CN103580634A - Automatic gain controller in audio signal analysis - Google Patents
Automatic gain controller in audio signal analysis Download PDFInfo
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- CN103580634A CN103580634A CN201310542745.6A CN201310542745A CN103580634A CN 103580634 A CN103580634 A CN 103580634A CN 201310542745 A CN201310542745 A CN 201310542745A CN 103580634 A CN103580634 A CN 103580634A
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- amplifier chip
- resistance
- audio signal
- operational amplifier
- variable gain
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Abstract
The invention belongs to the technical field of signal processing and discloses an automatic gain controller in audio signal analysis. The automatic gain controller in audio signal analysis comprises a variable gain amplifier chip and an operational amplifier chip. The output end of the variable gain amplifier chip is connected to the input end of the operational amplifier chip and the output end of the operational amplifier chip is connected with the gain control end of the variable gain amplifier chip. The automatic gain controller in audio signal analysis is simple in circuit, stable in work, capable of achieving closed-loop control, short in hardware implementation delay, free of extra control signals, continuously adjustable in control range and capable of effectively improving the measurement accuracy.
Description
Technical field
The present invention relates to a kind of gain converting circuit, relate in particular to the automatic gain controller in a kind of audio signal analysis, belong to signal processing technology field.
Background technology
Audio signal is a kind of common processing signals in prior art.When unknown audio signal (as microphone input signal) is analyzed, due to audio frequency signal amplitude wide ranges and come and go and AD conversion range is limited, and the power of the audio signal receiving is unpredictable, if strong signal enters receiver, can cause amplifier compression artefacts and A/D converter cisco unity malfunction, now need strong signal to decay; And to the weak signal receiving, for rear class A/D converter is operated within the scope of optimum sensitivity, after need to amplifying it, enter again A/D converter.The visible audio signal to reception need to be amplified or decay conventionally, thereby makes A/D converter in ideal operation state, so just can obtain measurement result accurately.
For the signal of receiving that achieves a butt joint amplifies or decays, traditional method is: signal is divided into multistage amplification, multistage decay, straight-through three paths, by switch, controls, and selects signal path.Also need signal predetection, according to detection result, split to close and control.This method realizes circuit complexity, controls loaded down with trivial detailsly, generally needs software to participate in, and needs certain reaction time, easily causes device failure.And owing to being that switch is controlled, it is large that range switches span, can not make full use of AD range.
Can therefore, design a kind of novel gain controller to overcome above-mentioned one or more defects, becoming those skilled in the art has technical barrier to be solved.
Summary of the invention
Because the above-mentioned defect of prior art, the present invention aims to provide the automatic gain controller in a kind of audio signal analysis, by the gain-controlled voltage of closed-loop adjustment controllable gain amplifier, the gain transformations of realization-40dB～+ 40dB, overcome the shortcoming of prior art, its circuit is simple, working stability, closed-loop control, it is little that hardware is realized delay, and without outer increase control signal, and control range is adjustable continuously, the overwhelming majority of input signal can both be adjusted in the best input range of AD, effectively improves certainty of measurement.
The present invention realizes like this, automatic gain controller in this audio signal analysis comprises: variable gain amplifier chip U1, operational amplifier chip U2, the output of variable gain amplifier chip U1 is connected to the input of operational amplifier chip U2, and the output of operational amplifier chip U2 is connected to the gain control end V of variable gain amplifier chip U1
c.
In some technical schemes, also comprise diode D1, resistance R 1-R4, capacitor C
cand C
hwherein, the signal input positive ending grounding of variable gain amplifier chip U1, signal input negative terminal connects input audio signal, the output of variable gain amplifier chip U1 is connected to the signal input anode of operational amplifier chip U2, resistance R 4 one termination DC reference voltage end VR, the signal input negative terminal of another termination operational amplifier chip U2, capacitor C
cbe connected between the signal input negative terminal and output thereof of operational amplifier chip U2 the output terminating diode D1 anode of operational amplifier chip U2, the gain control end V of variable gain amplifier chip U1
crespectively with resistance R 1-R3, capacitor C
hone end is connected, and resistance R 1 other end is connected with biased electrical pressure side V-, resistance R 2 and capacitor C
hother end ground connection, resistance R 3 other ends are connected with diode D1 negative terminal.
In some technical schemes, audio signal is the AC signal of amplitude 2mV-2V, frequency 300Hz-20kHz.
In some technical schemes, resistance R 1 is 50 kilo-ohms with R2 resistance, and R3 resistance is 1 kilo-ohm, capacitor C
ccapacitance is 0.1 microfarad, C
hcapacitance is 47 pico farads.
In some technical schemes, variable gain amplifier chip U1 is VCA810, and operational amplifier chip U2 is OPA820, and diode D1 is HP5082.
Compared with prior art, beneficial effect of the present invention is as follows:
1) simplify circuit, improved reliability;
2) in the situation that AD converter is constant, greatly expanded the measuring range of audio signal;
3) self adaptation is controlled in gain, and hardware circuit is realized without postponing;
4) gain control is adjustable continuously, effectively improves signal measurement precision.
Below with reference to accompanying drawing, the technique effect of design of the present invention, concrete structure and generation is described further, to understand fully object of the present invention, feature and effect.
Accompanying drawing explanation
Fig. 1 is the circuit theory diagrams of automatic gain controller one embodiment in audio signal analysis of the present invention.
Embodiment
Be illustrated in figure 1 the embodiment of the invention, automatic gain controller in this audio signal analysis comprises variable gain amplifier chip U1, operational amplifier chip U2, the output of variable gain amplifier chip U1 is connected to the input of operational amplifier chip U2, and the output of operational amplifier chip U2 is connected to the gain control end V of variable gain amplifier chip U1
c.
In a better embodiment, also comprise diode D1, resistance R 1-R4, capacitor C
cand C
hwherein, the signal input positive ending grounding of variable gain amplifier chip U1, signal input negative terminal connects input audio signal, the output of variable gain amplifier chip U1 is connected to the signal input anode of operational amplifier chip U2, resistance R 4 one termination DC reference voltage end VR, the signal input negative terminal of another termination operational amplifier chip U2, capacitor C
cbe connected between the signal input negative terminal and output thereof of operational amplifier chip U2 the output terminating diode D1 anode of operational amplifier chip U2, the gain control end V of variable gain amplifier chip U1
crespectively with resistance R 1-R3, capacitor C
hone end is connected, and resistance R 1 other end is connected with biased electrical pressure side V-, resistance R 2 and capacitor C
hother end ground connection, resistance R 3 other ends are connected with diode D1 negative terminal.
For variable gain amplifier chip U1, operational amplifier chip U2 can be worked, also power positive end VS+ (being for example+5V), power supply negative terminal VS-(being for example-5V) are connected to their corresponding power pin, this is content well known in the art, does not repeat them here.
The voltage of DC reference voltage end VR, biased electrical pressure side V-can be preset and adjust according to specific requirement.
In this automatic gain controller circuit, operational amplifier chip U2 and diode D1 detect for carrying out the output amplitude of variable gain amplifier chip U1, capacitor C
hfor storage gain, control voltage, and by determining charging, discharge time, resistance R 4 and capacitor C with charging, the discharge loop of resistance R 1, R3 formation
cphase compensation for feedback loop, operational amplifier chip U2 compares the amplitude of output voltage with DC reference voltage VR, when the amplitude of output voltage surpasses VR, operational amplifier chip U2 output forward migration amount, diode D1 conducting is also passed through resistance R 3 to capacitor C
hcharging, makes V
cincrease, the gain of variable gain amplifier chip U1 reduces, capacitor C
hdetermined the charging interval in gain adjustment with the parameter of resistance R 3; Meanwhile, capacitor C
hby resistance R 1, discharge, make V
creduce, the gain of variable gain amplifier chip U1 raises, resistance R 1, R2 and capacitor C
hparameter determined the discharge time of gain in adjusting; Resistance R 2 forms voltage divider with R1, is used for limiting being supplied to capacitor C
hmaximum negative voltage, thereby prevent the input overload of this circuit.
In a better embodiment, this audio signal is preferably the AC signal of amplitude 2mV-2V, frequency 300Hz-20kHz.
In a better embodiment, resistance R 1 is 50 kilo-ohms with R2 resistance, and R3 resistance is 1 kilo-ohm, capacitor C
ccapacitance is 0.1 microfarad, C
hcapacitance is 47 pico farads.
In a better embodiment, variable gain amplifier chip U1 is VCA810, and operational amplifier chip U2 is OPA820, and diode D1 is HP5082.
The application of the automatic gain controller in brief description audio signal analysis of the present invention:
When using this automatic gain controller to carry out audio signal analysis, when the audio frequency signal amplitude of input diminishes, output voltage diminishes, and its amplitude is less than DC reference voltage VR, diode D1 cut-off, capacitor C
hby resistance R 1, discharge, make V
creduce, the gain of variable gain amplifier chip U1 raises, and output voltage increases; When the amplitude of output voltage surpasses VR, operational amplifier chip U2 output forward migration amount, diode D1 conducting is also passed through resistance R 3 to capacitor C
hcharging, makes V
cincrease, the gain of variable gain amplifier chip U1 reduces, and output voltage reduces.So by negative feedback, constantly automatically regulate gain, the overwhelming majority of input signal can both be adjusted in the best input range of AD to be exported, without converting the AD converter measuring range of extended audio signal greatly, and circuit is simple and reliable, without hardware delay, certainty of measurement significantly improves.
More than describe preferred embodiment of the present invention in detail.Should be appreciated that those of ordinary skill in the art just can design according to the present invention make many modifications and variations without creative work.Therefore, all technical staff in the art, all should be in the determined protection range by claims under this invention's idea on the basis of existing technology by the available technical scheme of logical analysis, reasoning, or a limited experiment.
Claims (5)
1. the automatic gain controller in an audio signal analysis, it is characterized in that, comprise variable gain amplifier chip U1 and operational amplifier chip U2, the output of described variable gain amplifier chip U1 is connected to the input of described operational amplifier chip U2, and the output of described operational amplifier chip U2 is connected to the gain control end V of described variable gain amplifier chip U1
c.
2. the automatic gain controller in a kind of audio signal analysis as claimed in claim 1, is characterized in that, also comprises diode D1, resistance R 1-R4, capacitor C
cand C
hwherein, the signal input positive ending grounding of described variable gain amplifier chip U1, signal input negative terminal connects input audio signal, the output of described variable gain amplifier chip U1 is connected to the signal input anode of described operational amplifier chip U2, resistance R 4 one termination DC reference voltage end VR, the signal of operational amplifier chip U2 input negative terminal described in another termination, described capacitor C
cbe connected between the signal input negative terminal and output thereof of described operational amplifier chip U2 the output terminating diode D1 anode of described operational amplifier chip U2, the gain control end V of described variable gain amplifier chip U1
crespectively with described resistance R 1-R3, capacitor C
hone end is connected, and resistance R 1 other end is connected with biased electrical pressure side V-, resistance R 2 and capacitor C
hother end ground connection, resistance R 3 other ends are connected with diode D1 negative terminal.
3. the automatic gain controller in a kind of audio signal analysis as claimed in claim 2, is characterized in that, described audio signal is the AC signal of amplitude 2mV-2V, frequency 300Hz-20kHz.
4. the automatic gain controller in a kind of audio signal analysis as claimed in claim 2, is characterized in that, described resistance R 1 is 50 kilo-ohms with R2 resistance, and R3 resistance is 1 kilo-ohm, capacitor C
ccapacitance is 0.1 microfarad, C
hcapacitance is 47 pico farads.
5. the automatic gain controller in a kind of audio signal analysis as claimed in claim 2, is characterized in that, described variable gain amplifier chip U1 is VCA810, and described operational amplifier chip U2 is OPA820, and described diode D1 is HP5082.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310542745.6A CN103580634A (en) | 2013-10-29 | 2013-10-29 | Automatic gain controller in audio signal analysis |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310542745.6A CN103580634A (en) | 2013-10-29 | 2013-10-29 | Automatic gain controller in audio signal analysis |
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| CN103580634A true CN103580634A (en) | 2014-02-12 |
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|---|---|---|---|
| CN201310542745.6A Pending CN103580634A (en) | 2013-10-29 | 2013-10-29 | Automatic gain controller in audio signal analysis |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103581800A (en) * | 2013-10-24 | 2014-02-12 | 厦门雅迅网络股份有限公司 | Device capable of preventing reverse connection of single-end audio input interface |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5107225A (en) * | 1990-11-30 | 1992-04-21 | Qualcomm Incorporated | High dynamic range closed loop automatic gain control circuit |
| CN201674469U (en) * | 2010-03-25 | 2010-12-15 | 上海沙丘微电子有限公司 | Audio-frequency power amplifier circuit with automatic gain control circuit |
-
2013
- 2013-10-29 CN CN201310542745.6A patent/CN103580634A/en active Pending
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5107225A (en) * | 1990-11-30 | 1992-04-21 | Qualcomm Incorporated | High dynamic range closed loop automatic gain control circuit |
| CN201674469U (en) * | 2010-03-25 | 2010-12-15 | 上海沙丘微电子有限公司 | Audio-frequency power amplifier circuit with automatic gain control circuit |
Non-Patent Citations (1)
| Title |
|---|
| BURR-BROWN PRODUCTS FROM TEXAS INSTRUMENTS: "《High Gain Adjust Range, Wideband, Voltage-Controlled Amplifier》", 31 December 2004, article "High Gain Adjust Range, Wideband, Voltage-Controlled Amplifier", pages: 1 - 12 * |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103581800A (en) * | 2013-10-24 | 2014-02-12 | 厦门雅迅网络股份有限公司 | Device capable of preventing reverse connection of single-end audio input interface |
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Application publication date: 20140212 |
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