of the second resistance R 2, the grid of one end of capacitor C 1 and described the 6th field effect transistor M6 connects jointly, described the 3rd field effect transistor M3 and the 4th field effect transistor M4 form mirror image circuit, thereby by the electric current I ds2 of described the second field effect transistor M2 that flows through in proportion mirror image be the electric current I ds4 of described the 4th field effect transistor M4 of flowing through, the drain electrode of described the 5th field effect transistor M5 and the drain electrode of described the 6th field effect transistor M6 are connected and form the output of described signal deteching circuit, and output voltage V g, and the magnitude of voltage of described voltage Vg will change according to the variation of voltage Vout value, the other end of the source electrode of described the 6th field effect transistor M6, the grid of the 5th field effect transistor M5, described the second resistance R 2 and the equal ground connection of the other end of described capacitor C 1.
Described comparative voltage generative circuit comprises the 3rd resistance R 3, the 4th resistance R 4 and voltage follower OP2, described the 3rd resistance R 3 one end are connected with external power source VDD, the other end is connected with one end of described the 4th resistance R 4 and the positive input of described voltage follower OP2, the other end ground connection of described the 4th resistance R 4, be that described the 3rd resistance R 3 and the 4th resistance R 4 are carried out dividing potential drop to supply voltage VDD, and obtain the voltage Vcomp of the positive input of described follower OP2; Thereby require to export while being set in circuit steady operation the setting amplitude Vm of voice signal according to circuit design, and according to this setting amplitude Vm, select the 3rd resistance R3 and the 4th resistance R 4 of suitable resistance and make the voltage Vcomp of the positive input of described voltage follower OP2 can be corresponding to the setting amplitude Vm that exports voice signal; The reverse input end of described voltage follower OP2 is connected with its output, and the output of described voltage follower OP2 is connected with described signal deteching circuit, be connected with the source electrode of described the second field effect transistor M2 particularly, make the voltage Vc of described voltage follower OP2 output can be used as reference voltage for described signal deteching circuit reference, and Vc=Vcomp, thereby described voltage Vc is corresponding to the amplitude of setting Vm; In addition, from the circuit structure of automatic gain adjusting circuit of the present utility model, in the time that circuit is normally worked, Vout=V
gs2+ V
c; And when circuit of the present utility model is in steady-working state, when the amplitude of described variable-gain amplification circuit output voice signal VOUT is setting amplitude Vm, Vout=V
m=V
gs2+ V
c, (V
gs2be the gate source voltage of the second field effect transistor M2), and in circuit design, make described the second field effect transistor M2 just be operated in subthreshold value state (how to make field effect transistor be operated in subthreshold value state and be well known to those skilled in the art, no longer carefully state at this), thus in the time of its conducting V
gs2≈ V
th2(V
th2be the threshold voltage of the second field effect transistor M2), Vout=V
m=V
th2+ V
cthereby can be also Vc by setting the input voltage Vcomp(of described comparative voltage generative circuit) value, in the time that the voice signal Vin of input is setting in adjustable extent, can make the amplitude of described output voice signal VOUT identical with the amplitude of setting Vm after adjustment after a while, to ensure the accuracy of identification to input speech signal.
Operation principle below in conjunction with describe the utility model automatic gain adjusting circuit with reference to figure 1:
The variable-gain amplification circuit of automatic gain adjusting circuit of the present utility model, due to R1 '=R1//Rf, thereby ensure that the impedance that is carried in amplifier OP1 Direct/Reverse input equates, the first field effect transistor MR1, MR1 ' are identical simultaneously, separately in the utility model, two first field effect transistor are all operated in triode region (being that drain-source voltage is less than overload voltage), and the output voltage V out of described variable-gain amplification circuit output voice signal VOUT is:
Wherein Rds1 is the equivalent resistance that is operated in triode region the first field effect transistor MR1, and its impedance is
Wherein μ
n, c
oxand (W/L)
1be respectively carrier mobility, gate oxide unit-area capacitance amount and the breadth length ratio of the first field effect transistor MR1.When after manufacturing process determination, μ
n, c
ox, V
th1for relatively constant amount, therefore only need the size that changes voltage Vg can change the resistance value of the equivalent resistance Rds1 of the first field effect transistor MR1, and change the gain multiple of described amplifier OP1, and then regulate the amplitude of described output voice signal VOUT; Wherein, in the time that the output voice signal VOUT of described variable-gain amplification circuit amplitude is greater than setting amplitude Vm, the output voltage V g of described signal deteching circuit reduces, it is large that the equiva lent impedance Rds1 of the first adjustable resistance electronic circuit becomes, from (1) formula, voltage Vout reduces, and exports voice signal VOUT amplitude and reduces; In addition, in the time that the amplitude of output voice signal VOU is less than setting amplitude Vm, the output voltage V g of described signal deteching circuit raises, and equiva lent impedance Rds1 diminishes, and from (1) formula, it is large that voltage Vout becomes, and exports voice signal VOUT amplitude and becomes large; Therefore, the voice signal Vin of different amplitudes that what automatic gain adjusting circuit of the present utility model can be received have, after described variable-gain amplification circuit and the adjusting of signal deteching circuit a period of time, an exportable voltage and amplitude are all stabilized in the voice signal of setting in amplitude range, have improved the accuracy of identification to voice signal.
The course of work below in conjunction with describe the utility model automatic gain adjusting circuit with reference to figure 1:
Automatic gain adjusting circuit is to input speech signal Vin process automatic gain processing in certain limit, makes its output signal Vout amplitude equal to set amplitude Vm.But in the time that input speech signal Vin amplitude is very little, after variable gain amplifier, the amplitude of output voice signal VOUT is also very little, make voltage Vout also very little, now the second field effect transistor M2 does not open, and signal deteching circuit is not worked, as Vout < V
cutoff+ V
c(V
cutoffbe the cut-in voltage of the second field effect transistor M2), signal deteching circuit is not worked, and amplitude that also can not regulation output voice signal VOUT is to setting amplitude Vm; In the time of automatic gain adjusting circuit steady operation of the present utility model, be also input speech signal after automatic gain adjusting circuit, the amplitude of output voice signal VOUT is Vm, i.e. Vout=V
m=V
th2+ V
c(V
th2> V
cutoff).In the time of output voice signal changes in amplitude, detect feedback regulation by the signal deteching circuit of a period of time, make to export voice signal VOUT voltage and meet Vout=V
th2+ V
c, finally reach steady-working state.
When automatic gain adjusting circuit work, when external sound signal Vin is after variable gain amplifier, if when the amplitude of output voice signal VOUT is greater than setting amplitude Vm, i.e. Vout>=V
m=V
th2+ V
c, it is large that the electric current I ds2 of described the second field effect transistor M2 that makes to flow through becomes, and meanwhile, the electric current of described the 3rd field effect transistor M3 that flows through is also Ids2, described the 4th field effect transistor M4 is the electric current of the 3rd field effect transistor M3 described in mirror image by a certain percentage, the electric current I DS3 of described the 4th field effect transistor M4 of making to flow through also becomes large thereupon, now electric current I ds4 charges to capacitor C 1, the 6th field effect transistor M6 grid voltage is raise, because the 5th field effect transistor M5 is PMOS pipe, and grid connects ground voltage all the time, the 5th field effect transistor M5 is always in conducting state, so raising, the 6th field effect transistor M6 grid voltage makes output voltage V g lower voltage, become large by the known Rds1 of (1) (2) formula, Vout reduces, thereby realize negative feedback process, thereby make Vout finally be tending towards Vth2+Vc, so, after adjustment after a while, can make the amplitude of the voice signal VOUT of the output output of described amplifier OP1 fall after rise to setting amplitude Vm, make stable output signal.
In like manner, when external sound signal Vin is after variable gain amplifier, if when the amplitude of output voice signal VOUT is less than setting amplitude Vm, i.e. V
cutoff+ V
c≤ Vout≤V
m=V
th2+ V
c, the electric current I ds2 of described the second field effect transistor M2 that makes to flow through diminishes, and meanwhile, the electric current of described the 3rd field effect transistor M3 that flows through is also Ids2, described the 4th field effect transistor M4 is the electric current of the 3rd field effect transistor M3 described in mirror image by a certain percentage, the electric current I ds4 of described the 4th field effect transistor M4 of making to flow through also diminishes thereupon, now capacitor C 1 is discharged by described the second resistance R 2, the 6th field effect transistor M6 grid voltage is reduced, because the 5th field effect transistor M5 is PMOS pipe, and grid connects ground voltage all the time, the 5th field effect transistor M5 is always in conducting state, so the 6th field effect transistor M6 grid voltage reduces, output voltage V g voltage is raise, by (1) (2) formula, known Rds1 diminishes, it is large that Vout becomes, thereby realize negative feedback process, thereby make Vout finally be tending towards Vth2+Vc, so, after adjustment after a while, can make the amplitude of the voice signal VOUT of the output output of described amplifier OP1 rise to the amplitude Vm of setting, make stable output signal.
In conjunction with most preferred embodiment, the utility model is described above, but the utility model is not limited to the embodiment of above announcement, and should contains the various amendments of carrying out according to essence of the present utility model, equivalent combinations.
Claims (7)
1. an automatic gain adjusting circuit, for regulating the output amplitude of voice signal, it is characterized in that, comprise variable-gain amplification circuit, comparative voltage generative circuit and signal deteching circuit, described variable-gain amplification circuit receives the voice signal of outside input and the voice signal of input is amplified and exports the voice signal after amplification, described comparative voltage generative circuit is connected with described signal deteching circuit, be loaded on described signal deteching circuit to generate a reference voltage, and described reference voltage value is set according to the setting amplitude of output voice signal, described signal deteching circuit is connected with described variable-gain amplification circuit, described signal deteching circuit detects the amplitude of the voice signal of described variable-gain amplification circuit output, and the deviation of the amplitude of the voice signal of more described output and the amplitude of setting, in the time that the amplitude of the voice signal of described variable-gain amplification circuit output departs from setting amplitude, the voltage of a variation of described signal deteching circuit feedback is to described variable-gain amplification circuit, and described variable-gain amplification circuit is adjusted the amplitude of its output voice signal according to the voltage of this variation, so that the amplitude of the voice signal of described variable-gain amplification circuit output is identical with setting amplitude.
2. automatic gain adjusting circuit as claimed in claim 1, it is characterized in that, described variable-gain amplification circuit comprises amplifier, feedback resistance, the first adjustable resistance electronic circuit and the second adjustable resistance electronic circuit, the two ends of described feedback resistance are connected with reverse input end and the output of described amplifier respectively, the positive input of described amplifier receives external sound signal, described the first adjustable resistance electronic circuit is connected with the reverse input end of described amplifier, described the second adjustable resistance electronic circuit is connected with the positive input of described amplifier, and outside common-mode voltage is inputted respectively described the first adjustable resistance electronic circuit and the second adjustable resistance electronic circuit, described the first adjustable resistance electronic circuit is all connected with the output of described signal deteching circuit with the second adjustable resistance electronic circuit.
3. automatic gain adjusting circuit as claimed in claim 2, it is characterized in that, described the first adjustable resistance electronic circuit comprises the first field effect transistor and the first resistance, one end of the source electrode of described the first field effect transistor and the first resistance is all connected with outside common-mode voltage output, the other end of the drain electrode of described the first field effect transistor and the first resistance is all connected with the reverse input end of described amplifier, and the grid of described the first field effect transistor is connected with the output of described signal deteching circuit.
4. automatic gain adjusting circuit as claimed in claim 3, is characterized in that, described the first adjustable resistance electronic circuit and the second adjustable resistance electronic circuit have identical architectural feature.
5. automatic gain adjusting circuit as claimed in claim 4, it is characterized in that, the resistance of the first resistance of described the second adjustable resistance electronic circuit equals the first resistance of described the first adjustable resistance electronic circuit resistance value after in parallel with feedback resistance, and the first field effect transistor of described the first adjustable resistance electronic circuit and the second adjustable resistance electronic circuit is all operated in triode region.
6. automatic gain adjusting circuit as claimed in claim 1, is characterized in that, described signal deteching circuit comprises the second field effect transistor, the 3rd field effect transistor, the 4th field effect transistor, the 5th field effect transistor, the 6th field effect transistor, the second resistance and electric capacity, the grid of described the second field effect transistor is connected with the output of described variable-gain amplification circuit, and its source electrode is connected with described comparative voltage generative circuit, the drain electrode of the drain electrode of described the second field effect transistor and described the 3rd field effect transistor, the grid of grid and the 4th field effect transistor connects jointly, described the 3rd field effect transistor, the source electrode of the 4th field effect transistor and the 5th field effect transistor is all connected with external power source, the drain electrode of described the 4th field effect transistor, one end of the second resistance, the grid of one end of electric capacity and described the 6th field effect transistor connects jointly, and the drain electrode of described the 5th field effect transistor and the drain electrode of described the 6th field effect transistor are connected and form the output of described signal deteching circuit, the source electrode of described the 6th field effect transistor, the grid of the 5th field effect transistor, the other end of described the second resistance and the equal ground connection of the other end of described electric capacity.
7. automatic gain adjusting circuit as claimed in claim 1, it is characterized in that, described comparative voltage generative circuit comprises the 3rd resistance, the 4th resistance and voltage follower, described the 3rd resistance one end is connected with external power source, the other end is connected with described the 4th one end of resistance and the positive input of described voltage follower, the other end ground connection of described the 4th resistance, the reverse input end of described voltage follower is connected with its output, and the output of described voltage follower is connected with described signal deteching circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420026097.9U CN203747761U (en) | 2014-01-16 | 2014-01-16 | Automatic gain adjustment circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420026097.9U CN203747761U (en) | 2014-01-16 | 2014-01-16 | Automatic gain adjustment circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN203747761U true CN203747761U (en) | 2014-07-30 |
Family
ID=51347513
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201420026097.9U Expired - Fee Related CN203747761U (en) | 2014-01-16 | 2014-01-16 | Automatic gain adjustment circuit |
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| Country | Link |
|---|---|
| CN (1) | CN203747761U (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103762953A (en) * | 2014-01-16 | 2014-04-30 | 四川和芯微电子股份有限公司 | Automatic gain adjustment circuit |
| CN107294505A (en) * | 2017-06-19 | 2017-10-24 | 电信科学技术第研究所 | AGC system and its method of work |
-
2014
- 2014-01-16 CN CN201420026097.9U patent/CN203747761U/en not_active Expired - Fee Related
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103762953A (en) * | 2014-01-16 | 2014-04-30 | 四川和芯微电子股份有限公司 | Automatic gain adjustment circuit |
| CN103762953B (en) * | 2014-01-16 | 2016-05-04 | 四川和芯微电子股份有限公司 | Automatic gain adjusting circuit |
| CN107294505A (en) * | 2017-06-19 | 2017-10-24 | 电信科学技术第研究所 | AGC system and its method of work |
| CN107294505B (en) * | 2017-06-19 | 2020-10-16 | 电信科学技术第一研究所有限公司 | Automatic gain control system and working method thereof |
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