CN202134018U - Radio frequency identification system - Google Patents

Radio frequency identification system Download PDF

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Publication number
CN202134018U
CN202134018U CN201120076796U CN201120076796U CN202134018U CN 202134018 U CN202134018 U CN 202134018U CN 201120076796 U CN201120076796 U CN 201120076796U CN 201120076796 U CN201120076796 U CN 201120076796U CN 202134018 U CN202134018 U CN 202134018U
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CN
China
Prior art keywords
signal
frequency
frequency division
carried
digital
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CN201120076796U
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Chinese (zh)
Inventor
高怀
李昕
郭瑜
张晓东
钱罕杰
卞新海
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苏州英诺迅科技有限公司
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Priority to CN201120076796U priority Critical patent/CN202134018U/en
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Publication of CN202134018U publication Critical patent/CN202134018U/en

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Abstract

The utility model discloses an RFID system; and a local oscillator module in the system is a frequency synthesizer of decimal frequency division. The frequency synthesizer of decimal frequency division is a frequency synthesizer of decimal frequency division based on delta-sigma modulation technology. The RFID system disclosed by an embodiment of the utility model adopts the frequency synthesizer of decimal frequency division as the local oscillator module; a principle of the frequency synthesizer of decimal frequency division is used; a decimal part F needed by decimal frequency division is added on an input end of a delta-sigma modulator; the modulator generates pulse to control a frequency dividing ratio of a frequency synthesizer, so as to realize the purpose of decimal frequency division; multi-mode compensation is carried out by the delta-sigma modulator; sawtooth phase disturbance caused by periodicity transformation of the frequency dividing ratio is improved; a spurious signal is effectively inhibited; and the problem of large influence of phase noise in the conventional RFID system is improved.

Description

A kind of radio-frequency recognition system

Technical field

The utility model relates to the radio-frequency technique field, relates in particular to a kind of radio-frequency recognition system.

Background technology

REID (RFID technology) is a kind of noncontact two-way communication technology of utilizing RF-wise to carry out.This technology need not manual intervention when discerning work, and is swift and convenient to operate.Along with the progressively maturation of RFID technology, this technology is applied among container, tray, the packing of product, Intelligent Recognition ID card, books and the DVD more and more.Along with the expansion of application, also increasingly high to the requirement of each performance index of rfid system, especially to the requirement of local vibration source phase noise.The phase noise of local vibration source is very important performance index, and its performance impact to rfid system is very big.No matter frequency source is to do the emission pumping signal; Still do the receiver local oscillation signal or as various frequency references; Its entrained phase noise will equally appear at the demodulation terminal in the demodulating process neutralisation signals, cause that the base band signal to noise ratio (S/N ratio) descends problems such as bit error rate increase.In addition, the other important indicator of rfid system is limited by phase noise all like dynamic range, receiving sensitivity etc.

Rfid system generally includes: receiving cable and transmission channel, and receiving cable comprises: the LNA low noise amplifier, the signal that system is received carries out amplification filtering; The local oscillator module; Be used to provide local oscillation signal; Detuner with the signal after local oscillation signal and the amplification of LNA low noise amplifier carries out mixing carries out analog-to-digital analog to digital conversion AD module with the signal after the mixing, the baseband portion that the signal after the reception analog to digital conversion is handled; Transmission channel comprises: the digital-to-analog conversion DA module of baseband signal being carried out digital-to-analog conversion; The modulator that signal and local oscillation signal after the conversion are carried out mixing, the PA power amplifier that the signal after the mixing is amplified, the antenna that the signal after the amplification is sent.

Usually adopt the integral frequency divisioil frequency synthesizer as the local oscillator module, for system provides local oscillation signal in the UHF of the super high frequency radio frequency identification at present rfid system.The integral frequency divisioil frequency synthesizer is simple in structure, is easy to realize.But the minimum frequency resolution of integral frequency divisioil frequency synthesizer equates with the phase demodulation frequency of loop, therefore for obtaining the phase demodulation frequency that high resolving power must reduce loop, can make the corresponding deterioration of phase noise.

The utility model content

In view of this, the utility model provides a kind of rfid system, to solve the big problem of phase noise influence in the rfid system of the prior art.Its concrete scheme is following:

A kind of radio-frequency recognition system, the local oscillator module in the said system is a broken number frequency division synthesizer.

Preferably, said broken number frequency division synthesizer is the broken number frequency division synthesizer based on ∑-Δ modulation technique.

Preferably, said system also comprises:

Received RF signal, and with the low noise amplifier LNA of its amplification;

The detuner that the local oscillation signal that utilizes said local oscillator module to provide the radiofrequency signal after amplifying carries out demodulation;

Local oscillation signal after the said demodulation is amplified, and obtain the quadrature I/Q amplification delivery module of the signal mode value after the amplification;

Said mould value is carried out analog-to-digital analog to digital conversion AD module;

The baseband portion of the signal after the reception analog to digital conversion;

The digital-to-analog conversion DA module that the baseband signal that baseband portion is sent is carried out digital-to-analog conversion;

The modulator that utilizes said local oscillation signal to modulate the baseband signal after the digital-to-analog conversion;

The power amplifier PA that signal after the said modulation is amplified;

Modulation signal after amplifying is carried out antenna transmission.

Preferably, said broken number frequency division synthesizer based on ∑-Δ modulation technique comprises:

Produce the modulator of modulating pulse, receive modulating pulse, carry out the frequency divider of frequency division according to the frequency dividing ratio that pre-sets;

The reference frequency that frequency signal that frequency divider is provided and crystal oscillator provide compares, and the phase detector that converts the frequency and the phase differential of two signals into potential pulse;

The pulse that provides according to said phase detector generates the charge pump of push-and-pull electric current, and the push-and-pull electric current of said charge pump output is carried out filtering, is converted into the low-pass filter of the VT that carries phase information;

Under the control of said VT, export the voltage controlled oscillator of the frequency signal corresponding with VT, said frequency signal is imported said frequency divider.

Preferably, also comprising: control system launches/or receive the switch of signal.

Preferably, also comprise: be arranged at said LNA front end, first wave filter that the radiofrequency signal that receives is carried out filtering.

Preferably, also comprise: be arranged between said low noise amplifier LNA and the detuner second wave filter that the radiofrequency signal after amplifying is carried out filtering.

Preferably, also comprise:

Link to each other the prime driver that said modulation signal is amplified with the output terminal of said modulator;

Link to each other the attenuator that the modulation signal after the said amplification is decayed according to system requirements with said prime driver output end.

Can find out that from above-mentioned technical scheme the disclosed rfid system of the utility model embodiment adopts broken number frequency division synthesizer as the local oscillator module; Utilize the principle of broken number frequency division synthesizer; The fraction part F that fractional frequency division is required is added to the input end of sigma-delta modulator, produces the frequency dividing ratio that the controlled frequency compositor is removed in pulse by modulator, thereby realizes the purpose of fractional frequency division; And carry out multimode compensation by sigma-delta modulator; The sawtooth property phase perturbation that improvement is caused by the periodicity conversion of frequency dividing ratio suppresses spurious signal effectively, has improved the big problem of phase noise influence in the existing rfid system.

Description of drawings

In order to be illustrated more clearly in the utility model embodiment or technical scheme of the prior art; To do to introduce simply to the accompanying drawing of required use in embodiment or the description of the Prior Art below; Obviously, the accompanying drawing in describing below only is some embodiment of the utility model, for those of ordinary skills; Under the prerequisite of not paying creative work, can also obtain other accompanying drawing according to these accompanying drawings.

Fig. 1 is the structural representation of the disclosed rfid system of the utility model embodiment;

Fig. 2 is the structural representation of the disclosed another rfid system of the utility model embodiment;

Fig. 3 is the structural representation of the disclosed broken number frequency division synthesizer based on ∑-Δ modulation technique of the utility model embodiment.

Embodiment

To combine the accompanying drawing among the utility model embodiment below, the technical scheme among the utility model embodiment is carried out clear, intactly description, obviously, described embodiment only is the utility model part embodiment, rather than whole embodiment.Based on the embodiment in the utility model, those of ordinary skills are not making the every other embodiment that is obtained under the creative work prerequisite, all belong to the scope of the utility model protection.

The utility model discloses a kind of rfid system; Its structure is as shown in Figure 1; Comprise: low noise amplifier LNA11, detuner 12, analog to digital conversion AD module 13, baseband portion 14, digital-to-analog conversion DA module 15, modulator 16, antenna 17, power amplifier PA18, quadrature I/Q amplify delivery module 19 and local oscillator module; Wherein, The local oscillator module is a broken number frequency division synthesizer 110, and the broken number frequency division synthesizer 110 in the present embodiment is the broken number frequency division synthesizer based on ∑-Δ modulation technique, under the reference frequency effect that crystal oscillator 10 produces, generates local oscillation signal.

Further; LNA links to each other with antenna through switch 111 with power amplifier, selects current system to be in accepting state or emission state through switch, and the front end of LNA is provided with first wave filter 112; Be used for clutter in the signal that filtering receives, to guarantee quality of signals.

Its principle of work is described below:

The broken number frequency division synthesizer that adopts ∑-Δ modulation technique is the reception of rfid system and launches two passages local oscillation signal is provided; In receiving cable; The received radiofrequency signal of rfid system is being amplified through getting into low noise amplifier LNA11 after the filtering; The local oscillation signal mixing in detuner 12 that is provided as the local oscillator module with the broken number frequency division synthesizer 110 that adopts ∑-Δ modulation technique; Utilize local oscillation signal to carry out demodulation and output the signal that receives, quadrature I/Q amplifies the local oscillation signal of delivery module after with demodulation and amplifies, and obtains the mould value of the signal after the amplification; After this mould value carried out analog to digital conversion through the AD module, get into baseband portion 14 and handle; In transmission channel; The baseband signal that baseband portion 14 is exported after carrying out digital-to-analog conversion through the DA module with local oscillation signal mixing in modulator 16; Utilize local oscillation signal to modulate and export baseband signal, the signal after the modulation utilizes antenna 17 to launch after amplifying via PA18.

It is as shown in fig. 1 that present embodiment does not limit RFID, has the passage of transmitting and receiving simultaneously, same, also can obtain the local oscillation signal of single channel output as required with the perhaps single-ended output circuit configuration of balun circuit.Ba Lun can be built by discrete component, also can adopt integrated component to make up.Equally do not limit the broken number frequency division synthesizer of employing ∑-Δ modulation technique yet, equally can adopt the broken number frequency division synthesizer of other types yet.

The disclosed rfid system of present embodiment; Because the broken number frequency division synthesizer that adopts ∑-Δ modulation technique as the local oscillator module, through peripheral circuit and the loop filtering bandwidth that broken number frequency division synthesizer rationally is set, can obtain short frequency hopping step-length; So can obtain desirable phase noise; Reduce the influence of phase noise, improve receiving sensitivity and dynamic range, and improve receiving range system.Owing to improved phase noise, improve the signal to noise ratio (S/N ratio) of acknowledge(ment) signal simultaneously, further reduced the bit error rate, greatly improved the performance of system.

Shown in Figure 2 is the structural representation of the disclosed another rfid system of the utility model; Except that comprising that each is module shown in Fig. 1; Also comprise: the prime driving amplifier 113 that links to each other with the output terminal of modulator 16, and the attenuator 114 that links to each other with the output terminal of prime driving amplifier 113.Both are used; At first modulation signal is amplified through prime driver 113; Utilize attenuator 114 then, the modulation signal after amplifying is had the decay of control according to the needs of system, make output power can remain in the predefined scope.

Further, can also comprise second wave filter 115 that the signal after the LNA amplification is carried out filtering once more,, guarantee that further the signal that is input in the detuner can not be interfered, improve the quality of restituted signal with the clutter in the filtering amplifying signal.

Further, the structure based on the broken number frequency division synthesizer of ∑-Δ modulation technique in the present embodiment is as shown in Figure 3, comprising: modulator 21, frequency divider 22, phase detector 23, charge pump 24, low-pass filter 25 and voltage controlled oscillator 26.

Wherein fref is the reference frequency signal that crystal oscillator provided in the rfid system; This reference frequency signal exports phase detector 23 to behind frequency multiplier/frequency divider 27 frequencys multiplication or frequency division; As the frequency of operation fPFD of phase detector 23, this frequency of operation is the reference frequency of phase detector 23.Phase detector 23 compares frequency f N and this reference frequency fPFD of frequency divider 22 output, converts the frequency of two signals and phase differential into proportional with it pulse and exports, and offers charge pump 24.When the phase differential of fPFD and fN is correct time, the positive potential pulse of phase detector 23 outputs, when the phase differential of fPFD and fN when negative, the negative potential pulse of phase detector 23 outputs, identical as if fPFD with the phase place of fN, then not output voltage pulse.

Charge pump 24 is released a certain amount of electric current after it receives the positive voltage pulse of phase detector 23 according to received potential pulse output push-and-pull electric current, behind the negative voltage pulse that receives phase detector 23, a certain amount of electric current is sucked.The push-and-pull electric current of charge pump 24 outputs carries the phase information of fPFD and fN, and this signal is removed the spurious signal that phase detector 23 brings, and is converted into the VT that carries phase information after low-pass filter 25 filtering.Under the control of this voltage, the corresponding frequency signal of voltage controlled oscillator 26 outputs.

Most of signal of voltage controlled oscillator 26 is directly exported, and is the required local oscillation signal RFout of modulation module in the rfid system.Another part signal fLO sends into frequency divider.FLO gets into frequency divider, carry out frequency division according to the frequency dividing ratio that pre-sets after, export phase detector to and reference frequency fPFD compares.

When the frequency of the local oscillation signal RFout of this decimal frequency divider output is not setting value; Signal fN and the phase demodulation frequency fPFD of fLO behind frequency division is not inconsistent; Phase detector 23 will contain the signal output of phase information; VT through charge pump 24 adjustment voltage controlled oscillators 26 changes the output frequency of voltage controlled oscillator thereupon.Output frequency up to voltage controlled oscillator 26 arrives setting value, and fN is identical with fPFD, and phase detector 23 is no longer exported signal, and decimal frequency divider reaches steady state (SS), for system provides stable local oscillation signal.

Each embodiment adopts the mode of going forward one by one to describe in this instructions, and what each embodiment stressed all is and the difference of other embodiment that identical similar part is mutually referring to getting final product between each embodiment.For the disclosed device of embodiment, because it is corresponding with the embodiment disclosed method, so description is fairly simple, relevant part is partly explained referring to method and is got final product.

To the above-mentioned explanation of the disclosed embodiments, make this area professional and technical personnel can realize or use the utility model.Multiple modification to these embodiment will be conspicuous concerning those skilled in the art, and defined General Principle can realize under the situation of spirit that does not break away from the utility model or scope in other embodiments among this paper.Therefore, the utility model will can not be restricted to these embodiment shown in this paper, but will meet and principle disclosed herein and features of novelty the wideest corresponding to scope.

Claims (7)

1. a radio-frequency recognition system is characterized in that, the local oscillator module in the said system is a broken number frequency division synthesizer, and said system also comprises:
Received RF signal, and with the low noise amplifier LNA of its amplification;
The detuner that the local oscillation signal that utilizes said local oscillator module to provide the radiofrequency signal after amplifying carries out demodulation;
Signal after the said demodulation is amplified, and obtain the quadrature I/Q amplification delivery module of the signal mode value after the amplification;
Said mould value is carried out analog-to-digital analog to digital conversion AD module;
The baseband portion of the signal after the reception analog to digital conversion;
The digital-to-analog conversion DA module that the baseband signal that baseband portion is sent is carried out digital-to-analog conversion;
The modulator that utilizes said local oscillation signal to modulate the baseband signal after the digital-to-analog conversion;
The power amplifier PA that signal after the said modulation is amplified;
Modulation signal after amplifying is carried out antenna transmission.
2. system according to claim 1 is characterized in that, said broken number frequency division synthesizer is the broken number frequency division synthesizer based on ∑-△ modulation technique.
3. system according to claim 2 is characterized in that, said broken number frequency division synthesizer based on ∑-△ modulation technique comprises:
Produce the modulator of modulating pulse, receive modulating pulse, carry out the frequency divider of frequency division according to the frequency dividing ratio that pre-sets;
The reference frequency that frequency signal that frequency divider is provided and crystal oscillator provide compares, and the phase detector that converts the frequency and the phase differential of two signals into potential pulse;
The pulse that provides according to said phase detector generates the charge pump of push-and-pull electric current, and the push-and-pull electric current of said charge pump output is carried out filtering, is converted into the low-pass filter of the VT that carries phase information;
Under the control of said VT, export the voltage controlled oscillator of the frequency signal corresponding with VT, said frequency signal is imported said frequency divider.
4. system according to claim 2 is characterized in that, also comprises: control system launches/or receive the switch of signal.
5. system according to claim 4 is characterized in that, also comprises: be arranged at said LNA front end, first wave filter that the radiofrequency signal that receives is carried out filtering.
6. system according to claim 5 is characterized in that, also comprises: be arranged between said low noise amplifier LNA and the detuner second wave filter that the radiofrequency signal after amplifying is carried out filtering.
7. system according to claim 6 is characterized in that, also comprises:
Link to each other the prime driver that said modulation signal is amplified with the output terminal of said modulator;
Link to each other the attenuator that the modulation signal after the said amplification is decayed according to system requirements with said prime driver output end.
CN201120076796U 2011-03-22 2011-03-22 Radio frequency identification system CN202134018U (en)

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Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102693433A (en) * 2011-03-22 2012-09-26 苏州英诺迅科技有限公司 Radio frequency identification system
CN102831448A (en) * 2012-05-18 2012-12-19 睿芯联科(北京)电子科技有限公司 Radio frequency identification device
CN103595643A (en) * 2013-11-13 2014-02-19 深圳创维-Rgb电子有限公司 Router and smart home control system
CN104380611A (en) * 2012-05-29 2015-02-25 泰格信息技术有限公司 Apparatus for generating dedicated data channels in inductive coupled RFID
US10079704B2 (en) 2014-09-22 2018-09-18 Drnc Holdings, Inc. Transmission apparatus for a wireless device using delta-sigma modulation
CN110365350A (en) * 2019-06-24 2019-10-22 成都振芯科技股份有限公司 Receiving channel quadrature alignment algorithm adaptability Enhancement Method and device

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102693433A (en) * 2011-03-22 2012-09-26 苏州英诺迅科技有限公司 Radio frequency identification system
CN102831448A (en) * 2012-05-18 2012-12-19 睿芯联科(北京)电子科技有限公司 Radio frequency identification device
CN102831448B (en) * 2012-05-18 2015-09-09 睿芯联科(北京)电子科技有限公司 A kind of rfid device
CN104380611A (en) * 2012-05-29 2015-02-25 泰格信息技术有限公司 Apparatus for generating dedicated data channels in inductive coupled RFID
CN104380611B (en) * 2012-05-29 2016-06-15 泰格信息技术有限公司 For producing the device of dedicated data channel in the RFID of inductive
CN103595643A (en) * 2013-11-13 2014-02-19 深圳创维-Rgb电子有限公司 Router and smart home control system
US10079704B2 (en) 2014-09-22 2018-09-18 Drnc Holdings, Inc. Transmission apparatus for a wireless device using delta-sigma modulation
US10419254B2 (en) 2014-09-22 2019-09-17 Drnc Holdings, Inc. Transmission apparatus for a wireless device using delta-sigma modulation
CN110365350A (en) * 2019-06-24 2019-10-22 成都振芯科技股份有限公司 Receiving channel quadrature alignment algorithm adaptability Enhancement Method and device

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