CN101154930B - Automatic gain control circuit - Google Patents
Automatic gain control circuit Download PDFInfo
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- CN101154930B CN101154930B CN2006101593118A CN200610159311A CN101154930B CN 101154930 B CN101154930 B CN 101154930B CN 2006101593118 A CN2006101593118 A CN 2006101593118A CN 200610159311 A CN200610159311 A CN 200610159311A CN 101154930 B CN101154930 B CN 101154930B
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Abstract
An automatic gain control circuit comprises a variable gain amplifier, a peak detecting circuit and an adjustable charging-and-discharging circuit. The variable gain amplifier receives the input signal and adjusts the input signal according to the gain factor control signal in order to generate the corresponding output signal. The peak detecting circuit is coupled to the variable gain amplifier and is used to generate the comparing signal according to the reference signal and the output signal. The adjustable charging-and-discharging circuit is coupled to the peak detecting circuit and the variable gain amplifier, and is used to output the charging current or discharging current according to the comparing signal to generate the gain factor control signal, wherein the ratio between the charging current and the discharging current is adjustable.
Description
Technical field
The invention provides a kind of automatic gain control circuit, refer to a kind of automatic gain control circuit that utilizes variable current source to adjust gain especially.
Background technology
In modern information-intensive society, various files, data, data and audio and video information can both be handled or transmitted in the mode of electronic signal, and the signal processing circuit that therefore can handle electronic signal also just becomes hardware foundation very important in the modernized information system.In information system, in order to handle electronic signal effectively, the magnitude of size of suitably keeping signal is one of key element, and therefore various gain amplifying circuits also just arise at the historic moment.Gain amplifying circuit can be considered amplifier, and its function is input signal gain back output, and adjusts its gain size by control signal.Wherein, variable-gain amplification circuit can carry out suitable adjustment to the magnitude of size of electronic signal; general regular meeting with variable-gain amplification circuit be designed to automatic gain control circuit (Automatic-Gain Control, AGC), automatically to regulate the magnitude of size of electronic signal.
Because the gain of variable-gain amplification circuit can be controlled by the value of control signal, the situation that its gain changes with control signal is the variable gain characteristic of variable-gain amplification circuit.In general, when design/manufacturing variable-gain amplification circuit, can wish that its variable gain characteristic has the gain ranging of broad, preferable controlled characteristic (similarly being to have high linear degree), and can suitably resist because of characteristic drifts that external factor caused such as processing procedure or operational temperature variations.Variable-gain amplification circuit with big gain ranging can change its gain significantly, thus can adapt to the electronic signal of more kinds of different amplitudes, thereby have higher using value.The controlled characteristic of variable-gain amplification circuit is good more, represents the situation of its change in gain to be controlled more explicitly, also just can realize out preferable variable gain characteristic.When variable-gain amplification circuit can suitably be resisted processing procedure or characteristic drift that temperature variations caused, its variable gain characteristic will be not can be because of these undesirable factors change significantly, and then influence the general performance of system.
Please refer to Fig. 1, Fig. 1 is the schematic diagram of variable-gain amplification circuit 10 in the prior art.Variable-gain amplification circuit 10 comprises variable gain amplifier (Variable-Gain Amplifier, VGA) 12, peak detection circuit (Peak-Detecting Circuit) 14, fixed charge-discharge circuit 16 and digital/analog converter (Digital-to-Analog Converter, DAC) 18.Variable gain amplifier 12 is in its input receiving inputted signal V
IN, and according to gain control signal V
CTLCome amplification input signal V
IN, to produce corresponding output signal V in its output
OUTIn variable-gain amplification circuit 10, gain control signal V
CTLBe according to output signal V by peak detection circuit 14 and fixed charge-discharge circuit 16
OUTProduce, therefore can carry out automatic gain control by feedback system.
Formerly in the variable-gain amplification circuit 10 of technology, by the different minimum detectable signal V of digital/analog converter 18 outputs
T' produce different gain control signal V
CTL, therefore can adjust the gain of variable gain amplifier 12.Peak detection circuit 14 comprises positive differential comparator 21, anti-phase differential comparator 22 and or door (OR Gate) 23.The positive input terminal of positive differential comparator 21 is coupled to variable gain amplifier 12 to receive output signal V
OUT, and the negative input end of positive differential comparator 21 is coupled to digital/analog converter 18 to receive minimum detectable signal V
T', positive differential comparator 21 can utilize differential mode to come comparison output signal V
OUTWith minimum detectable signal V
T' value, and produce corresponding positive phase comparison signal V in its output
+The positive input terminal of anti-phase differential comparator 22 is coupled to digital/analog converter 18 to receive minimum detectable signal V
T', and the negative input end of anti-phase differential comparator 22 is coupled to variable gain amplifier 12 to receive output signal V
OUT, anti-phase differential comparator 22 can utilize differential mode to come comparison output signal V
OUTAnti-phase and minimum detectable signal V
T' value, and produce corresponding anti-phase comparison signal V in its output
-Or door 23 output that is coupled to positive differential comparator 21 and anti-phase differential comparator 22, can be according to positive phase comparison signal V
+And anti-phase comparison signal V
-Produce corresponding comparison signal V
GATE
Fixed charge-discharge circuit 16 comprises capacitor C, fixed charging current source I
P, fixed discharging current source I
N, charge switch SW
P, and discharge switch SW
NCharge switch SW
PCan be P-type mos transistor (P-type Metal Oxide Semiconductor Transistor, PMOS) switch SW
P, and discharge switch SW
NCan be N type metal oxide semiconductor transistor (N-type Metal OxideSemiconductor Transistor, NMOS) switch SW
NCharge switch SW
PWith discharge switch SW
NGrid be coupled to or the door 23, as comparison signal V
GATEDuring for high potential, charge switch SW
PBe and close (opening circuit), discharge switch SW
NBe unlatching (short circuit), this moment, fixed charge-discharge circuit 16 can be by fixed discharging current source I
NWith discharge switch SW
NCome capacitor C is discharged; As comparison signal V
GATEDuring for electronegative potential, charge switch SW
PBe unlatching, discharge switch SW
NBe and close, this moment, fixed charge-discharge circuit 16 can be by fixed charging current source I
PWith charge switch SW
PCome capacitor C is charged.Formerly in the variable-gain amplification circuit 10 of technology, fixed charging current source I
PWith fixed discharging current source I
NProvide the charging and the discharging current of fixed value.
Please refer to Fig. 2, the signal graph when Fig. 2 is variable-gain amplification circuit 10 running of prior art.In Fig. 2, output signal V
OUTWaveform represent that by the string ripple its amplitude is V
M, and centered level is V
REFTransverse axis is represented the time, explains with one-period (0～2 π) in Fig. 2.As output signal V
OUTAbsolute value less than minimum detectable signal V
TAbsolute value the time, this moment, fixed charge-discharge circuit 16 can be carried out charging operations, for example 0 to θ, (π-θ) is to (π+θ) and (2 π-θ) to 2 π interval (being represented by the hatched example areas in Fig. 2 string ripple); As output signal V
OUTAbsolute value greater than minimum detectable signal V
T' absolute value the time, this moment, fixed charge-discharge circuit 16 can be carried out discharge operations, for example at θ to (π-θ) and (π+θ) is to (in 2 π-θ) interval (being represented by the white space in Fig. 2 string ripple).The value of θ is relevant to minimum detectable signal V
T' level, minimum detectable signal V
T' absolute value big more, the charging interval T of fixed charge-discharge circuit 16
P(T
P=4 θ) long more; Minimum detectable signal V
TAbsolute value more little, T discharge time of fixed charge-discharge circuit 16
N(T
N=2 π-4 θ) long more.
When variable-gain amplification circuit 10 is carried out charging and discharge operation, charging charge Q
PWith discharge charge Q
NCan represent by following formula respectively:
Q
P＝I
PT
P＝I
P(4θ)；
Q
N＝I
NT
N＝I
N(2π-4θ)
When variable-gain amplification circuit 10 is stablized, charging charge Q
PWith discharge charge Q
NCan reach balance, that is:
Q
P＝Q
N；
I
N/I
P＝2θ/(π-2θ)
Represent I with N
N/ I
PValue, the value of θ then can be represented by following formula:
In addition, output signal V
OUTAmplitude V
MWith minimum detectable signal V
T' following relationship: V arranged
MSin θ=V
T'
Therefore,
In order to make the preferable controlled characteristic of variable-gain amplification circuit 10 tools, generally can wish minimum detectable signal V
T' value be bordering on output signal V
OUTTarget amplitude V
M, so by adjusting minimum detectable signal V
T' value can change output signal V
OUTValue.Therefore, minimum detectable signal V
T' absolute value need level off to target amplitude V
MAbsolute value, meaning is that the value of θ need level off to pi/2, the value of N then is the bigger the better.Formerly in the variable-gain amplification circuit 10 of technology, generally the N value can be made as fixed value (for example N=10), by adjusting minimum detectable signal V
T' value change output signal V
OUTTarget amplitude V
M, and variable-gain amplification circuit 10 also can have preferable controlled characteristic.
Formerly in the variable-gain amplification circuit 10 of technology, because minimum detectable signal V
T' value be bordering on output signal V
OUTTarget amplitude V
M, need make the positive differential comparator 21 and the anti-phase differential comparator 22 of the high arithmetic speed of apparatus, could judge output signal V exactly
OUTMinimum detectable signal V
T' between size so that variable-gain amplification circuit 10 can correctly switch between charge and discharge.In addition, the variable-gain amplification circuit 10 of prior art also need use digital/analog converter 18 that different minimum detectable signal V is provided
T', digital/analog converter 18 can occupy circuit space, and can consumed energy.
Summary of the invention
The purpose of this invention is to provide automatic gain control circuit, to solve positive differential comparator and anti-phase differential comparator and the big and high problem of energy consumption of the needs use circuit space that digital/analog converter was brought that needs to have high arithmetic speed in the prior art.
The invention provides a kind of automatic gain control circuit, it comprises variable gain amplifier, is used for receiving inputted signal, and adjusts this input signal to produce corresponding output signal according to the gain factor control signal; Peak detection circuit is coupled to this variable gain amplifier, is used for producing comparison signal according to reference signal and this output signal; And adjustable charge-discharge circuit, the input of this adjustable charge-discharge circuit is coupled to this peak detection circuit, the output of this adjustable charge-discharge circuit is coupled to this variable gain amplifier, be used for according to this comparison signal output charging current or discharging current to produce this gain factor control signal, wherein the ratio of this charging current and this discharging current is for adjusting.
By adopting variable-gain amplification circuit of the present invention, only need make apparatus low/differential comparator of middle arithmetic speed, therefore can save the cost of differential comparator.In addition, the present invention also need not use digital/analog converter that different minimum detectable signals is provided, and provides the minimum detectable signal of fixed value, therefore can save circuit space and reduce energy consumption.
Description of drawings
Fig. 1 is the schematic diagram of variable-gain amplification circuit in the prior art.
Fig. 2 is the signal graph in variable-gain amplification circuit when running of Fig. 1.
Fig. 3 is the schematic diagram of variable-gain amplification circuit in the first embodiment of the invention.
Fig. 4 is the signal graph in variable-gain amplification circuit when running of Fig. 3.
Fig. 5 is the schematic diagram of variable-gain amplification circuit in the second embodiment of the invention.
Fig. 6 is the schematic diagram of variable-gain amplification circuit in the third embodiment of the invention.
[main element label declaration]
12,32 variable gain amplifiers, 14,34 peak detection circuits
16 fixed charge-discharge circuit 18,19 digital/analog converters
21,41 positive differential comparators, 22,42 anti-phase differential comparators
23 or the door 43 arithmetic and logical units
C electric capacity 38 filters
I
PFixed charging current source I
P' the type variable charging current source
I
NFixed discharging current source I
N' type variable discharging current source
SW
PCharge switch SW
NDischarge switch
36,56,66 adjustable charge-discharge circuits
10,30,50,60 variable-gain amplification circuits
Embodiment
Please refer to Fig. 3, Fig. 3 is the schematic diagram of variable-gain amplification circuit 30 in the first embodiment of the invention.Variable-gain amplification circuit 30 comprises variable gain amplifier 32, peak detection circuit 34, adjustable charge-discharge circuit 36 and filter 38.Variable gain amplifier 32 is in its input receiving inputted signal V
IN, and according to gain control signal V
CTLAdjust input signal V
IN, to produce corresponding output signal V in its output
OUTFilter 38 is coupled between variable-gain amplification circuit 32 and the peak detection circuit 34, its role is to remove the offset voltage of variable gain amplifier 32 and then redefines output signal V
OUTThe operating voltage point.In variable-gain amplification circuit 30, gain control signal V
CTLBe according to output signal V by peak detection circuit 34 and adjustable charge-discharge circuit 36
OUTProduce, therefore can carry out automatic gain control by feedback system.
In variable-gain amplification circuit 30 of the present invention, produce different gain control signal V by adjustable charge-discharge circuit 36
CTL, therefore can adjust the gain of variable gain amplifier 32.Peak detection circuit 34 comprises positive differential comparator 41, anti-phase differential comparator 42 and arithmetic and logical unit 43.The positive input terminal of positive differential comparator 41 is coupled to variable gain amplifier 32 to receive output signal V
OUT, and the negative input end of positive differential comparator 21 can receive the first reference signal V of fixed value
T1, positive differential comparator 41 can utilize differential mode to come comparison output signal V
OUTWith the first reference signal V
T1Value, and produce corresponding positive phase comparison signal V in its output
+The positive input terminal of anti-phase differential comparator 42 can receive the second reference signal V of fixed value
T2, and the negative input end of anti-phase differential comparator 42 is coupled to variable gain amplifier 32 to receive output signal V
OUT, anti-phase differential comparator 42 can utilize differential mode to come comparison output signal V
OUTWith the second reference signal V
T2, and produce corresponding anti-phase comparison signal V in its output
-Arithmetic and logical unit 43 can be or door, is coupled to the output of positive differential comparator 41 and anti-phase differential comparator 42, and can be according to positive phase comparison signal V
+And anti-phase comparison signal V
1Produce corresponding comparison signal V
GATE
Adjustable charge-discharge circuit 36 comprises capacitor C, fixed charging current source I
P, type variable discharging current source I
N', charge switch SW
P, and discharge switch SW
NCharge switch SW
PCan be the PMOS switch, and discharge switch SW
NCan be nmos switch.Charge switch SW
PWith discharge switch SW
NGrid be coupled to arithmetic and logical unit 43, as comparison signal V
GATEDuring for high potential, charge switch SW
PBe and close (opening circuit), nmos switch SW
NBe unlatching (short circuit), this moment, 36 meetings of adjustable charge-discharge circuit were by type variable discharging current source I
N' and discharge switch SW
NCome capacitor C is discharged; As comparison signal V
GATEDuring for electronegative potential, charge switch SW
PBe unlatching, discharge switch SW
NBe and close, this moment, 36 meetings of adjustable charge-discharge circuit were by fixed charging current source I
PWith charge switch SW
PCome capacitor C is charged.In variable-gain amplification circuit 30 of the present invention, fixed charging current source I
PWith type variable discharging current source I
N' provide the charging and discharging current between ratio for adjusting.
Please refer to Fig. 4, the signal graph when Fig. 4 is variable-gain amplification circuit of the present invention 30 runnings.In Fig. 4, output signal V
OUTWaveform represent that by the string ripple its amplitude is V
M, and centered level is V
REFTransverse axis is represented the time, explains with one-period (0～2 π) in Fig. 4.In the embodiment of Fig. 4, suppose the first reference signal V
T1With the second reference signal V
T2Value all be made as fixing minimum detectable signal V
T, as output signal V
OUTAbsolute value less than minimum detectable signal V
TAbsolute value the time, this moment, the adjustable charge-discharge circuit 36 can be carried out charging operations, for example 0 to θ, (π-θ) is to (π+θ) and (2 π-θ) are to the interval (being represented by the hatched example areas in Fig. 4 string ripple) of 2 π; As output signal V
OUTAbsolute value greater than minimum detectable signal V
TAbsolute value the time, this moment, charge-discharge circuit 36 can be carried out discharge operations, for example at θ to (π-θ) and (π+θ) is to (the interval (being represented by the white space in Fig. 4 string ripple) of 2 π-θ).The value of θ is relevant to minimum detectable signal V
TLevel, minimum detectable signal V
TAbsolute value big more, the charging interval T of adjustable charge-discharge circuit 36
P(T
P=4 θ) long more; Minimum detectable signal V
TAbsolute value more little, T discharge time of adjustable charge-discharge circuit 36
N(T
N=2 π-4 θ) long more.
When variable-gain amplification circuit 30 is carried out charging and discharge operation, charging charge Q
PWith discharge charge Q
NCan represent by following formula respectively:
Q
P＝I
PT
P＝I
P(4θ)；
Q
N＝I
NT
N＝I
N(2π-4θ)
When variable-gain amplification circuit 30 is stablized, charging charge Q
PWith discharge charge Q
NCan reach balance, that is:
Q
P＝Q
N＝；
I
N/I
P＝2θ/(π-2θ)
Represent I with N '
N'/I
PValue, the value of θ then can be represented by following formula:
In addition, output signal V
OUTAmplitude V
MWith minimum detectable signal V
TFollowing relationship is arranged:
V
Msinθ＝V
T
Therefore,
In the variable-gain amplification circuit 30 of first embodiment of the invention, minimum detectable signal V
TValue for fixing, and do not need to approach output signal V
OUTTarget amplitude V
M, and can change the gain of variable gain amplifier 32 by the value of adjusting N '.Therefore, the present invention only need make apparatus low/the positive differential comparator 41 and the anti-phase differential comparator 42 of middle arithmetic speed, can judge output signal V exactly
OUTWith minimum detectable signal V
TBetween size so that variable-gain amplification circuit 30 can correctly switch, therefore can save the cost of differential comparator between charge and discharge.In addition, variable-gain amplification circuit 30 of the present invention need not use digital/analog converter that different minimum detectable signals is provided, and provides first and second reference signal V of fixed value
T1And V
T2(first and second reference signal V
T1And V
T2Can be made as fixing minimum detectable signal V simultaneously
T), therefore can save circuit space and reduce energy consumption.
Please refer to Fig. 5, Fig. 5 is the schematic diagram of variable-gain amplification circuit 50 in the second embodiment of the invention.Variable-gain amplification circuit 50 comprises variable gain amplifier 32, peak detection circuit 34, adjustable charge-discharge circuit 56 and filter 38.In second embodiment of the invention, adjustable charge-discharge circuit 56 comprises capacitor C, type variable charging current source I
P', fixed discharging current source I
N, charge switch SW
P, and discharge switch SW
NRepresent I with N ' equally
N/ I
P' value, and suppose the first reference signal V
T1With the second reference signal V
T2Value all be made as fixing minimum detectable signal V
T, output signal V
OUTAmplitude V
MWith minimum detectable signal V
TFollowing relationship is also arranged:
Therefore the variable-gain amplification circuit 50 of second embodiment of the invention also can change the gain of variable gain amplifier 32 by the value of adjusting N '.Only need make apparatus low/the positive differential comparator 41 and the anti-phase differential comparator 42 of middle arithmetic speed, variable-gain amplification circuit 50 can be judged output signal V exactly
OUTWith minimum detectable signal V
TBetween size, correctly between charge and discharge, switching, therefore can save the cost of differential comparator.In addition, the variable-gain amplification circuit 50 of second embodiment of the invention also need not use digital/analog converter that different minimum detectable signals is provided, and provides first and second reference signal V of fixed value
T1And V
T2(first and second reference signal V
T1And V
T2Can be made as fixing minimum detectable signal V simultaneously
T), therefore can save circuit space and reduce energy consumption.
Please refer to Fig. 6, Fig. 6 is the schematic diagram of variable-gain amplification circuit 60 in the third embodiment of the invention.Variable-gain amplification circuit 60 comprises variable gain amplifier 32, peak detection circuit 34, adjustable charge-discharge circuit 66 and filter 38.In third embodiment of the invention, adjustable charge-discharge circuit 66 comprises capacitor C, type variable charging current source I
P', type variable discharging current source I
N', charge switch SW
P, and discharge switch SW
NRepresent I with N ' equally
N'/I
P' value, and suppose the first reference signal V
T1With the second reference signal V
T2Value all be made as fixing minimum detectable signal V
T, output signal V
OUTAmplitude V
MWith minimum detectable signal V
TFollowing relationship is also arranged:
Therefore the variable-gain amplification circuit 60 of third embodiment of the invention also can change the gain of variable gain amplifier 32 by the value of adjusting N '.Only need make apparatus low/the positive differential comparator 41 and the anti-phase differential comparator 42 of middle arithmetic speed, variable-gain amplification circuit 60 can be judged output signal V exactly
OUTWith minimum detectable signal V
TBetween size, correctly between charge and discharge, switching, therefore can save the cost of differential comparator.In addition, the variable-gain amplification circuit 60 of third embodiment of the invention also need not use digital/analog converter that different minimum detectable signals is provided, and provides first and second reference signal V of fixed value
T1And V
T2(first and second reference signal V
T1And V
T2Can be made as fixing minimum detectable signal V simultaneously
T), therefore can save circuit space and reduce energy consumption.
Variable-gain amplification circuit of the present invention uses variable current source to adjust the size of charge or discharge electric current, and then adjusts the yield value of variable gain amplifier.Since only need make apparatus low/differential comparator of middle arithmetic speed, therefore can save the cost of differential comparator.In addition, the present invention also need not use digital/analog converter that different minimum detectable signals is provided, and provides the minimum detectable signal of fixed value, therefore can save circuit space and reduce energy consumption.
The above only is preferred embodiment of the present invention, and all equalizations of being done according to claim scope of the present invention change and modify, and all should belong to covering scope of the present invention.
Claims (14)
1. automatic gain control circuit, it comprises:
Variable gain amplifier is used for receiving inputted signal, and adjusts this input signal to produce corresponding output signal according to the gain factor control signal;
Peak detection circuit is coupled to this variable gain amplifier, is used for producing comparison signal according to reference signal and this output signal;
It is characterized in that further comprising:
The adjustable charge-discharge circuit, the input of this adjustable charge-discharge circuit is coupled to this peak detection circuit, the output of this adjustable charge-discharge circuit is coupled to this variable gain amplifier, be used for according to this comparison signal output charging current or discharging current to produce this gain factor control signal, wherein the ratio of this charging current and this discharging current is for adjusting.
2. automatic gain control circuit according to claim 1, wherein this adjustable charge-discharge circuit comprises:
The type variable charging current source is used to provide variable charge current;
Fixed discharging current source is used to provide fixedly discharging current;
First switch is used for controlling current flowing path between the output of this type variable charging current source and this adjustable charge-discharge circuit according to this comparison signal; And
Second switch is used for controlling current flowing path between the output of this fixed discharging current source and this adjustable charge-discharge circuit according to this comparison signal.
3. automatic gain control circuit according to claim 2, it also comprises:
Electric capacity is coupled to the output of this adjustable charge-discharge circuit, be used for according to this variable charge current and fixedly discharging current produce this gain factor control signal.
4. automatic gain control circuit according to claim 2, wherein this first switch is the P-type mos transistor switch, and this second switch is a N type metal oxide semiconductor transistor switch.
5. automatic gain control circuit according to claim 1, wherein this adjustable charge-discharge circuit comprises:
Fixed charging current source is used to provide fixedly charging current;
Type variable discharging current source is used to provide variable discharging current;
First switch is used for controlling current flowing path between the output of this fixed charging current source and this adjustable charge-discharge circuit according to this comparison signal; And
Second switch is used for controlling current flowing path between the output of this type variable discharging current source and this adjustable charge-discharge circuit according to this comparison signal.
6. automatic gain control circuit according to claim 5, it also comprises:
Electric capacity is coupled to the output of this adjustable charge-discharge circuit, is used for reaching this variable discharging current according to fixing charging current and produces this gain factor control signal.
7. automatic gain control circuit according to claim 6, wherein this first switch is the P-type mos transistor switch, and this second switch is a N type metal oxide semiconductor transistor switch.
8. automatic gain control circuit according to claim 1, wherein this adjustable charge-discharge circuit comprises:
The type variable charging current source is used to provide variable charge current;
Type variable discharging current source is used to provide variable discharging current;
First switch is used for controlling current flowing path between the output of this type variable charging current source and this adjustable charge-discharge circuit according to this comparison signal; And
Second switch is used for controlling current flowing path between the output of this type variable discharging current source and this adjustable charge-discharge circuit according to this comparison signal.
9. automatic gain control circuit according to claim 8, it also comprises:
Electric capacity is coupled to the output of this adjustable charge-discharge circuit, is used for producing this gain factor control signal according to this variable charge current and this variable discharging current.
10. automatic gain control circuit according to claim 8, wherein this first switch is the P-type mos transistor switch, and this second switch is a N type metal oxide semiconductor transistor switch.
11. automatic gain control circuit according to claim 1, wherein this peak detection circuit comprises:
The positive differential comparator is coupled to this variable gain amplifier, is used for comparing first reference signal and this output signal in differential mode, and produces corresponding positive phase comparison signal;
Anti-phase differential comparator is coupled to this variable gain amplifier, is used for comparing second reference signal and this output signal in differential mode, and produces corresponding anti-phase comparison signal; And
Arithmetic and logical unit is coupled to this positive differential comparator, this anti-phase differential comparator and this adjustable charge-discharge circuit, is used for producing this comparison signal according to this positive phase comparison signal and this anti-phase comparison signal.
12. automatic gain control circuit according to claim 11, wherein this arithmetic and logical unit is or door.
13. automatic gain control circuit according to claim 11, wherein this first reference signal is identical with this second reference signal.
14. automatic gain control circuit according to claim 1, it also comprises filter, is coupled between this variable gain amplifier and this peak detection circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2006101593118A CN101154930B (en) | 2006-09-27 | 2006-09-27 | Automatic gain control circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2006101593118A CN101154930B (en) | 2006-09-27 | 2006-09-27 | Automatic gain control circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN101154930A CN101154930A (en) | 2008-04-02 |
| CN101154930B true CN101154930B (en) | 2010-06-23 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2006101593118A Expired - Fee Related CN101154930B (en) | 2006-09-27 | 2006-09-27 | Automatic gain control circuit |
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Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8004354B1 (en) * | 2010-02-12 | 2011-08-23 | Taiwan Semiconductor Manufacturing Company, Ltd. | Automatic level control |
| US8639199B1 (en) * | 2012-08-24 | 2014-01-28 | Mcafee, Inc. | System and method for high performance coherent peak compression estimation |
| CN103414440A (en) * | 2013-08-14 | 2013-11-27 | 董志伟 | Signal amplification circuit with time-varying gain |
| CN104734653B (en) * | 2013-12-20 | 2017-06-16 | 瑞昱半导体股份有限公司 | The control method of reception device and its amplification coefficient |
| CN111884665B (en) * | 2020-09-28 | 2021-01-01 | 中国人民解放军国防科技大学 | Digital receiver automatic gain control method based on maximum entropy |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5377231A (en) * | 1993-11-30 | 1994-12-27 | At&T Corp. | Automatic gain control circuit for a digital baseband line equalizer |
| US6608521B1 (en) * | 2002-05-14 | 2003-08-19 | Texas Instruments Incorporated | Pulse width modulation regulator control circuit having precise frequency and amplitude control |
| CN1671050A (en) * | 2004-09-30 | 2005-09-21 | 东南大学 | Fixed amplitude circuit for voltage controlled oscillator |
-
2006
- 2006-09-27 CN CN2006101593118A patent/CN101154930B/en not_active Expired - Fee Related
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5377231A (en) * | 1993-11-30 | 1994-12-27 | At&T Corp. | Automatic gain control circuit for a digital baseband line equalizer |
| US6608521B1 (en) * | 2002-05-14 | 2003-08-19 | Texas Instruments Incorporated | Pulse width modulation regulator control circuit having precise frequency and amplitude control |
| CN1671050A (en) * | 2004-09-30 | 2005-09-21 | 东南大学 | Fixed amplitude circuit for voltage controlled oscillator |
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|---|---|
| CN101154930A (en) | 2008-04-02 |
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