CN202550976U - Automatic gain control circuit - Google Patents
Automatic gain control circuit Download PDFInfo
- Publication number
- CN202550976U CN202550976U CN2012201712688U CN201220171268U CN202550976U CN 202550976 U CN202550976 U CN 202550976U CN 2012201712688 U CN2012201712688 U CN 2012201712688U CN 201220171268 U CN201220171268 U CN 201220171268U CN 202550976 U CN202550976 U CN 202550976U
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- amplifier
- gain amplifier
- control circuit
- variable gain
- signal
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- Expired - Fee Related
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Abstract
The utility model provides an automatic gain control circuit which comprises a variable gain amplifier connected with the system input end; the variable gain amplifier is an analogous variable gain amplifier; the output end of the analogous variable gain amplifier is connected with a fixed gain amplifier in series; and a detection circuit and an error amplifier are connected between the output end of the fixed gain amplifier and the gain control end of the analogous variable gain amplifier in parallel. The automatic gain control circuit has the beneficial effects that the amplitude of an output signal of the automatic gain control circuit is decided by a reference voltage signal and is kept constant; the saturation and/or the instability of a post-stage circuit when an input signal of a receiver is changed within a large scope can be avoided; and through changing the gain of a fixed amplifier in the automatic gain control circuit, a variable gain interval can be translated, and the gain change scope is not changed to facilitate the use in the application of different receivers.
Description
Technical field
The utility model is about a kind of automatic gain control circuit, but particularly relevant for the automatic gain control circuit between a kind of translation gain region.
Background technology
Fig. 1 is traditional automatic gain control circuit.Automatic gain control circuit comprises variable gain amplifier 110, testing circuit 120, error amplifier 130.Under automatic gain control is used; Peak detection circuit detects the output signal; And producing a peak detection signal, this peak detection signal of error amplifier amplifier and reference voltage also produce a control signal, this control signal control amplifier's gain.When peak detection signal was bigger than reference voltage, control signal reduced, thereby reduced amplifier's gain, and the output signal is reduced.
Yet; In the different received machine was used, the gain variation range of automatic gain control circuit changed and is little, and its constant interval is different; This just makes and all gets the constant interval that designs variable gain amplifier again at every turn, has reduced reliability when adding heavily to the difficulty of the work.
The utility model content
In view of this, the utility model provides a kind of automatic gain control circuit, and this control circuit need not to design again the constant interval of variable gain amplifier, has improved reliability when reducing work difficulty.
The purpose of the utility model realizes through following technical proposals.
A kind of automatic gain control circuit; Comprise the variable gain amplifier that links to each other with system input; Said variable gain amplifier is the analogue variable gain amplifier; Be connected in series with fixed gain amplifier at the analogue variable gain amplifier out, between the output of fixed gain amplifier and analogue variable gain amplifier gain control end, be connected in parallel to testing circuit and error amplifier.
The described automatic gain control circuit of the utility model, said analogue variable gain amplifier comprise three grades of analogue variable gain levels that are connected in series.
The described automatic gain control circuit of the utility model, said testing circuit comprise an amplitude detection circuit and a low pass filter.
The described automatic gain control circuit of the utility model, said system input input signal is an intermediate-freuqncy signal, input reference signal is 30MHz～50MHz.
The described automatic gain control circuit of the utility model, this analogue variable gain Amplifier Gain value range be-10dB～+ 50dB.
The analogue variable gain amplifier amplifies input differential signal, and its gain is determined by control signal VC and is continuous variable.Fixed gain amplifier amplifies the output signal of analogue variable gain amplifier, and its gain is fixing, plays the effect of translation variable gain scope.Testing circuit detects the amplitude of output signal, produces a detection signal, and this detection signal and reference voltage relatively produce control signal VC.Control signal is adjusted variable analog gain Amplifier Gain conversely.
The described automatic gain control circuit of the utility model; The amplitude of its output signal is by the reference voltage signal decision and keep constant; Cause late-class circuit saturated or unstable in the time of can avoiding receiver input signal wide variation; It is can the translation variable gain interval and do not change gain variation range, convenient use in the different received machine is used to change wherein fixedly Amplifier Gain.
Description of drawings
Fig. 1 is traditional automatic gain control circuit;
Fig. 2 is the automatic gain control circuit according to the utility model one embodiment;
Fig. 3 is the analogue variable gain amplifier that has more another embodiment of the utility model.
The simple declaration of symbol is following in the accompanying drawing:
110: variable gain amplifier; 120: testing circuit; 130: error amplifier; 210: the analogue variable gain amplifier; 220: fixed gain amplifier; 230: testing circuit; 240: error amplifier; A1, A2 ... An: analogue variable gain level; Input: input; Output: output; S11, S12: input signal; S13, S14: output signal; S15: detection signal; S21, S22: analogue variable gain amplifier input signal; S23, S24: analogue variable gain amplifier output signal; S25, S26: fixed gain amplifier output signal; S27: detection signal; S28: control signal; VREF: reference voltage signal.
Embodiment
For let the above-mentioned of the utility model and other purposes, feature and advantage can be more obviously understandable, the hereinafter spy enumerates preferred embodiment, and cooperates appended graphicly, elaborates as follows:
Fig. 2 shows the automatic gain control circuit of implementing according to the utility model one.Automatic gain control circuit comprises analogue variable gain amplifier 210, fixed gain amplifier 220, testing circuit 230 and error amplifier 240.Wherein, analogue variable gain amplifier 210 receives an input differential signal, adjusts this amplifier's gain to export a differential signal according to a control signal; Fixed gain amplifier 220 is coupled to said analogue variable gain amplifier 210, should output differential signal in order to receive, and amplify fixedly multiple to produce a differential output signal; Testing circuit 230 is coupled to said fixed gain amplifier 220, should export differential signal in order to receive, and the amplitude that detects this signal is to produce a detection signal; Error amplifier 240 is coupled to said testing circuit 230, produces in order to receive this detection signal and reference voltage, through amplifying to produce an analog control signal.
In the automatic gain control circuit of the utility model; 210 output Output are connected in series with fixed gain amplifier 220 at the analogue variable gain amplifier, between the output of fixed gain amplifier 220 and analogue variable gain amplifier 210 gain control ends, are connected in parallel to testing circuit 230 and error amplifier 240.
In the automatic gain control circuit of the utility model, system input Input input signal is an intermediate-freuqncy signal, and input reference signal is 30MHz～50MHz.
Analogue variable gain amplifier input signal S21 and S22 that analogue variable gain amplifier 210 receives from input Input; And with its amplification generation analogue variable gain amplifier output signal S23 and S24; Fixed gain amplifier 220 receives analogue variable gain amplifier output signal S23 and S24 and amplifies fixedly multiple; Produce fixed gain amplifier output signal S25 and S26 to export the Output end to; Testing circuit 230 receives the output signal and detects its amplitude, produces detection signal S27, and error amplifier 240 amplification detection signal S27 and reference voltage VREF produce control signal S28.
According to the utility model one embodiment, as shown in Figure 3, analogue variable gain amplifier 210 comprise a plurality of analogue variable gain level A1 that are connected in series, A2 ... An.Error amplifier S240 can be made up of at least one operational amplifier, so error amplifier S240 can amplification detection signal S27 and reference voltage VREF.For example: when the amplitude of fixed gain amplifier output signal S25 and S26 the time greater than reference voltage; Testing circuit S230 produces the amplitude that detection signal S27 promptly exports signal; Because this moment, detection signal amplitude S27 was greater than reference voltage, so the output signal of error amplifier S240, promptly control signal S28 can reduce; Thereby reduce the gain of analogue variable gain amplifier S210; Behind fixed gain amplifier S220, the amplitude of fixed gain amplifier output signal S25 and S26 is reduced, through after a while; Automatic gain control circuit 200 can be stabilized in a state, and promptly the amplitude of fixed gain amplifier output signal S25 and S26 equals reference voltage VREF.In like manner; When the amplitude of fixed gain amplifier output signal S25 and S26 during less than reference voltage; The amplitude of the detection signal S27 of testing circuit S230 makes the control signal S28 of generation increase also less than reference voltage behind error amplifier S240 amplification detection signal S27 and the reference voltage signal VREF, thus the gain that increases analogue variable gain amplifier S210; The amplitude of its analogue variable gain amplifier output signal S23 and S24 also increases; Behind fixed gain amplifier S220, the amplitude of fixed gain amplifier output signal S25 and S26 is increased, through after a while; Automatic gain control circuit 200 can be stabilized in a state, and promptly the amplitude of fixed gain amplifier output signal S25 and S26 equals reference voltage.This shows; And a low pass filter arranged in the testing circuit; The size variation that the output signal does not have a big instantaneous variation amount output signal is to be adjusted gain gradually and stablized by circuit, can avoid receiver input signal wide variation to cause late-class circuit saturated or unstable, thus the malfunction that causes.Wherein input signal can be that its frequency range of an intermediate-freuqncy signal is 30MHz～50MHz.
More than show and described principal character, basic principle and the advantage of the utility model automatic gain control circuit.More than be merely the preferable embodiment of the utility model; It is not the protection range that is used to limit the utility model; Therefore, any variation and the improvement done within all spirit and principle scopes at the utility model all should be included within the protection range of the utility model.
Claims (4)
1. automatic gain control circuit; Comprise the variable gain amplifier that links to each other with system input; It is characterized in that; Said variable gain amplifier is the analogue variable gain amplifier, is connected in series with fixed gain amplifier at the analogue variable gain amplifier out, between the output of fixed gain amplifier and analogue variable gain amplifier gain control end, is connected in parallel to testing circuit and error amplifier.
2. a kind of automatic gain control circuit according to claim 1 is characterized in that, said analogue variable gain amplifier comprises a plurality of analogue variable gain levels that are connected in series.
3. a kind of automatic gain control circuit according to claim 1 is characterized in that, said testing circuit comprises an amplitude detection circuit and a low pass filter.
4. a kind of automatic gain control circuit according to claim 1 is characterized in that, said system input input signal is an intermediate-freuqncy signal, and input reference signal is 30MHz～50MHz.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2012201712688U CN202550976U (en) | 2012-04-20 | 2012-04-20 | Automatic gain control circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2012201712688U CN202550976U (en) | 2012-04-20 | 2012-04-20 | Automatic gain control circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN202550976U true CN202550976U (en) | 2012-11-21 |
Family
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2012201712688U Expired - Fee Related CN202550976U (en) | 2012-04-20 | 2012-04-20 | Automatic gain control circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN202550976U (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107332529A (en) * | 2017-06-09 | 2017-11-07 | 烽火通信科技股份有限公司 | A kind of automatic gain control circuit for fully differential trans-impedance amplifier |
| US10079584B1 (en) | 2017-03-14 | 2018-09-18 | Futurewei Technologies, Inc. | Closed-loop automatic gain control in linear burst-mode transimpedance amplifier |
-
2012
- 2012-04-20 CN CN2012201712688U patent/CN202550976U/en not_active Expired - Fee Related
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US10079584B1 (en) | 2017-03-14 | 2018-09-18 | Futurewei Technologies, Inc. | Closed-loop automatic gain control in linear burst-mode transimpedance amplifier |
| WO2018166386A1 (en) * | 2017-03-14 | 2018-09-20 | Huawei Technologies Co., Ltd. | Closed-loop automatic gain control in linear burst-mode transimpedance amplifier |
| CN107332529A (en) * | 2017-06-09 | 2017-11-07 | 烽火通信科技股份有限公司 | A kind of automatic gain control circuit for fully differential trans-impedance amplifier |
| CN107332529B (en) * | 2017-06-09 | 2021-02-09 | 烽火通信科技股份有限公司 | Automatic gain control circuit for fully differential trans-impedance amplifier |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C56 | Change in the name or address of the patentee |
Owner name: XI'AN AEROSPACE HUAXUN TECHNOLOGY CO., LTD. Free format text: FORMER NAME: XIAN HUAXUN MICROELECTRONIC CO., LTD. |
|
| CP03 | Change of name, title or address |
Address after: 710075 hi tech Zone, Shaanxi, Xi'an province 58, No. three, Hui International three floor Patentee after: XI'AN AEROSPACE HUAXUN TECHNOLOGY CO., LTD. Address before: 710075, Xi'an hi tech Zone, Shaanxi Province three science and Technology Road 58, Hao Hui International third floor Patentee before: Xian Huaxun Microelectronic Co., Ltd. |
|
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20121121 Termination date: 20200420 |
|
| CF01 | Termination of patent right due to non-payment of annual fee |