The circuit structure of receiver dynamic range is improved based on reverse phase cancellation mechanismTechnical field
The present invention relates to signal analysis field more particularly to receiver signal analysis technical field, in particular to a kind of basesThe circuit structure of receiver dynamic range is improved in reverse phase cancellation mechanism.
Background technique
Receiver is middle widely used device, and effect is to receive signal, carries out the analysis, measurement, information of signal alsoOriginal etc..According to the Technical Architecture of receiver, superhet and zero intermediate frequency reciver etc. can be divided into.Wherein, the most commonly used isSuperhet, its main feature is that working frequency range is wide, high sensitivity.Typical receiver architecture is as shown in Figure 1.
Its working principle is that input signal be down-converted on a fixed intermediate frequency signal, subsequent progress ADC and phaseOFF signal processing, has extracted relevant information.The considerations of this super-heterodyne architecture is because of factors such as working frequency range, the bandwidth of system becomeFrequency series has 1~4 grade and differs.With increasing for series, internal amplification, filter circuit are also required to increase accordingly, circuit knotStructure is extremely complex.The addition of a large amount of analog devices keeps the dynamic range design comparison of system difficult.Under certain applications,It is some small-signals that system, which needs the useful information of reception and analysis, and there are some around the frequency range of these small-signalsStrong signal, and strong signal is that system is unconcerned.For example, Radar Doppler back wave is deposited in the sideband of high-power transmitting signalOn, there are high-intensitive other operator's base station signals etc. around highly sensitive wireless communication module.
In order to realize that the signal under the above scene receives, existing various receiver technical solutions are mainly penetrated from simulationFrequency channel is started with, and uses some means and measure, mainly has:
(1) system front end carries out the separation of large-and small-signal by filter.This mode is most direct, but to filterIt is more demanding, especially signal frequency it is closely spaced in the case where, the method is invalid.
(2) it optimizes hardware circuit design, carries out reasonable gain distribution, the circuits such as amplifier, frequency mixer are optimized and are setMeter, improves the performance indicator of the linearity, but the hardware design difficulty of this mode is big, and degree of optimization is limited.
In conclusion the technical solution of existing receiver, to presence and the high reject signal near small signal frequency, ifThe amplitude of this high reject signal has reached mission nonlinear working range, and channel will generate various nonlinearity products, thus shadowRing the parsing of small signal.
Summary of the invention
The purpose of the present invention is overcoming the above-mentioned prior art, provides a kind of satisfaction and automatically track, support automaticallyDisappear, the circuit structure applied widely that receiver dynamic range is improved based on reverse phase cancellation mechanism.
To achieve the goals above, the circuit structure of the invention that receiver dynamic range is improved based on reverse phase cancellation mechanismIt is as follows:
The circuit structure that receiver dynamic range is improved based on reverse phase cancellation mechanism of the invention, is mainly characterized by, instituteThe circuit structure stated includes:
The output end of preselection filter module, the preselection filter module is connected with power splitter, for filtering out thisSignal except machine；
Detect receiving channel module, the input terminal of the detection receiving channel module and the preselection filter moduleOutput end be connected, for extracting the strong signal in channel；
Offset channel module, the output of the input terminal of the counteracting channel module and the detection receiving channel moduleEnd is connected, for generating offseting signal；
Receiver channel module, the input terminal of the receiver channel module and the preselection filter module and is supportedThe output end of channel module of disappearing is connected, for handling the signal by channel.
Preferably, the detection receiving channel module includes:
The input terminal of first frequency mixer, first frequency mixer is connected with the output end of the power splitter, is used forRadiofrequency signal is converted to intermediate-freuqncy signal；
First bandpass filter, the output end of the input terminal of first bandpass filter and first frequency mixerIt is connected, it is anti-aliasing for carrying out；
First A-D converter, the input terminal of first A-D converter are defeated with first bandpass filterOutlet is connected, for analog if signal to be transformed into digital signal；
First digital down converter, the input terminal of first digital down converter and first A-D converterOutput end be connected, for translating the signals into i/q signal；
First bandwidth control units, the input terminal of first bandwidth control units and first Digital Down ConvertThe output end of device is connected, and the output end of first bandwidth control units is connected with the counteracting channel module, usesIn the bandwidth and frequency that select quasi- offseting signal.
Preferably, the counteracting channel module includes:
Digital up converter, the output of the input terminal of the digital up converter and the detection receiving channel moduleEnd is connected, for translating the signals into digital medium-frequency signal；
Digital delaying circuit unit, the input terminal of the digital delaying circuit unit and the digital up converterOutput end is connected, and is used for finely regulating signal phase；
Digital-to-analog converter, the output end phase of the input terminal of the digital-to-analog converter and the digital delaying circuit unitConnection, for converting digital signals into analog signal；
Low-pass filter, the input terminal of the low-pass filter are connected with the output end of the digital-to-analog converter,For filtering out high frequency clock signal, and generate equal in magnitude with original signal and opposite in phase analog intermediate frequency signal.
Preferably, the counteracting channel module further includes the second frequency mixer, the input terminal of second frequency mixer withThe output end of the low-pass filter is connected, for converting the signal into radio frequency band.
Preferably, the receiver channel module includes:
Time delay circuit unit, the input terminal of the time delay circuit unit are connected with the output end of the power splitter,For being delayed to analog signal；
Summing circuit unit, the output end of the input terminal of the summing circuit unit and the time delay circuit unit andThe output end for offsetting the second frequency mixer of channel module is connected, for original reception signal and the progress of transformed signalSum operation；
Third frequency mixer, the input terminal of the third frequency mixer are connected with the output end of the summing circuit unitIt connects, for carrying out frequency conversion to radiofrequency signal；
Second bandpass filter, the output end of the input terminal of second bandpass filter and the third frequency mixerIt is connected, it is anti-aliasing for carrying out；
Second A-D converter, the input terminal of second A-D converter are defeated with second bandpass filterOutlet is connected, for analog signal to be transformed into digital signal；
Second digital down converter, the input terminal of second digital down converter and second A-D converterOutput end be connected, for translating the signals into i/q signal.
Preferably, the bandwidth of first bandwidth control units is controlled by circuit structure.
Preferably, the detection receiving channel module and receiver channel module share local oscillation signal.
Preferably, the frequency difference of first digital down converter and the second digital down converter is strong and weak signalsFrequency difference.
Preferably, the detection receiving channel module further includes the first local oscillator unit, the first local oscillator unitOutput end is connected with the input terminal of first frequency mixer.
Preferably, the counteracting channel module further includes the second local oscillator unit, the output of the second local oscillator unitEnd is connected with the input terminal of the input terminal of second frequency mixer and third frequency mixer simultaneously.
Preferably, the output end of the first local oscillator unit is also connected with the input terminal of the third frequency mixer.
Using the circuit structure of the invention for improving receiver dynamic range based on reverse phase cancellation mechanism, believed by radio frequencyNumber offset method, realize strong jamming in the case of, the small received validity of signal.Have the advantage that (1) passes through counteracting machineSystem, can effectively inhibit high reject signal present in channel, to realize measurement analysis of small signal etc., identical circuitStructure substantially increases the linear dynamic range of system, by this method, at least improvement Dynamic Range 20dB, passes throughUp to 30~35dB after fine adjustment.(2) the method is especially suitable for the closely spaced signal processing of signal frequency, and before this, it is rightIt handles extremely difficult in the interference signal in this band or even cannot achieve.(3) interval of offseting signal and bandwidth are allIt is program-controlled and automatically track, it is easy to use.(4) this programme has certain scalability, can increase sense channel quantity, realNow cross application existing for a high reject signal.
Detailed description of the invention
Fig. 1 is the typical superhet block diagram of the prior art.
Fig. 2 is the schematic diagram of the circuit structure of the invention that receiver dynamic range is improved based on reverse phase cancellation mechanism.
Fig. 3 is the monitoring and reception of the circuit structure of the invention that receiver dynamic range is improved based on reverse phase cancellation mechanismThe signal processing schematic diagram in channel.
Fig. 4 is the embodiment one of the circuit structure of the invention that receiver dynamic range is improved based on reverse phase cancellation mechanismThe improved broadband cancellation scheme schematic diagram of scheme.
Fig. 5 is the embodiment two of the circuit structure of the invention that receiver dynamic range is improved based on reverse phase cancellation mechanismThe improvement project schematic diagram of offseting signal is generated using high-speed DAC.
Appended drawing reference:
The first frequency mixer of Mixer1
The first bandpass filter of BPF1
The first A-D converter of ADC1
The first digital down converter of DDC1
The first bandwidth control units of BWC
DUC digital up converter
DDL digital delaying circuit unit
LPF low-pass filter
The second frequency mixer of Mixer3
DL time delay circuit unit
Mixer2 third frequency mixer
The second bandpass filter of BPF2
The second A-D converter of ADC2
The second digital down converter of DDC2
LO1 the first local oscillator unit
LO2 the second local oscillator unit
Specific embodiment
It is further to carry out combined with specific embodiments below in order to more clearly describe technology contents of the inventionDescription.
The circuit structure that receiver dynamic range is improved based on reverse phase cancellation mechanism of the invention, wherein the circuitStructure includes:
The output end of preselection filter module, the preselection filter module is connected with power splitter, for filtering out thisSignal except machine；
Detect receiving channel module, the input terminal of the detection receiving channel module and the preselection filter moduleOutput end be connected, for extracting the strong signal in channel；
Offset channel module, the output of the input terminal of the counteracting channel module and the detection receiving channel moduleEnd is connected, for generating offseting signal；
Receiver channel module, the input terminal of the receiver channel module and the preselection filter module and is supportedThe output end of channel module of disappearing is connected, for handling the signal by channel.
As the preferred embodiment of the present invention, the detection receiving channel module includes:
First frequency mixer Mixer1, the output end of the input terminal of the first frequency mixer Mixer1 and the power splitterIt is connected, for radiofrequency signal to be converted to intermediate-freuqncy signal；
First bandpass filter BPF1, the input terminal of the first bandpass filter BPF1 and first frequency mixerThe output end of Mixer1 is connected, anti-aliasing for carrying out；
First A-D converter ADC1, the input terminal of the first A-D converter ADC1 and first band logical are filteredThe output end of wave device BPF1 is connected, for analog if signal to be transformed into digital signal；
First digital down converter DDC1, the input terminal of the first digital down converter DDC1 and first mouldThe output end of A/D converter ADC1 is connected, for translating the signals into i/q signal；
First bandwidth control units BWC, the input terminal of the first bandwidth control units BWC and first numberThe output end of low-converter DDC1 is connected, the output end of the first bandwidth control units BWC and the counteracting channelModule is connected, for selecting the bandwidth and frequency of quasi- offseting signal.
As the preferred embodiment of the present invention, the counteracting channel module includes:
Digital up converter DUC, the input terminal of the digital up converter DUC and the detection receiving channel moduleOutput end be connected, for translating the signals into digital medium-frequency signal；
Digital up converter DDL, the input terminal of the digital up converter DDL and the digital up converter DUCOutput end be connected, be used for finely regulating signal phase；
Digital-to-analog converter, the output end phase of the input terminal of the digital-to-analog converter and the digital up converter DDLConnection, for converting digital signals into analog signal；
The output end phase of the input terminal and the digital-to-analog converter of low-pass filter LPF, the low-pass filter LPFConnection for filtering out high frequency clock signal, and generates equal in magnitude with original signal and opposite in phase analog intermediate frequency signal.
As the preferred embodiment of the present invention, the counteracting channel module further includes the second frequency mixer Mixer3, instituteThe input terminal of the second frequency mixer Mixer3 stated is connected with the output end of the low-pass filter LPF, for becoming signalIt changes on radio frequency band.
As the preferred embodiment of the present invention, the receiver channel module includes:
Time delay circuit unit DL, the input terminal of the time delay circuit unit DL are connected with the output end of the power splitterIt connects, for being delayed to analog signal；
Summing circuit unit, the output end of the input terminal of the summing circuit unit and the time delay circuit unit DLIt is connected with the output end of the second frequency mixer Mixer3 for offsetting channel module, for original reception signal and transformedSignal carries out sum operation；
Third frequency mixer Mixer2, the input terminal of the third frequency mixer Mixer2 and the summing circuit unitOutput end is connected, for carrying out frequency conversion to radiofrequency signal；
Second bandpass filter BPF2, the input terminal of the second bandpass filter BPF2 and the third frequency mixerThe output end of Mixer2 is connected, anti-aliasing for carrying out；
Second A-D converter ADC2, the input terminal of the second A-D converter ADC2 and second band logical are filteredThe output end of wave device BPF2 is connected, for analog signal to be transformed into digital signal；
Second digital down converter DDC2, the input terminal of the second digital down converter DDC2 and second mouldThe output end of A/D converter ADC2 is connected, for translating the signals into i/q signal.
As the preferred embodiment of the present invention, the bandwidth of the first bandwidth control units BWC is by circuit structure controlSystem.
As the preferred embodiment of the present invention, the detection receiving channel module and receiver channel module share thisShake signal.
As the preferred embodiment of the present invention, the first digital down converter DDC1 and the second digital down converterThe frequency difference of DDC2 is the frequency difference of strong and weak signals.
As the preferred embodiment of the present invention, the detection receiving channel module further includes the first local oscillator unit LO1,The output end of the first local oscillator unit LO1 is connected with the input terminal of the first frequency mixer Mixer1.
As the preferred embodiment of the present invention, the counteracting channel module further includes the second local oscillator unit LO2, describedThe output end of the second local oscillator unit LO2 and the input terminal of the second frequency mixer Mixer3 and third frequency mixer Mixer2Input terminal is connected.
As the preferred embodiment of the present invention, the output end of the first local oscillator unit LO1 also with the thirdThe input terminal of frequency mixer Mixer2 is connected.
In a specific embodiment of the invention, system block diagram of the invention and connection relationship are as shown in Fig. 2, receiver is penetratedFrequency input first passes around preselection filter module, the signal except the machine is filtered out, subsequently into a power splitter, later, systemIt is divided into 3 channels, is to detect receiving channel module, receiver channel module and the counteracting channel mould for generating offseting signal respectivelyBlock.The output all the way of power splitter enters detection receiving channel module, which is mainly the strong signal extracted in channel, withThe process flow of receiver channel module is similar, is to be transformed into intermediate-freuqncy signal by frequency mixer Mixer first, by bandpass filteringEnter A-D converter ADC after device BPF, be transformed into i/q signal by digital down converter DDC, is controlled by the first bandwidth singleFirst BWC selects the bandwidth and frequency of quasi- offseting signal, and bandwidth can pass through control.
Pre Filter is preselection filter module in attached drawing, and Detect Channel is detection receiving channel module,Receive Channel is receiver channel module, and Cancel Channel is to offset channel module.
The I/Q output signal of detection receiving channel module enters counteracting channel module, is transformed by Digital Up Convert DUCDigital intermediate frequency, then pass through digital delaying circuit DDL, the digital delaying circuit can finely regulating signal phase, be sent to countMode converter DAC, is transformed into analog signal, and low-pass filtered device generates and original signal size phase after filtering out high frequency clock signalDeng, the analog intermediate frequency signal of opposite in phase, transformed on radio frequency band by upper frequency mixer Mixer3, it is logical into receiverRoad sums with original reception signal, enters back into frequency mixer.At this point, the signal into frequency mixer will contain only small signal, and it is bigSignal has been offset because of opposite in phase.Reduce the linearity of frequency mixer below and amplifier circuit.In receiver channelDelay circuit DL be delayed to analog signal, with guarantee offseting signal generate time it is consistent with this channel.System designIn, the sample rate of ADC is improved as far as possible, otherwise computing relay is excessive, can make thrashing.
Receiving channel module and receiver channel module are detected in attached drawing 2, shares a local oscillation signal, and this design can be withRealize that the interference in IF passband bandwidth is eliminated, as shown in figure 3, it gives the realizations of two-way Digital Down Convert DDC circuitMethod.Its framework is almost the same, is mainly made of multiplier, FIR filter, half-band filter HB, digital oscillator NCO,There are two differences for the two, and the frequency of two digital oscillators is different, as can be seen that two frequency phase-difference Δ f, this Δ f in figureIt is exactly the difference on the frequency of strong and weak signals, feed back input after which is obtained by systematic survey.In addition sense channel needs a bandwidthControl circuit, the purpose is to control the bandwidth of offseting signal, by one group of filtering, therefore reconstitutable digital filter is constituted.
The system that attached drawing 2 and attached drawing 3 are constituted, can offset the signal in midband, at this time the frequency of high low signalRate interval is closer, is difficult to separate with filter in radio-frequency head.
The embodiment of the present invention one can also be used for the wider occasion of some broadband receivers and signal frequency interval, such as attached drawingShown in 4.Compared with attached drawing 2, sense channel has used independent local oscillator unit, rather than shares local oscillator with receiver channel, thisA system it is more adaptable, can not only offset the signal of proximal end, and the farther signal of frequency can be offset.Only hardwareSystem can improve, and structure can be complicated.At this point, the frequency difference of receiver channel and interference signal is arrived in setting by two local oscillator frequency differencesOn.
Generation for offseting signal, current high-speed DAC have begun maturation and provide commercialization, are directly by DACExportable broadband rf signal.The embodiment of the present invention two gives a kind of scheme that offseting signal is directly generated by DAC, such asShown in attached drawing 5, process of the program due to reducing up-conversion substantially reduces the complexity for offsetting channel.
Since of the invention is somebody's turn to do the system schema based on radio frequency cancellation mechanism, big signal can effectively reduce to the shadow of systemIt rings, by monitoring the actual power of signal of interest periphery frequency spectrum, generates letter equal with the signal power, opposite in phase in real timeNumber, it offsets and givees a signal in radio-frequency channel, thus to promote receiver system actual dynamic range, and have and automatically track,Automotive resistance is very suitable to the application of small-signal receiver.
Using the above-mentioned circuit structure for improving receiver dynamic range based on reverse phase cancellation mechanism of the invention, by penetratingThe method of frequency signal cancellation, in the case of realizing strong jamming, the small received validity of signal.Have the advantage that (1) passes through counteractingMechanism can effectively inhibit high reject signal present in channel, to realize measurement analysis of small signal etc., identical electricityLine structure substantially increases the linear dynamic range of system, passes through this method, at least improvement Dynamic Range 20dB, warpIt crosses after fine adjustment up to 30~35dB.(2) the method is especially suitable for the closely spaced signal processing of signal frequency, and before this,It handles extremely difficult for the interference signal in this band or even cannot achieve.(3) interval of offseting signal and bandwidth be allIt is program-controlled and automatically track, it is easy to use.(4) this programme has certain scalability, can increase sense channel quantity,Realized application existing for a high reject signal.
In this description, the present invention is described with reference to its specific embodiment.But it is clear that can still makeVarious modifications and alterations are without departing from the spirit and scope of the invention.Therefore, the description and the appended drawings should be considered as illustrativeAnd not restrictive.