Background technology
ASK（Amplitude Shift Keying, amplitude-shift keying）Wireless telecommunication system is widely used in remote keyless controlSystem, the field such as gate inhibition, the characteristics of with low cost, low in energy consumption, long transmission distance, simple application circuit.The ASK of complete set withoutLine control system includes transmitter and receiver two parts, as shown in figure 1, this two parts is generally individually present.In existing ASKIn the gain control structure of wireless receiver, there are two kinds of main implementations：
（1）Based on peakvalue's checking（PKD）Feedback controling mode, as shown in Figure 2.ASK based on peakvalue's checking wirelessly connectsReceipts machine structure includes low-noise amplifier（Low Noise Amplifier, referred to as " LNA "）, frequency mixer, wave filter, variable increasingBeneficial amplifier（Variable Gain Amplifier, referred to as " VGA "）, peak detector（PKD）And automatic gain controller（Automatic Gain Control, referred to as " AGC "）, wherein AGC and VGA, Mixer（Frequency mixer）Gain is formed to control backRoad.This gain control structure is that AGC modules are by demodulated signal amplitude by the signal input after demodulation to AGC modulesSize is compared with preset value, so that the discharge and recharge of electric capacity C1 is controlled, and the voltage on electric capacity C1 directly controls VGA and mixingThe gain of device, so as to realize automatic growth control.If amplitude exceedes preset value, by the C1 electric discharges of control electric capacity, on electric capacity C1Voltage reduction, link gain reduction；Otherwise it is then anti-.
（2）Based on received signal strength indicator（RSSI）Feedback controling mode, as shown in Figure 3.The program is equally usedClosed-loop feedback manner controls gain, and what its gain was controlled acts on LNA, and the loop of this gain control structure includes LNA,Mixer（Frequency mixer）, VGA, RSSI and AGC module.RSSI is input in AGC after receiving signal, is connect in AGC modulesThe signal of receipts is compared with preset value, so that the gain size of LNA is determined, if RSSI signals are more than preset value, by LNAIt is set to low gain mode；Otherwise it is then anti-.
But, when the distance of emitter and receiver changes, the signal that receiver antenna can sense is by synchronous changeChange.If quick regulation can not be carried out to whole receiver link gain, receiver signal will be caused to block（Signal is excessive）OrCannot receive（Signal is too small）, and then cause data packetloss.In scheme（1）In, the gain control the structure ring road response time compared withIt is long, it is impossible to enough carrier amplitude changes of tracking in time, so as to cause receiver to occur blocking or cannot connecing in input signal saltus stepReceive.
Equally, in scheme（2）In, the program is also adopted by closed-loop feedback manner control gain, and its gain control makes and is used forLNA, the loop of the gain control structure includes LNA, Mixer, AMP（Amplifier）, RSSI and AGC modules, the loop wrappedInclude module many, control time is long, be unfavorable for quick response.
Meanwhile, in scheme（2）In, whole link only exists two kinds of discrete gain modes of large-and small-signal, is unfavorable for linkThe continuously linear of gain is reconciled.
The content of the invention
It is an object of the invention to provide a kind of ASK wireless receivers and its auto gain control method so that ASK is wirelessReceiver is capable of the situation of the big signal of quick response or small-signal, while the continuously linear regulation to link gain can be realized.
In order to solve the above technical problems, the invention provides a kind of ASK wireless receivers, comprising：First order feedforward is automaticGain control module and second level feedback automatic growth control module；
Wherein, first order feedforward automatic growth control module is according to the amplitude of the radiofrequency signal received from antenna,To carrying out automatic growth control for carrying out the low-noise amplifier LNA of low noise amplification to the radiofrequency signal；
Control voltage of the second level feedback automatic growth control module according to produced by rear class dynamically adjusts describedThe gain amplifier through the useful signal after bandpass filter filtering interference signals of LNA outputs, the tune of output amplitude relative constancySignal processed；The modulated signal of the output is demodulated by complex demodulator；After the control voltage is according to the demodulationSignal is obtained.
Present invention also offers a kind of auto gain control method of ASK wireless receivers, comprise the steps of：
Radiofrequency signal is received from antenna；
The amplitude of the radiofrequency signal that first order feedforward automatic growth control module is received according to, to for describedThe low-noise amplifier LNA that radiofrequency signal carries out low noise amplification carries out automatic growth control；
It is defeated that control voltage of the second level feedback automatic growth control module according to produced by rear class dynamically adjusts the LNAThe gain amplifier through the useful signal after bandpass filter filtering interference signals for going out, the modulation letter of output amplitude relative constancyNumber；The modulated signal of the output is demodulated by complex demodulator；The control voltage is according to the signal after the demodulationObtain.
Embodiment of the present invention in terms of existing technologies, radio frequency is realized by first order feedforward automatic growth control moduleThe feedforward automatic growth control of front end, the feedback automatic gain of intermediate-frequency section is realized by second level feedback automatic growth control moduleControl.Because first order feedforward automatic growth control module can automatically will when the amplitude of input signal exceedes certain limitLNA is switched to low gain mode, conversely, when input signal amplitude is reduced to certain limit, LNA is switched into high-gain automaticallyPattern, whole process does not need rear class feedback signal, therefore greatly improves response speed, and this part is played to whole link gainCoarse adjustment is acted on.And it is that the control voltage according to produced by rear class dynamically adjusts amplification that automatic growth control module is fed back in the second levelGain, fine tuning effect is played to whole link gain.Automatically adjusting for fast gain is realized by two links so that ASKWireless receiver rapidly can be adjusted to whole receiver link gain, the feelings of the big signal of quick response or small-signalCondition, while the continuously linear regulation to link gain can be realized.
In addition, first order feedforward automatic growth control module is automatic gain controller AGC；Feed back automatic gain in the second levelControl module is variable gain amplifier VGA.Because AGC and VGA are existing ripe devices, it is ensured that embodiment party of the present inventionThe feasibility of formula.
In addition, the input of second level feedback automatic growth control module is connected with the output end of bandpass filter；It is describedThe output end of second level feedback automatic growth control module is connected with the complex demodulator；The output letter of the complex demodulatorNumber it is input in current controller, the current controller directly controls the discharge and recharge of an electric capacity；The control voltage is the electricityVoltage in appearance.Because intermediate frequency feeds back automatic gain control circuit by VGA, complex demodulator, current controller and electric capacity C mono-Rise and constitute, in the signal input that complex demodulator is detected to current controller, current controller directly controls electric capacity C charge and dischargesElectricity, the voltage on electric capacity C is applied directly in VGA.And communication data coding theory understands, last solution recalls the " high of dataLevel ", " low level " theoretical probability should be identical, therefore can with this signal opening come the charge pump in control electric current controllerOpen and close.If VGA gain is excessive, averagely demodulating the high level probability for coming will be excessive, therefore now charge pump controlElectric capacity discharges, and reduces its voltage, so as to reduce VGA gain until stabilization；, whereas if VGA gain is too small, then demodulate what is come" low level " probability will be less than normal, and now charge pump control electric capacity C charges, and raises electric capacity C voltage, so as to improve VGA gainUntil stabilization.Therefore, the closed gain control loop based on above-mentioned principle design can effectively combine the increasing that demodulation module controls VGABenefit, it is ensured that intermediate frequency feedback automatic gain control circuit can play fine tuning effect to whole link gain.
Specific embodiment
To make the object, technical solutions and advantages of the present invention clearer, below in conjunction with accompanying drawing to each reality of the inventionThe mode of applying is explained in detail.However, it will be understood by those skilled in the art that in each implementation method of the invention,In order that reader more fully understands the application and proposes many ins and outs.But, even if without these ins and outs and baseMany variations and modification in following implementation method, it is also possible to realize the application each claim technical side required for protectionCase.
First embodiment of the invention is related to a kind of ASK wireless receivers, concrete structure as shown in figure 4, the ASK is wirelessReceiver is included：Antenna, low-noise amplifier（LNA）, automatic gain controller（AGC）, frequency mixer（Mixer）, phaselocked loop（Phase Locked Loop, referred to as " PLL "）, bandpass filter（Band-pass filter, referred to as " BPF "）, variable gainAmplifier（VGA）, complex demodulator, current controller, electric capacity C and clock data restorer.
Wherein, AGC as the first order feedover automatic growth control module, according to the width of the radiofrequency signal received from antennaDegree, to carrying out automatic growth control for carrying out low noise amplification LNA to radiofrequency signal.As shown in figure 4, the input of the AGCIt is connected with antenna, output end is connected with the LNA.The AGC and LNA constitutes the feedforward automatic growth control electricity of radio frequency partRoad, works as input signal（The radiofrequency signal for being received from antenna）Amplitude exceed preset value when, LNA is switched to low gain by AGCPattern；Conversely, when input signal amplitude is less than preset value, LNA is switched to high gain mode by AGC.Whole process need notRear class feedback signal, is conducive to improving response speed, and the automatic growth control of the radio frequency part is played slightly to whole link gainTune is acted on.
In the present embodiment, the output termination frequency mixer of LNA, another input of frequency mixer terminates the defeated of phaselocked loopGo out end, the input of the output terminal strip bandpass filter of frequency mixer.That is, LNA by antenna detection to radiofrequency signal putGreatly, and it is input in Mixer, another input of Mixer is phaselocked loop（PLL）, the load required for the lower mixing of PLL generationsRipple signal.Mixer is by produced signal input to bandpass filter（BPF）In, BPF can be filtered outside useful signal frequency rangeInterference signal, in the signal input in channel to next stage VGA.VGA feeds back automatic growth control module, root as the second levelDynamically adjusted according to the control voltage produced by rear class and increased through the amplification of the useful signal after bandpass filter filtering interference signalsBenefit, the modulated signal of output amplitude relative constancy, the modulated signal of the output is demodulated by complex demodulator；Control electricityObtained according to the signal after the demodulation at all.
Specifically, the input of VGA is connected with the output end of bandpass filter, and output end is connected with complex demodulator,The output signal of complex demodulator is input in current controller, and the current controller directly controls the discharge and recharge of an electric capacity, controlVoltage processed is the voltage on electric capacity.The output signal of complex demodulator is by obtaining data-signal after clock data restorerAnd clock signal.
That is, the feedback that VGA, complex demodulator, current controller and electric capacity C constitute intermediate-frequency section together is automaticGain control circuit.To in current controller, current controller directly controls electric capacity C to the signal input that complex demodulator is detectedDischarge and recharge, the voltage on electric capacity C is applied directly in VGA.From communication data coding theory, last solution recalls dataThe theoretical probability of " high level ", " low level " should be identical, therefore can be with this signal come the charge pump in control electric current controllerOpening and closing.If VGA gain is excessive, averagely demodulating the high level probability for coming will be excessive, therefore now charge pumpControl electric capacity electric discharge, reduces its voltage, so as to reduce VGA gain until stabilization；, whereas if VGA gain is too small, then demodulate" low level " probability for coming will be less than normal, and now charge pump control electric capacity C charges, and raises electric capacity C voltage, so as to improve VGAGain is until stabilization.Closed gain control loop based on above-mentioned principle design can effectively combine the increasing that demodulation module controls VGABenefit.Fine tuning effect is played to whole link gain in this part.
Therefore, in the present embodiment, by two-stage gain-adjusted mechanism（The feedforward automatic growth control electricity of radio-frequency front-endRoad and the feedback automatic gain control circuit of intermediate-frequency section）Realize automatically adjusting for fast gain so that ASK wireless receiversIt is capable of the situation of the big signal of quick response or small-signal, while the continuously linear regulation to link gain can be realized, effectively increasesThe strong stability of design, more adapts to commercial Application.
And, it is automatic as second level feedback using VGA using AGC as first order feedforward automatic growth control moduleGain control module.Because AGC and VGA are existing ripe devices, it is ensured that the feasibility of embodiment of the present invention.
It is noted that each module involved in present embodiment is logic module, in actual applications, oneIndividual logic unit can be a part for a physical location, or a physical location, can also be with multiple physics listsThe combination of unit is realized.Additionally, in order to protrude innovative part of the invention, will not be with solution institute of the present invention in present embodimentThe unit that the technical problem relation of proposition is less close is introduced, but this is not intended that in present embodiment do not exist other listsUnit.
Second embodiment of the present invention is related to a kind of ASK wireless receivers.Second embodiment is in first embodimentRadix on made further refinement, give LNA, AGC, VGA, complex demodulator, current control in ASK wireless receiversThe concrete structure of device.
Specifically, as shown in figure 5, wherein, RFI is the radiofrequency signal of input to the circuit structure of the LNA with gain switching,RFOP, RFON are the radio-frequency differential signal of output, and VCS1, VCS2 are the bias voltage of folded tube M2, M5, and VB1, VB2 are amplificationThe DC offset voltage of pipe M3, M6, GCTL is gain switch-over control signal.
As shown in fig. 6, wherein, RFI is the radiofrequency signal of input to AGC part-structures in feedforward gain control circuit,GCTL is the gain control signal of output, and VBI is the bias voltage of radiofrequency signal, and VBC is the bias voltage of current source, and VBT isThe threshold voltage of comparator, the radiofrequency signal of input is by after first order caching, being input to rear class signal integration circuit, integration electricity, in comparator, the threshold voltage VBT with setting compares, and produces gain control signal for average control source produced by road.
VGA structures in feedback oscillator control circuit are as shown in Figure 7（Wherein I, in Q arbitrarily all the way）.Wherein, INM, INPIt is the differential signal of input, OUTM, OUTP are the differential signal of output, and VREF is common-mode feedback reference voltage, and VC is gain controlVoltage processed, VBP is bias voltage, and dotted line frame is common-mode feedback part.
As shown in figure 8, wherein, IP, IN, QP, QN are the orthogonal vector signal of VGA outputs to complex demodulator circuit structure,To after MN5~MN8, produced electric current includes a constant DC component and in addition to above-mentioned four tunnel signal input on MN2One AC compounent related to input signal amplitude, wherein direct current component can be offset by adjusting the electric current of MN4, thereforeThe electric current related to input signal amplitude is only existed in MP4~MP9, above-mentioned electric current is changed and BUF by OPA voltages to electric currentShaping after, form demodulated output signal DEM.
Current controller structure is as shown in figure 9, wherein, in current controller, DEM is the demodulated signal of input, and IB isInput reference current, OUT is exported for charge and discharge electric current.When DEM is high level, correspondence VGA now gains are larger, electric dischargeBranch road MN1, MN14 opening, electric capacity electric discharge, capacitance voltage declines；When DEM is low level, correspondence VGA now gains are smaller,Charging paths MP13, MN18 opening, electric capacity is charged, and capacitance voltage is raised, and said process forms a complete closed-loop control.
It is noted that LNA, AGC, VGA, complex demodulator, the specific knot of current controller in present embodimentStructure, simply a kind of concrete implementation mode, in actual applications, it would however also be possible to employ other equivalent circuit structures, differs hereinOne repeats.
Third embodiment of the invention is related to a kind of auto gain control method of ASK wireless receivers, and idiographic flow is such asShown in Figure 10.
In step 1001, ASK wireless receivers receive radiofrequency signal from antenna.
Then, in step 1002, first order feedforward automatic growth control module（Such as AGC）According to the radio frequency letter for receivingNumber amplitude, to carrying out automatic growth control for carrying out the LNA of low noise amplification to radiofrequency signal.Specifically, input is worked asSignal（The radiofrequency signal for being received from antenna）Amplitude exceed preset value when, LNA is switched to low gain mode by AGC；Conversely,When input signal amplitude is less than preset value, LNA is switched to high gain mode by AGC.Whole process does not need rear class feedback letterNumber, being conducive to improving response speed, the automatic growth control of the radio frequency part plays coarse adjustment effect to whole link gain.
In step 1003, second level feedback automatic growth control module（Such as VGA）Control electricity according to produced by rear classPressure dynamically adjusts the gain amplifier through the useful signal after bandpass filter filtering interference signals of the LNA outputs, outputThe modulated signal of amplitude relative constancy.The modulated signal of the output is demodulated by complex demodulator；The control voltageObtained according to the signal after the demodulation.
Specifically, by the radiofrequency signal output after amplification to frequency mixer, another input of frequency mixer is received LNAThe carrier signal of phaselocked loop output.Phaselocked loop produces lower carrier signal required for being mixed.Frequency mixer is defeated by produced signalEnter to BPF, the interference signal outside useful signal frequency range is filtered by BPF, in the signal input in channel to VGA.VGA is used asTwo grades feedback automatic growth control modules, the control voltage according to produced by rear class dynamically adjust filtered through bandpass filter it is dryThe gain amplifier of the useful signal after signal is disturbed, the modulated signal of output amplitude relative constancy, the modulated signal of the output is led toComplex demodulator is crossed to be demodulated.The output signal of complex demodulator also will enter into a current controller, the current controlDevice directly controls the discharge and recharge of an electric capacity, and control voltage is the voltage on electric capacity.
By using the opening and closing of the charge pump in the data control electric current controller that complex demodulator is demodulated.Such asFruit VGA gain is excessive, and averagely demodulating the high level probability for coming will be excessive, therefore now charge pump control electric capacity electric discharge, dropLow its voltage, so as to reduce VGA gain until stabilization；, whereas if VGA gain is too small, then " low level " come is demodulated generalRate will be less than normal, and now charge pump control electric capacity C charges, and raises electric capacity C voltage, so as to improve VGA gain until stabilization.BaseThe gain that demodulation module controls VGA can be effectively combined in the closed gain control loop of above-mentioned principle design.This part is to wholeIndividual link gain plays fine tuning effect.
It is seen that, present embodiment is the embodiment of the method corresponding with first embodiment, and present embodiment can be withFirst embodiment is worked in coordination implementation.The relevant technical details mentioned in first embodiment still have in the present embodimentEffect, in order to reduce repetition, repeats no more here.Correspondingly, the relevant technical details mentioned in present embodiment are also applicable inIn first embodiment.
It will be understood by those skilled in the art that the respective embodiments described above are to realize specific embodiment of the invention,And in actual applications, can to it, various changes can be made in the form and details, without departing from the spirit and scope of the present invention.