CN203278749U - Low noise amplifier with automatic level control circuit - Google Patents
Low noise amplifier with automatic level control circuit Download PDFInfo
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- CN203278749U CN203278749U CN 201320236005 CN201320236005U CN203278749U CN 203278749 U CN203278749 U CN 203278749U CN 201320236005 CN201320236005 CN 201320236005 CN 201320236005 U CN201320236005 U CN 201320236005U CN 203278749 U CN203278749 U CN 203278749U
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- low noise
- amplifying circuit
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Abstract
The utility model discloses a low noise amplifier with an automatic level control circuit. The low noise amplifier with the automatic level control circuit comprises three levels of amplifying circuits, a coupler, a wave detector, a comparator and a voltage control attenuator. The voltage control attenuator is connected between the second-level amplifying circuit and the third-level amplifying circuit in a series mode, the output end of the third-level amplifying circuit is connected with the input end of the coupler, and the output end of the coupler is connected with the input end of the wave detector. The output end of the wave detector is connected with the input end of the comparator, and the output end of the comparator is connected with the voltage control attenuator. According to the low noise amplifier with the automatic level control circuit, when an input signal level changes a lot, an output signal of the amplifier is a constant level value relative to a constant power value in the frequency bandwidth, in addition, the gain adjustable range is large, the potential risks of distortion and circuit damage are effectively solved, meanwhile, improving the circuit can be more convenient and more fast, and the low noise amplifier with the automatic level control circuit can be widely applied to various communication systems.
Description
Technical field
The utility model relates to a kind of amplifier, relates in particular to a kind of low noise amplifier with automatic level control circuit.
Background technology
Automatic electric-level is controlled (automatic level control, ALC) function of system's realization is: when larger variation occurs incoming signal level, keeping output signal is that a level value is invariable, namely very large when input power difference in the certain frequency bandwidth or when altering a great deal on a certain frequency, after the automatic electric-level control system, can keep output signal is a relatively constant performance number in this frequency bandwidth.The ALC technology is to adopt negative feedback mode formation closed loop loop that amplitude or the power of signal are automatically adjusted in system, makes the amplitude of signal or power become more steady, to reach constant.This shows, the automatic electric-level control system is widely used in communication transmitter, signal source and various measuring instrument, and ALC system also direct relation the indexs such as power flatness, power stability, power accuracy and power output dynamic range of system.In radio communication, effectively ride gain is a vital problem, the signal power that can direct relation next stage circuit receive appointment guarantees normal operation, commonly in communication system, amplifier itself is designed as biasing networks etc. at present, to amplifier gain amount adjustable extent less, also easily burn device and have risk.Level control system does not the earliest have feedback control loop, can not form closed loop, and just series connection variable gain amplifier or variable attenuator on primary link are regulated power on link by these devices.
The utility model content
The utility model purpose is exactly in order to make up the defective of prior art, a kind of low noise amplifier with automatic level control circuit to be provided.
The utility model is achieved through the following technical solutions:
A kind of low noise amplifier with automatic level control circuit, include three-stage amplifier, coupler, wave detector, comparator and voltage-controlled attenuator, described voltage-controlled attenuator is connected between second level amplifying circuit and third level amplifying circuit, the input of the output butt coupling device of described third level amplifying circuit, the input of the output tie geophone of coupler, the output of wave detector connects the input of comparator, and the output of comparator connects described voltage-controlled attenuator.
The crystal amplifier tube of first order amplifying circuit is field effect transistor ATF-34143, and adds resistance in parallel on the grid of being on the scene effect pipe ATF-34143, adds negative feedback on source electrode; Second level amplifying circuit and third level amplifying circuit all adopt the monolithic amplifier tube to carry out the signal amplification.
Described coupler adopts the parallel coupled line coupler; Described wave detector is that radio-frequency power detects control chip AD8314; Described comparator adopts dual operational amplifier LM2904; The PI type electrically controlled attenuator of described voltage-controlled attenuator for being consisted of by PIN diode.
The utility model has the advantages that: when the utility model when incoming signal level, larger variation occurs, the hold amplifier output signal is that a relatively constant performance number is that a level value is constant in this frequency bandwidth, and the gain adjustable extent is large, effectively solve the potential hazard that distortion and circuit damage, it is more convenient simultaneously circuit to be improved, and can be widely used in various communication systems.
Description of drawings
Fig. 1 is electrical block diagram of the present utility model.
Fig. 2 is low noise amplifier first order structure chart of the present utility model.
Fig. 3 is coupler structure figure of the present utility model.
Fig. 4 is voltage-controlled attenuator circuit diagram of the present utility model.
Embodiment
As shown in Figure 1, a kind of low noise amplifier with automatic level control circuit, include three-stage amplifier, coupler 1, wave detector 2, comparator 3 and voltage-controlled attenuator 4, described voltage-controlled attenuator 4 is connected between second level amplifying circuit 5 and third level amplifying circuit 6, the input of the output butt coupling device 1 of described third level amplifying circuit 6, the input of the output tie geophone 2 of coupler 1, the output of wave detector 2 connects the input of comparator 3, and the output of comparator 3 connects described voltage-controlled attenuator 4.
The crystal amplifier tube of first order amplifying circuit 7 is field effect transistor ATF-34143, and adds resistance in parallel on the grid of being on the scene effect pipe ATF-34143, adds negative feedback on source electrode; Second level amplifying circuit 5 and third level amplifying circuit 6 all adopt the monolithic amplifier tube to carry out the signal amplification.
Described coupler 1 adopts the parallel coupled line coupler; Described wave detector 2 detects control chip AD8314 for radio-frequency power; Described comparator 3 adopts dual operational amplifier LM2904; The PI type electrically controlled attenuator of described voltage-controlled attenuator 4 for being consisted of by PIN diode.
The realization of alc circuit must have a voltage (or electric current and voltage) that changes with extraneous signal intensity, and then the gain of removing the correlation level amplifier in the control system link by this voltage (or electric current).Alc circuit is actually a kind of in feedback control circuit, adopts degenerative operation principle, generally can be divided into gain controlled amplifying circuit and control voltage forming circuit two parts.
As shown in Figure 1, Vr is reference voltage, can control power output Po by the size that changes Vr, and gain controlled amplifying circuit is positioned at forward and amplifies path, and its gain changes with controlling voltage.The basic element of character of controlling voltage forming circuit is wave detector and comparator.The output signal of link is Po, and the coupling unit signal produces a magnitude of voltage Vo through the wave detector detection, compares with the Vr that sets, and produces the voltage Vc in order to ride gain controlled amplification device.When input signal Pi increased, Vo and Vc also increased thereupon.And as a negative feedback network, Vc increases the gain that makes amplifying circuit and descends, thereby the variable quantity that makes output signal reaches significantly less than the variable quantity of input signal the purpose that automatic gain is controlled.That is to say, the groundwork principle of alc circuit is that the gradual voltage of direct current with reaction signal changes in amplitude trend removes to control voltage-controlled attenuator, to reach the purpose of controlling output level.Wherein coupler adopts the parallel coupled line coupler, and the signal of coupling produces a voltage through the wave detector detection, and comparator adopts dual operational amplifier LM2904, and an amplifier realizes the function of subtraction circuit, guarantees the large control voltage of small-signal output; The another one amplifier realizes that homophase amplifies, and can realize correct voltage control by regulator potentiometer, and then to the voltage-controlled attenuator control that gains.
As shown in Figure 2, the field effect transistor ATF-34143 that chooses not is absolute stability in full frequency band, the unstable possibility that vibration is still arranged of the outer certain limit of band.Improve the amplifier self stability and can take several different methods, as series impedance negative feedback method, ferrite isolator method and resistive damped method etc.The method that adopts grid to add impedance in parallel in this design and add the source negative feedback microstrip line realizes that the circuit full frequency band stablizes.
As shown in Figure 3, the capable oriented coupler of coupler wire design of making even, this coupler is made of main line and subordinate line, and two parallel lines Microstrip Length are quarter-wave.When main line has alternating current to flow through, because two lines are mutually close, just be coupled with energy in subordinate line, coupling energy is not only by electric field but also pass through magnetic Field Coupling.Coupling by coupling capacitance causes couple current at subordinate line.Due to the effect of alternating magnetic field, according to the faradic direction of law of electromagnetic induction judgement, and then can determine each port energy output situation simultaneously.Consider overall dimensions and design objective, little band is directly chosen 50 impedance lines, by software optimization spacing and length, finally determines size.
As shown in Figure 4, voltage-controlled attenuator adopts PIN diode to design as attenuating elements, and they have low-down distortion, and only need less bias current, so than being more suitable for radio-frequency (RF) communication system.This attenuator is by the resistance PI type attenuator development of classics, three resistance are replaced with four PIN diode, this causes the asymmetric of network, biasing circuit also can be complicated, and then the PIN diode that makes series connection has improved the maximum that decays and also under certain attenuation, upper frequency limit has been doubled with two replacements.The series resistance of duo-diode has 180 degree phase differences simultaneously, can offset the even distortion.The parameter of the build-out resistor around suitably selecting.Can be in large dynamic attenuation range series connection and bypass diode correct biasing and shunting is provided, make the good impedance matching of whole network acquisition.
Claims (3)
1. low noise amplifier with automatic level control circuit, it is characterized in that: include three-stage amplifier, coupler, wave detector, comparator and voltage-controlled attenuator, described voltage-controlled attenuator is connected between second level amplifying circuit and third level amplifying circuit, the input of the output butt coupling device of described third level amplifying circuit, the input of the output tie geophone of coupler, the output of wave detector connects the input of comparator, and the output of comparator connects described voltage-controlled attenuator.
2. the low noise amplifier with automatic level control circuit according to claim 1, it is characterized in that: the crystal amplifier tube of first order amplifying circuit is field effect transistor ATF-34143, and add resistance in parallel on the grid of being on the scene effect pipe ATF-34143, add negative feedback on source electrode; Second level amplifying circuit and third level amplifying circuit all adopt the monolithic amplifier tube to carry out the signal amplification.
3. the low noise amplifier with automatic level control circuit according to claim 1, is characterized in that: described coupler employing parallel coupled line coupler; Described wave detector is that radio-frequency power detects control chip AD8314; Described comparator adopts dual operational amplifier LM2904; The PI type electrically controlled attenuator of described voltage-controlled attenuator for being consisted of by PIN diode.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201320236005 CN203278749U (en) | 2013-05-03 | 2013-05-03 | Low noise amplifier with automatic level control circuit |
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| Application Number | Priority Date | Filing Date | Title |
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| CN 201320236005 CN203278749U (en) | 2013-05-03 | 2013-05-03 | Low noise amplifier with automatic level control circuit |
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Cited By (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103888088A (en) * | 2014-03-20 | 2014-06-25 | 京信通信系统（广州）有限公司 | Power amplifier protection system based on ALC |
| CN105634428A (en) * | 2015-12-31 | 2016-06-01 | 中国石油天然气集团公司 | Automatic gain control system and control method for AGC (Automatic Gain Control) loop |
| WO2016172913A1 (en) * | 2015-04-30 | 2016-11-03 | 中国科学院微电子研究所 | Negative-feedback based power amplifier structure |
| CN106571786A (en) * | 2016-11-10 | 2017-04-19 | 电子科技大学 | Broadband double-balanced large dynamic automatic gain control circuit |
| CN107733371A (en) * | 2017-10-26 | 2018-02-23 | 成都西井科技有限公司 | The voltage-controlled attenuator circuit of highly attenuating value |
| CN107846198A (en) * | 2017-10-26 | 2018-03-27 | 成都西井科技有限公司 | low-loss power amplifying device |
| CN109217949A (en) * | 2017-06-29 | 2019-01-15 | 广州极飞科技有限公司 | Wireless communication apparatus and unmanned vehicle |
| CN109444759A (en) * | 2018-12-21 | 2019-03-08 | 成都前锋电子仪器有限责任公司 | A kind of accumulator internal resistance measuring system |
| CN113391573A (en) * | 2020-03-12 | 2021-09-14 | 中国移动通信集团河北有限公司 | Signal processing circuit |
| CN114124008A (en) * | 2021-11-12 | 2022-03-01 | 中国电子科技集团公司第二十九研究所 | Broadband self-adaptive AGC circuit and assembling method thereof |
| CN116436424A (en) * | 2023-06-14 | 2023-07-14 | 中星联华科技（北京）有限公司 | Automatic gain control circuit and control method thereof |
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2013
- 2013-05-03 CN CN 201320236005 patent/CN203278749U/en not_active Expired - Fee Related
Cited By (16)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103888088B (en) * | 2014-03-20 | 2017-03-08 | 京信通信系统（广州）有限公司 | Power amplifier protection system based on ALC |
| CN103888088A (en) * | 2014-03-20 | 2014-06-25 | 京信通信系统（广州）有限公司 | Power amplifier protection system based on ALC |
| WO2016172913A1 (en) * | 2015-04-30 | 2016-11-03 | 中国科学院微电子研究所 | Negative-feedback based power amplifier structure |
| CN105634428A (en) * | 2015-12-31 | 2016-06-01 | 中国石油天然气集团公司 | Automatic gain control system and control method for AGC (Automatic Gain Control) loop |
| CN106571786B (en) * | 2016-11-10 | 2019-08-13 | 电子科技大学 | A kind of broadband double flat weighing apparatus Larger Dynamic automatic gain control circuit |
| CN106571786A (en) * | 2016-11-10 | 2017-04-19 | 电子科技大学 | Broadband double-balanced large dynamic automatic gain control circuit |
| CN109217949B (en) * | 2017-06-29 | 2022-08-16 | 广州极飞科技股份有限公司 | Wireless communication device and unmanned vehicles |
| CN109217949A (en) * | 2017-06-29 | 2019-01-15 | 广州极飞科技有限公司 | Wireless communication apparatus and unmanned vehicle |
| CN107846198A (en) * | 2017-10-26 | 2018-03-27 | 成都西井科技有限公司 | low-loss power amplifying device |
| CN107733371A (en) * | 2017-10-26 | 2018-02-23 | 成都西井科技有限公司 | The voltage-controlled attenuator circuit of highly attenuating value |
| CN109444759A (en) * | 2018-12-21 | 2019-03-08 | 成都前锋电子仪器有限责任公司 | A kind of accumulator internal resistance measuring system |
| CN113391573A (en) * | 2020-03-12 | 2021-09-14 | 中国移动通信集团河北有限公司 | Signal processing circuit |
| CN113391573B (en) * | 2020-03-12 | 2023-10-27 | 中国移动通信集团河北有限公司 | signal processing circuit |
| CN114124008A (en) * | 2021-11-12 | 2022-03-01 | 中国电子科技集团公司第二十九研究所 | Broadband self-adaptive AGC circuit and assembling method thereof |
| CN116436424A (en) * | 2023-06-14 | 2023-07-14 | 中星联华科技（北京）有限公司 | Automatic gain control circuit and control method thereof |
| CN116436424B (en) * | 2023-06-14 | 2023-10-03 | 中星联华科技（北京）有限公司 | Automatic gain control circuit and control method thereof |
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Legal Events
| Date | Code | Title | Description |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20131106 Termination date: 20200503 |