CN104008409B - The optical link of antenna and reader is connected in passive RFID system - Google Patents
The optical link of antenna and reader is connected in passive RFID system Download PDFInfo
- Publication number
- CN104008409B CN104008409B CN201410182802.9A CN201410182802A CN104008409B CN 104008409 B CN104008409 B CN 104008409B CN 201410182802 A CN201410182802 A CN 201410182802A CN 104008409 B CN104008409 B CN 104008409B
- Authority
- CN
- China
- Prior art keywords
- signal
- module
- phase
- amplitude
- self
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Landscapes
- Mobile Radio Communication Systems (AREA)
- Noise Elimination (AREA)
Abstract
The present invention relates to the optical links that antenna and reader are connected in a kind of passive RFID system, due to using optical link structure, it is readily adapted for use in different environment wirings, and optical link loss very little in the case where long distance transmission, the features such as transmission suitable for Large Volume Data, the distribution that antenna can be improved improves the receiving sensitivity of system, is adapted to identify the application scenarios of big quantity electronic tag.It solves and identifies that the range of label is smaller present in existing passive RFID system, the not high problem of recognition accuracy.It can be widely used in that storehouse management in logistic storage, identification, communications and transportation, food medical treatment, the care of animal, gate inhibition be antitheft and the multiple fields such as industrial military affairs.
Description
Technical field
The present invention relates to antenna and reading are connected in passive radio frequency identification technique field more particularly to a kind of passive RFID system
Write the optical link of device.
Background technique
Radio Frequency Identification Technology (Radio Frequency Identification, RFID) is a kind of contactless automatic
Identification technology, the basic principle is that using radiofrequency signal and Space Coupling transmission characteristic automatic identification target object and obtaining related
Information realizes automatic identification.RFID technique has very extensive application prospect, and being increasingly valued by people it can answer
It is antitheft and industrial for the storehouse management in logistic storage, identification, communications and transportation, food medical treatment, the care of animal, gate inhibition
The multiple fields such as military affairs bring great convenience to people's life.
Passive radio frequency identification system is the mainstream of current RFID technique application, in hyperfrequency and microwave band, passive RFID
Technology is based primarily upon electromagnetic wave backscattering principle.Relative to active RFID system, the attainable identification of passive RFID system institute
The range of label is smaller, and the highest level that can reach currently on the market is 12m or so；And coping with the passive of intensive quantity
The recognition accuracy of electronic tag, the reader of passive RFID system also has great limitation.Cause the original of two above problem
Because as follows: first, passive electronic label itself does not provide energy, the electricity that the energy of labeling task is reflected back from reader
Magnetic wave；For reader, reader used in passive RFID system then use gimmick simultaneously, with the communication party of frequency
Formula.So the isolation of reader transmitting path and receiving path will affect total system for passive RFID system
Receiving sensitivity.In the prior art, the realization of passive RFID system transceiver insulation mainly uses circulator or directional coupler
(also referred to as " transceiver insulation module "), in the matched situation of all of the port, the isolation of " transceiver insulation module " in 20~30dB,
So that the power (i.e. most important " self-interference " signal power) that transmitting path leaks into receiving path is far longer than electronics mark
Reflected signal power is signed, this makes the receiving sensitivity of entire passive RFID system with regard at a fairly low, to make electronics mark
The reading/writing distance of label is shorter, the number of labels of identification is limited.Second, there are also other two parts to come for above-mentioned described self-interference signal
Source, a part are derived from the impedance mismatch of antenna end, when transmitting path emits modulated signal, have reflection standing wave and are formed
Interference signal enter in receiving channel；Another part is the modulated signal launched, by the Ambient around label
Afterwards, enter in receiving channel with tag reflection signal, both self-interference signals also can all influence the receiving sensitivity of system.The
Three, there are two types of the combinations of reader and antenna currently on the market, and one is antenna and reader is integrated, one
Change, another kind is to connect antenna by coaxial cable with reader, both combinations all limit passive RFID system
Reading/writing distance and tag recognition quantity.This is because the day of the distribution and distribution of reader and antenna integrated aft antenna
Line number amount is restricted, and has no idea to arrange antenna in extensive range；Antenna and reader pass through coaxial cable phase
Company will lead to the small-signal received from antenna end in significantly weak after the biggish coaxial cable of insertion loss, influence
The receiving sensitivity of rear end reader.
It to sum up states, the problem of existing passive RFID system is the attainable identification label of passive RFID system institute
Range is smaller；And when coping with the passive electronic label of intensive quantity, the recognition accuracy of the reader of passive RFID system
Also there is great limitation.
Summary of the invention
(1) technical problems to be solved
The technical problem to be solved in the present invention is to how solve identification label present in existing passive RFID system
Range is smaller, the not high problem of recognition accuracy.
(2) technical solution
In order to solve the above-mentioned technical problems, the present invention provides antenna and reader are connected in a kind of passive RFID system
Optical link, which is characterized in that receive uplink signal for emitting downlink signal including reader chip；First electric signal turns light
Signaling module is connect with reader chip, and for the signal received to be converted into optical signal, is inputted after optical fiber transmits
One optical signal turns signal module；First optical signal turns signal module, for the signal received to be converted into electric signal, and
Input multi-stage Low Noise Amplifier；Sequentially connected multi-stage Low Noise Amplifier and power amplifier turn for amplifying optical signal
The radiofrequency signal of signal module output, and amplified radiofrequency signal is sent to the input for being input to the first directional coupler
End；First directional coupler, for cooperating rear end antenna to separate uplink and downlink both links, the downlink of the first directional coupler
Signal output end is also the input terminal of uplink signal, this end and antenna connect, the input terminal of second adjustment circuit in uplink
Connect with the output end of the uplink signal of the first directional coupler；Since the isolation of the first orthotype coupler is limited, downlink
Signal has part energy when passing through directional coupler and leaks into uplink, generates self-interference signal；Antenna
Downlink signal is sent to passive electronic label in the form of an electromagnetic wave；Passive electronic label carries out the electromagnetic wave signal of downlink anti-
Modulation is penetrated, uplink signal is obtained；Antenna receives uplink signal, and by the first directional coupler, uplink signal and self-interference are believed
Number it is output to the first low-noise amplifier together；Then first low-noise amplifier is inputted for amplifying the signal received
Turn optical signal module to the second electric signal；Second electric signal turns optical signal module, for the electric signal received to be converted into light
Then signal transmits by optical fiber, is input to the second optical signal and turns signal module；Second optical signal turns signal module, uses
After the optical signal received is converted into electric signal, it is output to the second low-noise amplifier；Second low-noise amplifier, is used for
The signal received is amplified, is then input in the receiving port of reader chip；
Wherein reader chip, the first electric signal turn optical signal module, the second optical signal turns signal module, the second low noise
The proximal part of acoustic amplifier composition optical link；
First optical signal turns signal module, multi-stage Low Noise Amplifier, power amplifier, antenna end, the first orientation coupling
Clutch, the first low-noise amplifier, the second electric signal turn the distal portions of optical signal module composition optical link；
Wherein between the first directional coupler and the first low-noise amplifier or reader chip and the first electric signal
Turn between optical signal module, is provided with adjustment circuit at only one.
Preferably, adjustment circuit is provided between first directional coupler and the first low-noise amplifier；
The adjustment circuit includes that power splitter and self-interference eliminate circuit；
Wherein, it includes detection module, adjustment module, feedback module and combiner that self-interference, which eliminates circuit,；
First directional coupler, for cooperating antenna separation uplink and downlink, by a part of downlink signal
Signal is input to the input terminal of antenna, and a part is coupled to coupled end and exports the reference signal eliminated as distal end self-interference, also
Some signals leakiness is used as self-interference signal, and the uplink signal of receiving antenna output into uplink, and will be certainly
Interference signal and uplink signal are output in power splitter as new uplink signal；
Detection module includes amplitude detection module and phase detecting module, and adjustment module includes amplitude adjusting module and phase
Adjust module；
It adjusts module and adjusts the amplitude and phase of reference signal for the characteristic according to uplink signal；Wherein downlink signal
Couple the reference signal that a part of signal is eliminated as self-interference；
Uplink signal for receiving the uplink signal of the first directional coupler output, and is divided into three tunnels, all the way by power splitter
Significantly signal is input to one of input terminal of combiner, and in addition two-way small amplitude signal is separately input in detection module
Amplitude detection module and phase detecting module in；
Amplitude detection module and phase detecting module receive the two-way small amplitude signal of power splitter output, after tested
Output amplitude controls signal and phase control signal
Amplitude adjusting module and phase adjusting module, for receiving amplitude control signal and the phase control of detection module output
Signal processed carries out amplitude adjustment and phase tune to reference signal according to the amplitude control signal and phase control signal received
Whole, signal is eliminated in output, and to eliminate the relationship that the self-interference signal in signal and uplink signal is constant amplitude reverse phase；
Combiner, one of input terminal are used to receive the significantly signal all the way of power splitter output, another input terminal
For receiving the elimination signal of adjustment module output, output end is for exporting the signal that disappeared；
Feedback module is detected for extracting a part of signal that disappeared, detects the effect of elimination, and staining effect is arrived
Phase detecting module in detection module；
Wherein, the signal that disappeared is uplink signal after self-interference eliminates circuit, and self-interference signal is significantly disappeared
Signal after removing；
Eliminating signal is the reference signal of downlink signal coupling output according to the feature of the self-interference signal in uplink signal
Signal made of adjustment.
Preferably, the reader chip and the first electric signal turn to be provided with adjustment circuit between optical signal module, described
Adjustment circuit includes that the second directional coupler, power splitter and self-interference eliminate circuit；
Wherein, it includes detection module, adjustment module, feedback module and combiner that self-interference, which eliminates circuit,；
Second directional coupler, the downlink signal for exporting reader are coupled out part downlink signal as self-interference
The reference signal of elimination；
Detection module includes amplitude detection module and phase detecting module, and adjustment module includes amplitude adjusting module and phase
Adjust module；
It adjusts module and adjusts the amplitude and phase of reference signal for the characteristic according to uplink signal；
Power splitter is divided into three tunnels for receiving the uplink signal of the second low-noise amplifier output, and by uplink signal, and one
Significantly signal is input to one of input terminal of combiner on road, and in addition two-way small amplitude signal is separately input to detection module
In amplitude detection module and phase detecting module in；
Amplitude detection module and phase detecting module receive the two-way small amplitude signal of power splitter output, after tested
Output amplitude controls signal and phase control signal
Amplitude adjusting module and phase adjusting module, for receiving amplitude control signal and the phase control of detection module output
Signal processed carries out amplitude adjustment and phase tune to reference signal according to the amplitude control signal and phase control signal received
Whole, signal is eliminated in output, and to eliminate the relationship that the self-interference signal in signal and uplink signal is constant amplitude reverse phase；
Combiner, one of input terminal are used to receive the significantly signal all the way of power splitter output, another input terminal
For receiving the elimination signal of adjustment module output, output end is for exporting the signal that disappeared；
Feedback module is detected for extracting a part of signal that disappeared, detects the effect of elimination, and staining effect is arrived
Phase detecting module in detection module.
Preferably, the detection module further includes control centre, and the control centre is connected with the output end of detection module
It connects, self-interference is connected between control centre and amplitude detection module and eliminates enable signal, and the control centre is set to phase
Between position detection module and the connection of feedback module；
It further includes buffer that the self-interference, which eliminates circuit, and one input terminal of the buffer passes through enable signal and control
Center connection, another input terminal are connected with the output end of adjustment module, and the buffer is set to adjustment module and combining
Between the connection of device；
The self-interference eliminates enable signal, is the self-interference signal that control centre detects according to amplitude detection module
Amplitude judges whether the foundation for needing to eliminate self-interference signal；
The enable signal is control centre according to whether what the case where eliminating to self-interference signal issued makes
Energy signal, controls the output of buffer.
Preferably, the phase detecting module by bandpass filter, phase discriminator, the first analog-digital converter, micro-control unit,
First digital analog converter composition；
The amplitude detection module is by first detector, shaping circuit and the second analog-digital converter, micro-control unit, second
Digital analog converter composition；
Wherein phase detecting module is same with the micro-control unit in amplitude detection module；
The amplitude adjusting module is controllable gain amplifier, and the phase adjusting module is controllable phase shifter；
Wherein, bandpass filter is input in phase discriminator later for filtering out other frequency components；Phase discriminator is used for
The phase difference for detecting signal to be detected and reference signal is output in the first analog-digital converter in a manner of voltage signal；The
One analog-digital converter inputs micro-control unit after converting the signal to digital signal；Micro-control unit is used for the phase according to input
It detects signal and feedback signal carries out operation, phase adjustment signal is finely adjusted, and then export optimal phase adjustment signal；
First digital analog converter, the signal for exporting micro-control unit are converted to analog signal to control controllable phase shifter；
First detector, including envelope detector and comparator, when detection signal is input in envelope detector, output
Envelope signal, the envelope signal represent the amplitude size of uplink signal, if the range value is greater than preset threshold in comparator
Value, comparator will export self-interference and eliminate enable signal to micro-control unit, while micro-control unit exports enable signal, no
Then micro-control unit output signal is zero；Shaping circuit for receiving envelope signal, and is adjusted to adapt to the second modulus turn
The signal of parallel operation input range；Micro-control unit, for carrying out operation according to input range information and feedback signal, to amplitude tune
Entire signal is finely adjusted, and exports optimal amplitude adjusted signal, is converted into analog signal by the second digital analog converter to control
Controllable gain amplifier works；
Under the control of phase adjustment signal, reference signal phase shift obtains according to known phase difference for controllable phase shifter
To the elimination signal with self-interference signal reverse phase；
Controllable gain amplifier, according to known amplitude information, under the control of amplitude adjusted signal in adjustment circuit
Gain carries out amplification or decaying appropriate to reference signal, it is made to meet the relationship with self-interference signal constant amplitude；
The feedback module includes the second power splitter, second detector, third analog-digital converter；
Second power splitter is divided into two-way for the signal that will disappear, and high-power signal is output to RFID reader core all the way
In piece, another way low-power level signal is output in second detector；
Second detector for detecting signal detection amplitude size, and transmits a signal in third analog-digital converter；
Third analog-digital converter, converts a signal into digital signal, and output signal arrives microcontroller as feedback signal, feedback
Unit, the foundation as fine tuning.
(3) beneficial effect
The optical link that antenna and reader are connected in passive RFID system of the invention holds due to using optical link structure
It is readily adapted for different environment wirings, and optical link loss very little in the case where long distance transmission, suitable for Large Volume Data
The distribution of antenna can be improved in the features such as transmission, improves the receiving sensitivity of system, is adapted to identify big quantity electronics mark
The application scenarios of label.
Detailed description of the invention
In order to more clearly explain the embodiment of the invention or the technical proposal in the existing technology, to embodiment or will show below
There is attached drawing needed in technical description to be briefly described, it should be apparent that, the accompanying drawings in the following description is only this
Some embodiments of invention for those of ordinary skill in the art without creative efforts, can be with
It obtains other drawings based on these drawings.
Fig. 1: the structural representation of the optical link of antenna and reader is connected in a kind of passive RFID system provided by the invention
Figure；
Fig. 2: self-interference provided by the invention eliminates the structural schematic diagram of circuit；
Fig. 3: the optical link that antenna and reader are connected in the passive RFID system of circuit is distally eliminated with self-interference
Structural schematic diagram；
Fig. 4: the optical link that antenna and reader are connected in the passive RFID system of circuit is eliminated with self-interference in proximal end
Structural schematic diagram；
Fig. 5: numerically controlled self-interference provided by the invention eliminates the structural schematic diagram of circuit；
Fig. 6: it is distally eliminated with numerically controlled self-interference and connects antenna and reader in the passive RFID system of circuit
Optical link structural schematic diagram；
Fig. 7: proximal end is eliminated with numerically controlled self-interference connects antenna and reader in the passive RFID system of circuit
Optical link structural schematic diagram；
Fig. 8: the numerically controlled self-interference with specific structure provided by the invention eliminates the structural schematic diagram of circuit；
Fig. 9: distally connect in the passive RFID system of the self-interference elimination circuit with numerically controlled with specific structure
Connect the structural schematic diagram of the optical link of antenna and reader；
Figure 10: proximal end connects in the passive RFID system with the numerically controlled self-interference elimination circuit with specific structure
Connect the structural schematic diagram of the optical link of antenna and reader；
Specific embodiment
Embodiments of the present invention are described in further detail with reference to the accompanying drawings and examples.Following embodiment is used for
Illustrate the present invention, but cannot be used to limit the scope of the invention.
Embodiment 1, as shown in Figure 1, providing the optical link for connecting antenna and reader in a kind of passive RFID system, packet
Reader chip is included, for emitting downlink signal, receives uplink signal；First electric signal turns optical signal module and reader chip
Connection, for the signal received to be converted into optical signal, the first optical signal is inputted after optical fiber transmits and turns signal module；
First optical signal turns signal module, for the signal received to be converted into electric signal, and inputs multi-stage Low Noise Amplifier；
Sequentially connected multi-stage Low Noise Amplifier and power amplifier turn the radio frequency letter of signal module output for amplifying optical signal
Number, and amplified radiofrequency signal is sent to the input terminal for being input to the first directional coupler；First directional coupler, for matching
It closes rear end antenna and separates uplink and downlink both links, the downlink signal output end of the first directional coupler is also uplink signal
Input terminal, this end and antenna connect, and the uplink of the input terminal of second adjustment circuit and the first directional coupler is believed in uplink
Number output end connect；Since the isolation of the first orthotype coupler is limited, downlink signal by directional coupler when
Time has part energy and leaks into uplink, generates self-interference signal；Antenna by downlink signal in the form of an electromagnetic wave
It is sent to passive electronic label；Passive electronic label carries out reflection modulation to the electromagnetic wave signal of downlink, obtains uplink signal；Antenna
Uplink signal is received uplink signal and self-interference signal are output to the first low noise together and put by the first directional coupler
Big device；First low-noise amplifier is then input to the second electric signal and turns optical signal mould for amplifying the signal received
Block；Second electric signal turns optical signal module, for the electric signal received to be converted into optical signal, then transmits by optical fiber,
It is input to the second optical signal and turns signal module；Second optical signal turns signal module, for converting the optical signal received
After electric signal, it is output to the second low-noise amplifier；Second low-noise amplifier, for amplifying the signal received, so
It is input in the receiving port of reader chip afterwards；
Wherein reader chip, the first electric signal turn optical signal module, the second optical signal turns signal module, the second low noise
The proximal part of acoustic amplifier composition optical link；
First optical signal turns signal module, multi-stage Low Noise Amplifier, power amplifier, antenna end, the first orientation coupling
Clutch, the first low-noise amplifier, the second electric signal turn the distal portions of optical signal module composition optical link；
Wherein between the first directional coupler and the first low-noise amplifier or reader chip and the first electric signal
Turn between optical signal module, is provided with adjustment circuit at only one.
In the course of work, reader chip downlink signal is adjusted circuit integrated at meeting E/O module input range
Signal, the optical signal then converted are transferred to distal portions by optical fiber, first pass around O/E module and are converted into electric signal,
Then uplink signal finally reaches antenna end after the amplification of multi-stage Low Noise Amplifier (LNA) and power amplifier (PA)
Carry out electromagnetic radiation.Passive electronic label, which receives, carries out reflection modulation after electromagnetic wave signal, the uplink signal of reflection and from dry
It disturbs Signal averaging to enter in receiving channel, is adjusted after circuit does amplification or decaying appropriate and is input in LNA, LNA is appropriate
It is amplified into E/O module, is converted into optical signal and is transmitted on optical fiber, then again converted optical signal by O/E module
At electric signal, in the receiving port that is finally input to reader after LNA suitably amplifies.Due to optical fiber link and coaxial cable
It compares: being readily adapted for use in different environment wirings, link load very little in the case where long distance transmission is suitable for Large Volume Data
Transmission the features such as, the distribution of antenna can be improved, improve the receiving sensitivity of system, be adapted to identify big quantity electronics
The application scenarios of label.
Embodiment 2: on the basis of embodiment 1, present embodiments provide in a kind of passive RFID system connection antenna and
The optical link of reader is equipped with self-interference in the link and eliminates circuit, as shown in Figure 2；The self-interference, which eliminates circuit, can guarantee system
The receiving sensitivity of system.
Self-interference shown in Fig. 2 is eliminated into circuit and is set to the optical link of connection antenna and reader in passive RFID system
Distally, as shown in Figure 3.Specifically, adjustment circuit is provided between first directional coupler and the first low-noise amplifier；
The adjustment circuit includes that power splitter and self-interference eliminate circuit；The optical link applications are few in distal end distribution antenna quantity, passive
Range locating for electronic tag is more complex, and downlink signal reveals serious situation.
The self-interference for being set to distal end is eliminated circuit and is made of three parts: detection module, adjustment module and feedback module.
Since self-interference signal mainly in the first directional coupler reveal by downlink signal, so utilizing the first directional coupler
The reference signal of the downlink of the output of coupled end come simulate through leakage and extraneous reflection after elimination signal, so reference signal
It is input in adjustment module.Uplink signal flows to power splitter by the first directional coupler, and uplink signal is divided into three by power splitter
Road, significantly signal is input to one of input of combiner all the way, and in addition two-way small amplitude signal is separately input to detect
In amplitude detection module and phase detecting module in module.Since in uplink signal, self-interference signal is far longer than reflection
Label signal back, so detection module is exactly the amplitude and phase in detection self-interference signal.Width is exported after tested
Degree control signal and phase control signal.This two path control signal is separately input to amplitude adjusting circuit and phase-adjusting circuit
In, amplitude adjustment and phase adjustment are carried out to reference signal, so that in the elimination signal and uplink signal of adjustment module output
Self-interference signal is the relationship of constant amplitude reverse phase.The elimination signal of adjustment module output is input to the another way input terminal of combiner
In, the signal of combiner output should be the signal that disappeared carried out after self-interference elimination.Due to the adjustment essence of phase adjusting module
Spend it is limited, generally can only by reference signal and eliminate signal between phase difference accomplish 170 °~190 °, so self-interference eliminate
Feedback module in circuit can extract a part signal that disappeared and be detected, and detect the effect of elimination, and by staining effect to examining
The phase detecting module in module is surveyed, phase detecting module will do it corresponding adjustment, to improve self-interference signal next time
The precision of elimination.
Self-interference shown in Fig. 2 is eliminated into circuit and is set to the optical link of connection antenna and reader in passive RFID system
Proximal end realizes the elimination of self-interference by the self-adjusting circuit of proximal end, as shown in Figure 4.Specifically, the reader chip and
One electric signal turns to be provided with adjustment circuit between optical signal module, and the adjustment circuit includes the second directional coupler, power splitter
Circuit is eliminated with self-interference；Proximal end is suitable for remote antenna module with the optical link passive RFID system that self-interference eliminates function
Smaller, distribution is close and wide, and the leakage of the first directional coupler is not very seriously that optical link, which generates, to be interfered in biggish situation.
Specific circuit implementing method is identical with distal end.Proximal end self-interference is eliminated circuit and is made of three parts: detection mould
Block, adjustment module and feedback module.Since self-interference signal mainly in the first directional coupler reveal by downlink signal,
But self-interference eliminate circuit be located at proximal end, so using the reference signal of the downlink of the output of the second directional coupler coupled end come
The self-interference signal (signal of formation is known as " eliminating signal ") after revealing and the external world is reflected is simulated, so reference signal is defeated
Enter into adjustment module.Uplink signal flows to power splitter by LNA2, and uplink signal is divided into three tunnels by power splitter, all the way significantly
Signal is input to one of input of combiner, and in addition two-way small amplitude signal is separately input to the inspection of the amplitude in detection module
It surveys in module and phase detecting module.Since in uplink signal, self-interference signal is far longer than reflected label signal,
So detection module is exactly the amplitude and phase in detection self-interference signal.Output amplitude control signal and phase after tested
Control signal.This two path control signal is separately input in amplitude adjusting circuit and phase-adjusting circuit, is carried out to reference signal
Amplitude adjustment and phase adjustment, so that the self-interference signal in the elimination signal and uplink signal of adjustment module output is that constant amplitude is anti-
The relationship of phase.The elimination signal of adjustment module output is input in the another way input terminal of combiner, the signal of combiner output
It should be the signal that disappeared carried out after self-interference elimination.Since the Adjustment precision of phase adjusting module is limited, can only will generally join
The phase difference examining signal and eliminating between signal accomplishes 170 °~190 °, so the feedback module that self-interference is eliminated in circuit can mention
It takes a part of signal that disappeared to be detected, detects the effect of elimination, and the phase-detection mould by staining effect into detection module
Block, phase detecting module will do it corresponding adjustment, to improve the precision that self-interference signal is eliminated next time.
Embodiment 3: it in embodiment 1 and on the basis of embodiment 2, present embodiments provides and connects in a kind of passive RFID system
The optical link of antenna and reader is connect, numerically controlled self-interference is equipped in the link and eliminates circuit, as shown in Figure 5.
Eliminate circuit equipped with numerically controlled self-interference and be divided into four parts: detection module, adjustment module, feedback module and
Buffer.It include: amplitude detection module, phase detecting module, control centre in detection module.Adjusting module includes: amplitude tune
Mould preparation block, phase adjusting module.Its present principles is: uplink signal is input at power splitter, and uplink signal is divided into three by power splitter
Road, significantly signal is input to one of input of combiner all the way, and in addition two-way small amplitude signal is separately input to detect
In amplitude detection module and phase detecting module in module.Since in uplink signal, self-interference signal is far longer than reflection
Label signal back, so detection module is exactly the amplitude and phase in detection self-interference signal.Amplitude is examined after testing
It surveys module output amplitude control signal and self-interference eliminates enable signal (SJCEN), phase detecting module output phase control letter
Number.Amplitude control signal and phase control signal are separately input in amplitude adjusting circuit and phase-adjusting circuit, are believed reference
Number amplitude adjustment and phase adjustment are carried out, so that the self-interference signal in the elimination signal and uplink signal of adjustment module output is
The relationship of constant amplitude reverse phase.The elimination signal of adjustment module output is input in the another way input terminal of combiner, combiner output
Signal should be carry out self-interference elimination after tag reflection signal (referred to as " disappeared signal ").In addition signal is controlled all the way
SJCEN is input to control centre, and whether its effect is to detect the interference effect of self-interference signal to reach and need the case where eliminating,
If self-interference signal is not necessarily to eliminate, SJCEN is notified that control centre, and then it is enabled to generate output for control centre
Signal (EN) controls buffer, and making its output is zero, and the signal exported in such combiner is exactly not carry out self-interference elimination
Uplink signal；If self-interference signal reaches the standard for needing to eliminate, SJCEN is notified that control centre, at this moment in control
The heart can tell buffer, will eliminate signal and be input in combiner, carry out self-interference and eliminate work.Such structure can help
Self-interference cancellation module selects different working methods according to different external environments, improves system effectiveness, saves energy.Due to
The Adjustment precision of phase adjusting module is limited, generally can only by reference signal and eliminate signal between phase difference accomplish 170 °~
190 °, so the feedback module that self-interference eliminates in circuit can extract a part of signal that disappeared and be detected, detect the effect of elimination
Fruit, and the control centre by staining effect into detection module, control centre carry out operation according to obtained feedback signal, obtain
Corresponding phase compensation signal is input to phase detecting module, and phase detecting module will do it corresponding adjustment, to improve down
The precision that self-interference signal is eliminated.
According to different application scenarios, numerically controlled self-interference, which eliminates circuit, can be used different positions in optical link
In setting.
The numerically controlled self-interference elimination circuit shown in fig. 5 that is equipped with is set to connection antenna and reading in passive RFID system
The distal end of the optical link of device is write, as shown in Figure 6.Specifically, between first directional coupler and the first low-noise amplifier
It is provided with adjustment circuit；The adjustment circuit includes that power splitter and self-interference eliminate circuit；The optical link applications are distributed in distal end
Antenna amount is few, and range locating for passive electronic label is more complex, and downlink signal reveals serious situation.
Distal end is made of with numerically controlled self-interference elimination circuit self-interference elimination circuit three parts: detection mould
Block, adjustment module and feedback module.Since self-interference signal mainly in the first directional coupler reveal by downlink signal,
So the reference signal of the downlink using the output of the first directional coupler coupled end, to simulate after revealing and the external world is reflected
Self-interference signal (signal of formation is known as " eliminate signal "), so reference signal is input in adjustment module.Uplink signal
Power splitter is flowed to by the first directional coupler, uplink signal is divided into three tunnels by power splitter, and significantly signal is input to conjunction all the way
One of input of road device, in addition two-way small amplitude signal is separately input to amplitude detection module and phase in detection module
In detection module.Since in uplink signal, self-interference signal is far longer than reflected label signal, so detection module
It is exactly the amplitude and phase in detection self-interference signal.Amplitude detection module output amplitude controls signal and does certainly after tested
It disturbs and eliminates enable signal (SJCEN), phase detecting module output phase controls signal.Amplitude control signal and phase control signal
It is separately input in amplitude adjusting circuit and phase-adjusting circuit, amplitude adjustment and phase adjustment is carried out to reference signal, so that
Self-interference signal in the elimination signal and uplink signal of adjustment module output is the relationship of constant amplitude reverse phase.Adjust module output
It eliminates signal to be input in the another way input terminal of combiner, the signal of combiner output should be after carrying out self-interference elimination
Disappeared signal.In addition control signal SJCEN is input to control centre all the way, its effect is the interference shadow for detecting self-interference signal
It rings whether to reach and needs the case where eliminating, if self-interference signal is not necessarily to eliminate, SJCEN is notified that control centre,
Then control centre can generate output enable signal (EN) control buffer, and making its output is zero, is exported in such combiner
Signal is exactly the uplink signal for not carrying out self-interference elimination；If self-interference signal reaches the standard for needing to eliminate, SJCEN
It is notified that control centre, at this moment control centre can tell buffer, will eliminate signal and be input in combiner, carry out self-interference and disappear
Except work.Such structure can help self-interference cancellation module to select different working methods according to different external environments,
System effectiveness is improved, energy is saved.It, generally can only be by reference signal and elimination since the Adjustment precision of phase adjusting module is limited
Phase difference between signal accomplishes 170 °~190 °, so the feedback module that self-interference eliminates in circuit can extract a part and disappear
Signal is detected, and detects the effect of elimination, and the control centre by staining effect into detection module, control centre according to
The feedback signal arrived carries out operation, obtains corresponding phase compensation signal and is input to phase detecting module, phase detecting module meeting
It is adjusted correspondingly, to improve the precision that self-interference signal is eliminated next time.
The numerically controlled self-interference elimination circuit shown in fig. 5 that is equipped with is set to connection antenna and reading in passive RFID system
The distal end of the optical link of device is write, as shown in Figure 7.Specifically, the reader chip and the first electric signal turn optical signal module it
Between be provided with adjustment circuit, the adjustment circuit includes that the second directional coupler, power splitter and self-interference eliminate circuit；It is suitable for
Remote antenna module is smaller, and distribution is close and wide, and the leakage of the first directional coupler is not that very seriously, it is biggish that optical link generates interference
In the case of.
Specific circuit implementing method is identical with distal end.Circuit is eliminated by three with numerically controlled self-interference in proximal end
Part forms: detection module, adjustment module and feedback module.Since self-interference signal is mainly from the first directional coupler
Middle downlink signal leakage, but self-interference eliminates circuit and is located at proximal end, so utilizing the output of the second directional coupler coupled end
The reference signal of downlink, to simulate the self-interference signal after revealing and the external world is reflected, (signal of formation is known as " eliminating letter
Number "), so reference signal is input in adjustment module.Uplink signal flows to power splitter by LNA2, and power splitter is by uplink signal
It is divided into three tunnels, significantly signal is input to one of input of combiner all the way, and in addition two-way small amplitude signal inputs respectively
In amplitude detection module and phase detecting module into detection module.Since in uplink signal, self-interference signal is much big
In reflected label signal, so detection module is exactly the amplitude and phase in detection self-interference signal.After tested
Amplitude detection module output amplitude controls signal and self-interference eliminates enable signal (SJCEN), phase detecting module output phase
Control signal.Amplitude control signal and phase control signal are separately input in amplitude adjusting circuit and phase-adjusting circuit, right
Reference signal carries out amplitude adjustment and phase adjustment, so that the self-interference of adjustment module output eliminated in signal and uplink signal
Signal is the relationship of constant amplitude reverse phase.The elimination signal of adjustment module output is input in the another way input terminal of combiner, is combined
The signal of device output should be the signal that disappeared carried out after self-interference elimination.In addition control signal SJCEN is input to control all the way
Center, whether its effect is to detect the interference effect of self-interference signal to reach and need the case where eliminating, if self-interference signal
It is not necessary to eliminate, then SJCEN is notified that control centre, then it is slow to generate output enable signal (EN) control for control centre
Device is rushed, making its output is zero, and the signal exported in such combiner is exactly the uplink signal for not carrying out self-interference elimination；If from
Interference signal reaches the standard for needing to eliminate, then SJCEN is notified that control centre, at this moment control centre can tell buffer,
Signal will be eliminated to be input in combiner, self-interference is carried out and eliminate work.Such structure can help self-interference cancellation module
Different working methods is selected according to different external environments, improves system effectiveness, saves energy.Due to phase adjusting module
Adjustment precision is limited, generally the phase difference between reference signal and elimination signal can only be accomplished 170 °~190 °, so from dry
It disturbs the feedback module eliminated in circuit and can extract a part signal that disappeared and detected, detect the effect of elimination, and effect is anti-
The control centre being fed in detection module, control centre carry out operation according to obtained feedback signal, obtain corresponding phase and mend
It repays signal and is input to phase detecting module, phase detecting module will do it corresponding adjustment, to improve self-interference letter next time
Number eliminate precision.
Embodiment 4: on the basis of embodiment 1, embodiment 2 and embodiment 3, a kind of passive RFID is present embodiments provided
The optical link of antenna and reader is connected in system, and the numerically controlled self-interference with specific structure is equipped in the link and is eliminated
Circuit, as shown in Figure 8；
Self-interference shown in Fig. 8 equipped with numerically controlled with specific structure is eliminated into circuit and is set to passive RFID system
The distal end of the optical link of middle connection antenna and reader, as shown in Figure 9.Specifically, first directional coupler and first low
Adjustment circuit is provided between noise amplifier；The adjustment circuit includes that power splitter and self-interference eliminate circuit；
RFID reader chip exports modulated downlink signal from transmission channel, is input in the E/O module of downlink,
Downlink signal is transferred in O/E module along optical link and is converted to electric signal, after multistage LNA and PA are amplified to appropriate power
It is input to antenna end, is oriented radiation.Passive electronic label carries out reflection modulation after receiving downlink signal, reflects signal
Along uplink, the self-interference for first carrying out distal end is eliminated.The numerically controlled adaptivity self-interference cancellation module of distal end
The course of work is: uplink signal initially enters power splitter, and uplink signal is divided into three tunnels by power splitter, and high-power signal inputs all the way
To the one of input terminal of combiner, in addition two-way low-power level signal is input in detection module.
Adjustment module is made of controllable phase shifter and controllable gain amplifier (AGC).
Detection module is made of amplitude detection module, phase detecting module, digital control center.
The phase detecting module is by bandpass filter (BPF), phase discriminator, the first analog-digital converter (AD1), microcontroller list
First (MCU), the first digital analog converter (DA1) composition；In order to preferably carry out phase-detection, enter BPF to phase detection signal
Other frequency components are filtered out, are input in phase discriminator later.Phase discriminator detects the phase of signal to be detected and reference signal
Difference is exported in a manner of voltage signal, is converted into digital signal by AD1 and is entered that MCU is to be processed, and MCU is according to the phase of input
It detects signal and feedback signal carries out operation (inquiring arithmetic), phase adjustment signal is finely adjusted, and then export optimal phase
Position adjustment signal is converted to analog signal by DA1 to control controllable phase shifter, and controllable phase shifter will according to known phase difference
Reference signal phase shift obtains the elimination signal with self-interference signal reverse phase.
The amplitude detection module is by including first detector, shaping circuit and the second analog-digital converter (AD2), MCU, the
Two digital analog converter DA2 composition.Signal to be detected first, which is input in the wave detector including comparator, exports envelope signal, the packet
Network signal represents the amplitude size of uplink signal, if the range value is greater than preset threshold value in comparator, comparator will
It exports self-interference and eliminates enable signal (ENSJC) into MCU, at this moment proximal end self-interference eliminates circuit and just starts to work, while MCU
Also can output buffer enable (EN) signal, the input signal of another input terminal of combiner is not zero at this time；If amplitude
Value is less than preset threshold value in comparator, then comparator can be into MCU, at this moment the self-interference of proximal end eliminates circuit stopping work
Make, at the same MCU also can output buffer enable (EN) signal, the input signal of another input terminal of combiner is zero at this time.
Then envelope signal enters shaping circuit, in order to adapt to the input range of AD2, carries out signal shaping, and AD2 is by amplitude detection signal
It is input in MCU, MCU carries out operation (inquiring arithmetic) according to input range information and feedback signal, exports optimal amplitude tune
Entire signal is converted into analog signal by DA2 to control AGC work, and AGC is according to known amplitude information, in adjustment circuit
Gain carries out amplification or decaying appropriate to reference signal, meets the relationship with self-interference signal constant amplitude.
Downlink signal is input in AGC as the oriented coupler coupled end of reference signal, have passed through amplitude adjustment and phase
The reference signal of position adjustment is input to the other end of combiner as signal is eliminated, due to eliminate in signal and uplink signal certainly
Interference signal reverse phase, the two are cancelled out each other, and influence of the self-interference signal to tag reflection signal is reduced.Feedback module includes the
Two power splitters, second detector, third analog-digital converter AD3.Second power splitter will eliminate signal and be divided into two-way, all the way big function
Rate signal is output in RFID reader chip, and another way low-power level signal is output in second detector, detects amplitude size
(effect namely eliminated) is converted to feedback signal by AD3, and feedback arrives MCU, the foundation as fine tuning.Uplink is believed later
Number carrying out appropriate amplify by optical link and LNA2 is output to the receiving end of RFID reader chip.
Self-interference shown in Fig. 8 equipped with numerically controlled with specific structure is eliminated into circuit and is set to passive RFID system
The proximal end of the optical link of middle connection antenna and reader, as shown in Figure 10, RFID reader chip exports modulated from transmission channel
Downlink signal, be input in the E/O module of downlink, downlink signal is transferred in O/E module along optical link and is converted to
Electric signal is input to antenna end after multistage LNA and PA are amplified to appropriate power, is oriented radiation.Passive electronic label
It receives downlink signal and carries out reflection modulation later, reflect signal along uplink, uplink signal first passes through LNA1 and fitted
When being enlarged into the signal for being suitble to transmit in optical link, LNA2 progress amplification appropriate is then transferred to by optical link and is output to closely
Self-interference is held to eliminate in circuit, the receiving end that will finally eliminate signal and be input to RFID reader chip.The number control of proximal end
The course of work of the adaptivity self-interference cancellation module of system is: uplink signal initially enters power splitter, and power splitter believes uplink
Number it is divided into three tunnels, high-power signal is input to the one of input terminal of combiner all the way, and in addition two-way low-power level signal is input to
In detection module.
Adjustment module is made of controllable phase shifter and AGC.
Detection module is made of amplitude detection module, phase detecting module, digital control center.
The phase detecting module is made of BPF, phase discriminator, AD1, micro-control unit, DA1；In order to preferably carry out phase
Position detection, enters BPF to phase detection signal and filters out other frequency components, be input in phase discriminator later.Phase discriminator detection
The phase difference of signal to be detected and reference signal out, is exported in a manner of voltage signal, is converted into digital signal by AD1 and is entered
MCU is to be processed, and MCU carries out operation (inquiring arithmetic) according to the phase detection signal and feedback signal of input, believes phase adjustment
It number is finely adjusted, and then exports optimal phase adjustment signal, analog signal is converted to by DA1 to control controllable phase shifter,
Controllable phase shifter, by reference signal phase shift, obtains the elimination signal with self-interference signal reverse phase according to known phase difference.
The amplitude detection module by first detector, shaping circuit and the second analog-digital converter AD2, micro-control unit,
Second digital analog converter DA2 composition.Signal to be detected first, which is input in the wave detector including comparator, exports envelope signal, should
Envelope signal represents the amplitude size of uplink signal, if the range value is greater than preset threshold value in comparator, comparator is just
Self-interference can be exported and eliminate enable signal (ENSJC) into MCU, at this moment proximal end self-interference eliminates circuit and just starts to work, simultaneously
MCU also can output buffer enable (EN) signal, the input signal of another input terminal of combiner is not zero at this time；Such as fruit bat
Angle value is less than preset threshold value in comparator, then comparator can be into MCU, at this moment the self-interference of proximal end eliminates circuit stopping work
Make, at the same MCU also can output buffer enable (EN) signal, the input signal of another input terminal of combiner is zero at this time.
Then envelope signal enters shaping circuit, in order to adapt to the input range of AD2, carries out signal shaping, and AD2 is by amplitude detection signal
It is input in MCU, MCU carries out operation (inquiring arithmetic) according to input range information and feedback signal, exports optimal amplitude tune
Entire signal is converted into analog signal by DA2 to control AGC work, and AGC is according to known amplitude information, in adjustment circuit
Gain carries out amplification appropriate (or decaying) to reference signal, meets the relationship with self-interference signal constant amplitude.
Downlink signal is input in AGC as reference signal through the second directional coupler coupled end, have passed through amplitude adjustment
With the reference signal of phase adjustment as the other end eliminated signal and be input to combiner, due to eliminating in signal and uplink signal
Self-interference signal reverse phase, the two cancels out each other, and reduces influence of the self-interference signal to tag reflection signal.
Feedback module includes the second power splitter, second detector, third analog-digital converter AD3.Second power splitter will disappear
Except signal is divided into two-way, high-power signal is output in RFID reader chip all the way, and another way low-power level signal is output to
It in two wave detectors, detects amplitude size (effect namely eliminated), is converted to feedback signal by AD3, feedback arrives MCU, makees
For the foundation of fine tuning.
The above embodiments are only used to illustrate the present invention, rather than limitation of the present invention.Although embodiment to the present invention into
Explanation is gone, it will be understood by those of skill in the art that carrying out various combinations, modification or equivalent to technical solution of the present invention
Replacement, without departure from the spirit and scope of technical solution of the present invention, is intended to be within the scope of the claims of the invention.
Claims (5)
1. connecting the optical link of antenna and reader in a kind of passive RFID system, which is characterized in that including reader chip, use
In transmitting downlink signal, uplink signal is received；First electric signal turns optical signal module and connect with reader chip, for that will receive
To signal be converted into optical signal, the first optical signal is inputted after optical fiber transmits and turns signal module；First optical signal turns electricity
Signaling module for the signal received to be converted into electric signal, and inputs multi-stage Low Noise Amplifier；Sequentially connected multistage
Low-noise amplifier and power amplifier turn the radiofrequency signal of signal module output for amplifying optical signal, and will be after amplification
Radiofrequency signal be sent to the input terminal for being input to the first directional coupler；First directional coupler, for cooperating rear end antenna point
From uplink and downlink both links, the downlink signal output end of the first directional coupler is also the input terminal of uplink signal, this end
Connect with antenna, the output end phase of the uplink signal of the input terminal of second adjustment circuit and the first directional coupler in uplink
It connects；Since the isolation of the first orthotype coupler is limited, downlink signal understands some when passing through directional coupler
Energy leakage generates self-interference signal into uplink；Downlink signal is sent to passive electronic by antenna in the form of an electromagnetic wave
Label；Passive electronic label carries out reflection modulation to the electromagnetic wave signal of downlink, obtains uplink signal；Antenna receives uplink letter
Number, by the first directional coupler, uplink signal and self-interference signal are output to the first low-noise amplifier together；First is low
Noise amplifier is then input to the second electric signal and turns optical signal module for amplifying the signal received；Second electric signal
Turn optical signal module, for the electric signal received to be converted into optical signal, then transmitted by optical fiber, is input to the second light letter
Number turn signal module；Second optical signal turns signal module, after the optical signal received is converted into electric signal, output
To the second low-noise amplifier；Second low-noise amplifier is then input to reader core for amplifying the signal received
In the receiving port of piece；
Wherein reader chip, the first electric signal turn optical signal module, the second optical signal turns signal module, the second low noise is put
The proximal part of big device composition optical link；
First optical signal turn signal module, multi-stage Low Noise Amplifier, power amplifier, antenna end, the first directional coupler,
First low-noise amplifier, the second electric signal turn the distal portions of optical signal module composition optical link；
Wherein between the first directional coupler and the first low-noise amplifier or reader chip and the first electric signal turn light
Between signaling module, adjustment circuit is provided at only one.
2. connecting the optical link of antenna and reader in passive RFID system according to claim 1, which is characterized in that institute
It states and is provided with adjustment circuit between the first directional coupler and the first low-noise amplifier；
The adjustment circuit includes that power splitter and self-interference eliminate circuit；
Wherein, it includes detection module, adjustment module, feedback module and combiner that self-interference, which eliminates circuit,；
First directional coupler, for cooperating antenna separation uplink and downlink, by a part of signal of downlink signal
It is input to the input terminal of antenna, a part is coupled to coupled end and exports the reference signal eliminated as distal end self-interference, and there are also one
Part signal leaks into uplink as self-interference signal, and the uplink signal of receiving antenna output, and by self-interference
Signal and uplink signal are output in power splitter as new uplink signal；
Detection module includes amplitude detection module and phase detecting module, and adjustment module includes amplitude adjusting module and phase adjustment
Module；
It adjusts module and adjusts the amplitude and phase of reference signal for the characteristic according to uplink signal；Wherein downlink signal couples
The reference signal that a part of signal is eliminated as self-interference；
Uplink signal for receiving the uplink signal of the first directional coupler output, and is divided into three tunnels, all the way substantially by power splitter
Degree signal is input to one of input terminal of combiner, and in addition two-way small amplitude signal is separately input to the width in detection module
It spends in detection module and phase detecting module；
Amplitude detection module and phase detecting module receive the two-way small amplitude signal of power splitter output, export after tested
Amplitude control signal and phase control signal
Amplitude adjusting module and phase adjusting module, for receiving the amplitude control signal and phase controlling letter of detection module output
Number, according to the amplitude control signal and phase control signal received, amplitude adjustment and phase adjustment are carried out to reference signal, it is defeated
Signal is eliminated out, and to eliminate the relationship that the self-interference signal in signal and uplink signal is constant amplitude reverse phase；
Combiner, one of input terminal be used for receive power splitter output significantly signal, another input terminal are used for all the way
The elimination signal of adjustment module output is received, output end is for exporting the signal that disappeared；
Feedback module is detected for extracting a part of signal that disappeared, and will test result and feed back the phase into detection module
Position detection module；
Wherein, the signal that disappeared is uplink signal after self-interference eliminates circuit, and self-interference signal is carried out after significantly eliminating
Signal；
Eliminating signal is the reference signal of downlink signal coupling output according to the Character adjustment of the self-interference signal in uplink signal
Made of signal.
3. connecting the optical link of antenna and reader in passive RFID system according to claim 1, which is characterized in that institute
It states reader chip and the first electric signal turns to be provided with adjustment circuit between optical signal module, the adjustment circuit includes second fixed
Circuit is eliminated to coupler, power splitter and self-interference；
Wherein, it includes detection module, adjustment module, feedback module and combiner that self-interference, which eliminates circuit,；
Second directional coupler, the downlink signal for exporting reader are coupled out part downlink signal and eliminate as self-interference
Reference signal；
Detection module includes amplitude detection module and phase detecting module, and adjustment module includes amplitude adjusting module and phase adjustment
Module；
It adjusts module and adjusts the amplitude and phase of reference signal for the characteristic according to uplink signal；
Uplink signal for receiving the uplink signal of the second low-noise amplifier output, and is divided into three tunnels, all the way greatly by power splitter
Range signal is input to one of input terminal of combiner, and in addition two-way small amplitude signal is separately input in detection module
In amplitude detection module and phase detecting module；
Amplitude detection module and phase detecting module receive the two-way small amplitude signal of power splitter output, export after tested
Amplitude control signal and phase control signal
Amplitude adjusting module and phase adjusting module, for receiving the amplitude control signal and phase controlling letter of detection module output
Number, according to the amplitude control signal and phase control signal received, amplitude adjustment and phase adjustment are carried out to reference signal, it is defeated
Signal is eliminated out, and to eliminate the relationship that the self-interference signal in signal and uplink signal is constant amplitude reverse phase；
Combiner, one of input terminal be used for receive power splitter output significantly signal, another input terminal are used for all the way
The elimination signal of adjustment module output is received, output end is for exporting the signal that disappeared；
Feedback module is detected for extracting a part of signal that disappeared, and will test result and feed back the phase into detection module
Position detection module.
4. connecting the optical link of antenna and reader in passive RFID system according to claim 2 or 3, feature exists
In the detection module further includes control centre, and the control centre carries out operation according to obtained feedback signal, is obtained corresponding
Phase compensation signal be input to phase detecting module, be connected between control centre and amplitude detection module self-interference elimination make
Energy signal, and the control centre is set between phase detecting module and the connection of feedback module；
It further includes buffer that the self-interference, which eliminates circuit, and one input terminal of the buffer passes through enable signal and control centre
Connection, another input terminal are connected with the output end of adjustment module, and the buffer, which is set to, adjusts module and combiner
Between connection；
The self-interference eliminates enable signal, is the width for the self-interference signal that control centre detects according to amplitude detection module
Degree, judges whether the foundation for needing to eliminate self-interference signal；
The enable signal is control centre according to whether the enabled letter that the case where eliminating to self-interference signal issues
Number, control the output of buffer.
5. connecting the optical link of antenna and reader in passive RFID system according to claim 2 or 3, feature exists
In the phase detecting module is by bandpass filter, phase discriminator, the first analog-digital converter, micro-control unit, the first digital-to-analogue conversion
Device composition；
The amplitude detection module is by first detector, shaping circuit and the second analog-digital converter, micro-control unit, the second digital-to-analogue
Converter composition；
Wherein phase detecting module is same with the micro-control unit in amplitude detection module；
The amplitude adjusting module is controllable gain amplifier, and the phase adjusting module is controllable phase shifter；
Wherein, bandpass filter is input in phase discriminator later for filtering out other frequency components；Phase discriminator, for detecting
The phase difference of signal to be detected and reference signal out is output in the first analog-digital converter in a manner of voltage signal；First mould
Number converter inputs micro-control unit after converting the signal to digital signal；Micro-control unit is used for the phase-detection according to input
Signal and feedback signal carry out operation, are finely adjusted to phase adjustment signal, and then export optimal phase adjustment signal；First
Digital analog converter, the signal for exporting micro-control unit are converted to analog signal to control controllable phase shifter；
First detector, including envelope detector and comparator export envelope when detection signal is input in envelope detector
Signal, the envelope signal represent the amplitude size of uplink signal, if the range value is greater than preset threshold value in comparator, than
Self-interference will be exported compared with device and eliminates enable signal to micro-control unit, while micro-control unit exports enable signal, it is otherwise micro-
Control unit output signal is zero；Shaping circuit for receiving envelope signal, and is adjusted to adapt to the second analog-digital converter
The signal of input range；Micro-control unit adjusts amplitude and believes for carrying out operation according to input range information and feedback signal
It number is finely adjusted, exports optimal amplitude adjusted signal, it is controllable to control to be converted into analog signal by the second digital analog converter
Gain amplifier works；
Controllable phase shifter, according to known phase difference, under the control of phase adjustment signal, by reference signal phase shift, obtain with
The elimination signal of self-interference signal reverse phase；
Controllable gain amplifier, according to known amplitude information, gain under the control of amplitude adjusted signal in adjustment circuit,
Amplification or decaying appropriate are carried out to reference signal, it is made to meet the relationship with self-interference signal constant amplitude；
The feedback module includes the second power splitter, second detector, third analog-digital converter；
Second power splitter is divided into two-way for the signal that will disappear, and high-power signal is output to RFID reader chip all the way
In, another way low-power level signal is output in second detector；
Second detector for detecting signal detection amplitude size, and transmits a signal in third analog-digital converter；
Third analog-digital converter, converts a signal into digital signal, and output signal arrives microcontroller list as feedback signal, feedback
Member, the foundation as fine tuning.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410182802.9A CN104008409B (en) | 2014-04-30 | 2014-04-30 | The optical link of antenna and reader is connected in passive RFID system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410182802.9A CN104008409B (en) | 2014-04-30 | 2014-04-30 | The optical link of antenna and reader is connected in passive RFID system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN104008409A CN104008409A (en) | 2014-08-27 |
| CN104008409B true CN104008409B (en) | 2019-04-02 |
Family
ID=51369057
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201410182802.9A Active CN104008409B (en) | 2014-04-30 | 2014-04-30 | The optical link of antenna and reader is connected in passive RFID system |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN104008409B (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104361475A (en) * | 2014-10-22 | 2015-02-18 | 江苏永鼎通信有限公司 | Warehouse management system adopting optical fiber distribution systems, in-warehouse method and ex-warehouse method |
| CN104467970A (en) * | 2014-11-28 | 2015-03-25 | 北京邮电大学 | Conversion device and method for transmitting signals in mixed mode |
| CN111327349B (en) * | 2018-12-12 | 2021-08-24 | 航天信息股份有限公司 | Vehicle identification method and RFID reader-writer |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102184431A (en) * | 2011-04-27 | 2011-09-14 | 深圳市远望谷信息技术股份有限公司 | Method and device for removing self-interference from passive radio frequency identification reader-writer |
| EP2375363A1 (en) * | 2010-04-08 | 2011-10-12 | Nxp B.V. | Non-contact communication device and method of operating the same |
| CN102915454A (en) * | 2012-10-23 | 2013-02-06 | 深圳市华士精成科技有限公司 | Counteracting method and counteracting circuit for carrier wave of ultrahigh-frequency radio frequency identification device (RFID) reader-writer |
-
2014
- 2014-04-30 CN CN201410182802.9A patent/CN104008409B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2375363A1 (en) * | 2010-04-08 | 2011-10-12 | Nxp B.V. | Non-contact communication device and method of operating the same |
| CN102184431A (en) * | 2011-04-27 | 2011-09-14 | 深圳市远望谷信息技术股份有限公司 | Method and device for removing self-interference from passive radio frequency identification reader-writer |
| CN102915454A (en) * | 2012-10-23 | 2013-02-06 | 深圳市华士精成科技有限公司 | Counteracting method and counteracting circuit for carrier wave of ultrahigh-frequency radio frequency identification device (RFID) reader-writer |
Also Published As
| Publication number | Publication date |
|---|---|
| CN104008409A (en) | 2014-08-27 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN104008415B (en) | A kind of self-interference elimination circuit | |
| CN104008414B (en) | By the passive RFID system of the high receiving sensitivity of optical link connection | |
| CN103218644B (en) | A kind of super high frequency electronic label read/write of carrier wave cancellation | |
| CN101599790B (en) | Intelligent micropower optical fiber wireless covering system | |
| US20090196373A1 (en) | System for increasing rfid tag reader sensitivity | |
| CN202472702U (en) | Radio frequency front system for ultrahigh frequency RFID reader-writer | |
| CN103226720B (en) | A kind of carrier wave cancellation method of super high frequency electronic label read/write | |
| CN102184431B (en) | Method and device for removing self-interference from passive radio frequency identification reader-writer | |
| CN206004673U (en) | Radio frequency signal power detection circuit | |
| CN103295036B (en) | The super high frequency electronic label read/write of a kind of phase-locked carrier wave cancellation and cancellation method thereof | |
| CN107707264A (en) | Power detection feedback circuit and method | |
| CN103297157A (en) | Antenna detecting method for multi-antenna ultrahigh-frequency radiofrequencyidentification reader-writer | |
| CN104008409B (en) | The optical link of antenna and reader is connected in passive RFID system | |
| CN104484690A (en) | Carrier cancelling circuit system for removing carrier jamming of receiving loop | |
| CN102281113A (en) | Communication relay device and standing-wave ratio detection device and method thereof | |
| CN207652434U (en) | Super high frequency radio frequency discriminatory carrier two-stage offsets processing circuit | |
| CN104009776A (en) | Interference elimination device and method | |
| CN106877899B (en) | A kind of RFID reader carrier wave leakage elimination system | |
| CN108282171B (en) | Self-interference offset device and electronic license plate reader-writer | |
| CN208622108U (en) | A kind of adaptive feed-through nulling system | |
| CN107146956B (en) | Antenna element and MIMO antenna system using codebook | |
| CN208723878U (en) | Rfid transmissions power control circuit | |
| CN104036305B (en) | RFID reader-writer and method for carrying out self-detection and self-adjustment on transmitting power | |
| KR100886666B1 (en) | System and method for controlling transmission power in rfid reader | |
| CN103235962B (en) | A kind of elimination launches the super high frequency electronic label read/write disturbed |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |