CN105930755A - Multipath identification method and system of passive wireless surface acoustic wave devices - Google Patents
Multipath identification method and system of passive wireless surface acoustic wave devices Download PDFInfo
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- CN105930755A CN105930755A CN201610229359.5A CN201610229359A CN105930755A CN 105930755 A CN105930755 A CN 105930755A CN 201610229359 A CN201610229359 A CN 201610229359A CN 105930755 A CN105930755 A CN 105930755A
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- G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
- G06K7/00—Methods or arrangements for sensing record carriers, e.g. for reading patterns
- G06K7/10—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation
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Abstract
The invention discloses a multipath identification method and system of passive wireless surface acoustic wave devices. The method comprises the steps of (11) sending an inquiry signal, in which a reader sends an RF inquiry signal after phase modulation by inquiry codes and carrier waves; (12) receiving reflection signals, in which the reader receives reflection signals of the surface acoustic wave devices; (13) identifying pulse signals, in which the reader determines whether peak pulses exist in the reflection signals, and if yes, the surface acoustic wave device matching the inquiry codes exists in an action area of the reader; and (14) extracting phase information, in which the reader extracts phase information of the pulse signals by demodulation, and further reads information of the surface acoustic wave device matching the inquiry codes. The system comprises the reader (100) and the surface acoustic wave devices (200). According to the method and system, the surface acoustic wave devices can be read in multiple paths via the CDMA technology when the reflection signals are asynchronous.
Description
Technical field
The invention belongs to surface acoustic wave applied technical field, particularly one can be to multiple passive wireless acoustic surface wave device
It is identified and the method and system of information reading.
Background technology
The electronic device that SAW device is i.e. operated based on surface acoustic wave propagation characteristic on piezoelectric substrate, its bag
Include surface acoustic wave sensor, SAW ID-tag (transponder), surface acoustic wave executor etc..Owing to surface acoustic wave is passing
During broadcasting and changing, the energy of loss is the least so that SAW device can directly receive electromagnetic wave signal by antenna
And it is converted into surface acoustic wave, also can realize conversion and the conversion of signal need not external power source in the case of powering, therefore,
SAW device can realize non-active operation and be wirelessly transferred.SAW device in addition to the operating characteristic of passive and wireless,
Also have that reliability is high, environmental suitability strong, simple in construction, the application advantage such as flexibly, information sensing, article identification,
The fields such as signal processing are widely used.
The real application systems of passive wireless acoustic surface wave device is typically by a reader (interrogator) and multiple sound surface
Wave device forms.During work, SAW device receives, by antenna, the radio interrogation signal that reader is launched, and by comb
Tooth transducer is converted into surface acoustic wave, and surface acoustic wave is propagated on piezoelectric substrate, runs into after reflecting grating reflects and passes to
Transducer, or it is passed directly to another group transducer, comb transducer is anti-by antenna after surface acoustic wave is converted into the signal of telecommunication
Being emitted back towards reader, reader realizes the identification to SAW device and information reading by carrying out reflected signal processing.
Simple in construction because of passive wireless acoustic surface wave device so that the communication process between SAW device and reader
In do not have complexity transmission medium access control mechanisms, cause multiple SAW device reflected signal arrive reader time
Can interfere with each other, thus cause reader can not identify and reading device information, here it is passive wireless acoustic surface wave device
Multichannel identification and multiline message read problem.Actual available SAW device multichannel identification and read method master
Time division multiplex to be included, frequency division multiplexing and CDMA.Time division multiplex and frequency multiplexing technique comparative maturity, but be subject to
To device size and the restriction of frequency spectrum resource so that the negligible amounts of the SAW device that reader can read simultaneously.Code
The multiple signals that the premise that division multiple access technology can be applied is orthogonal have synchronicity, then carry out related operation and come multichannel
Signal resolves.Different yet with signal propagation delay so that the reflected signal of each SAW device arrives to be read
Can not synchronize during device.
Therefore, prior art there is the problem that CDMA cannot realize reflected signal asynchronous time surface acoustic wave device
The multichannel of part reads.
Summary of the invention
It is an object of the invention to provide a kind of passive wireless acoustic surface wave device multichannel recognition methods, by CDMA skill
Art realize reflected signal asynchronous time SAW device multichannel read.
Another object of the present invention is to provide a kind of and realize above-mentioned passive wireless acoustic surface wave device multichannel recognition methods
System.
A kind of technical scheme realizing the object of the invention is:
A kind of passive wireless acoustic surface wave device multichannel recognition methods a, it is adaptable to reader is to multiple SAW devices
Identification and information read, comprise the steps:
(11) interrogation signal is sent: reader transmitting is carried out the radio interrogation letter after phase-modulation by inquiry coding and carrier wave
Number；
(12) reflected signal is received: reader receives the reflected signal from each SAW device, and this reflected signal is
Interrogation signal and SAW device coding carry out the electromagnetic wave signal after computing cross-correlation；
(13) pulse signal is identified: reader differentiates in reflected signal whether there is spike, in this way, then reader
The SAW device with inquiry codes match is there is in the zone of action；
(14) phase information is extracted: reader, by demodulation, extracts the phase information of pulse signal, thus reads and ask
Ask the information of the SAW device of codes match.
The another kind of technical scheme realizing the object of the invention is:
A kind of passive wireless acoustic surface wave device multichannel recognition methods, it is adaptable to multiple SAW devices are to same reading
The response of device, comprises the steps:
(21) receive interrogation signal: SAW device receive by inquiry coding and carrier phase modulate from readding
Read the radio interrogation signal of device；
(22) related operation is carried out: it is mutual with what self encoded that SAW device utilizes correlator on sheet to realize interrogation signal
Related operation；
(23) reflected signal is launched: SAW device is by the computing cross-correlation result conversion of interrogation signal with self coding
For electromagnetic wave signal and launch, for reader identification and information retrieval.
The technical scheme realizing another object of the present invention is:
A kind of passive wireless acoustic surface wave device multichannel identification system, including a reader and multiple SAW device,
Described reader includes:
Interrogation signal transmitting element (101), is carried out the radio interrogation after phase-modulation for launching by inquiry coding and carrier wave
Signal；
Reflected signal receives unit (102), for receiving the reflected signal from each SAW device, this reflected signal
The electromagnetic wave signal after computing cross-correlation is carried out for interrogation signal and SAW device coding；
Pulse signal recognition unit (103), is used for differentiating in reflected signal whether there is spike, in this way, then reads
The SAW device with inquiry codes match is there is in the device zone of action；
Phase information extraction unit (104), for by demodulation, extract pulse signal phase information, thus read with
The information of the SAW device of inquiry codes match.
Compared with prior art, its remarkable advantage is the present invention:
The related operation of CDMA is transferred on SAW device end by the present invention by reader end, thus solves
The asynchronism of each device reflected signal causes can not the problem of quadrature decoder.Therefore, achieve based on CDMA
When reflected signal is asynchronous, the multichannel of SAW device reads.
The correlator connection organizing interdigital transducer, the simple cost of device architecture on the sheet of the method for the present invention more
Low it is easily achieved.
The Part Number of the method for the invention enriches, and the number of devices that individual system comprises is big, and application is flexibly.
To sum up, method of the present invention can efficiently solve the identification that a large amount of passive wireless acoustic surface wave device works simultaneously
Read problem with information, in the field such as RF identification and distributed monitoring, there is huge application potential.
Accompanying drawing explanation
Fig. 1 is passive wireless acoustic surface wave device multichannel identification system structure schematic diagram of the present invention.
Fig. 2 is dual-port device schematic diagram based on SAW correlator.
Fig. 3 is one port devices schematic diagram based on SAW correlator.
Fig. 4 is the fundamental diagram of passive wireless acoustic surface wave device multichannel recognition methods of the present invention.
In figure, reader 100, interrogation signal transmitting element 101, reflected signal receives unit 102, pulse signal identification
Unit 103, phase information extraction unit 104, reader antenna 105,
SAW device 200, interrogation signal receives unit 201, signal correction arithmetic element 202, and reflected signal is launched
Unit 203, piezoelectric substrate 204, interdigital transducer 205, correlator 206, busbar 207, device antenna 208,
Reception antenna 209, transmission antenna 210, Part Number 211, the surface acoustic wave signal 212 of interrogation signal conversion, mutually
The surface acoustic wave signal 213 of OFF signal conversion.
Detailed description of the invention
As it is shown in figure 1, one passive wireless acoustic surface wave device multichannel identification system of the present invention, including a reader 100
With multiple SAW devices 200, described reader 100 includes:
Interrogation signal transmitting element 101, is carried out the radio interrogation letter after phase-modulation for launching by inquiry coding and carrier wave
Number；
Reflected signal receives unit 102, and for receiving the reflected signal from each SAW device, this reflected signal is
Interrogation signal and SAW device coding carry out the electromagnetic wave signal after computing cross-correlation；
Pulse signal recognition unit 103, is used for differentiating in reflected signal whether there is spike, in this way, then and reader
The SAW device with inquiry codes match is there is in the zone of action；
Phase information extraction unit 104, for by demodulation, extracts the phase information of pulse signal, thus reads and ask
Ask the information of the SAW device of codes match.
Described SAW device 200 includes:
Interrogation signal receives unit 201, for receiving the radio interrogation signal from reader 100；
Signal correction arithmetic element 202, for realizing the computing cross-correlation of interrogation signal and self coding；
Reflected signal transmitter unit 203, for being converted to electromagnetism by the computing cross-correlation result of interrogation signal with self coding
Ripple signal is also launched, for reader identification and information retrieval.
The signal correction arithmetic element 202 of described SAW device 200 includes by the interdigital transducer organizing opposed polarity more
Correlator 206 on the sheet composed in parallel, in described upper correlator 206, the connecting mode of interdigital transducer determines this sound table
The coding of face wave device.
The electronic device of interdigital transducer 205 it is coated with on SAW device 200 generally piezoelectric substrate 204.Work
Time, reader 100 launches radio interrogation signal by antenna 105, after each device receives interrogation signal by antenna 208
Be converted to surface acoustic wave signal by interdigital transducer 205 and propagate on substrate 204 surface.Surface acoustic wave is in communication process
Meet interdigital transducer 205 be converted to again electromagnetic signal and launch as reflected signal, reader 100 through antenna 208
Carry out signal analysis and processing after receiving the reflected signal of each device 200, thus realize the identification to each device 200 and information
Read.
Due to the equal reflected signal of all SAW devices in reader interrogation signal coverage, reader receives
Be the asynchronous superposition of each reflected signal so that create strong interference between each device reflected signal, thus cause readding
Read device cannot each device be identified and information reading.In order to solve to interfere problem between reflected signal, this
Bright employing SAW correlator technology, makes interrogation signal and Part Number do computing cross-correlation at device end, and by computing
Result feeds back to reader with reflected signal form.Owing to only just can produce obvious point with the device of inquiry codes match
Peak pulse, therefore the SAW device of coupling can be identified by reader and information reads.When reader will coding
In collection, all codings all send one by one with the form of interrogation signal, then can realize the identification to devices all in system and information
Read.
A kind of embodiment schematic diagram of SAW device is as in figure 2 it is shown, this device is mainly by substrate 204, interdigital transducing
Device 205, correlator 206, reception antenna 209, transmission antenna 210 form.Interdigital transducer 205 for the signal of telecommunication with
Conversion between surface acoustic wave signal.Correlator 206 is to be composed in parallel by the interdigital transducer organizing opposed polarity more, homopolarity
Property presentation code "+1 ", heteropolarity presentation code "-1 ", then Part Number 211 is by group interdigital transducer each in 206
Connection form determines, often organizes the chip lengths that periodicity is Part Number 211 of interdigital transducer, thus can realize device
Coding and the computing cross-correlation of input signal.During work, antenna 209 receives and is modulated with the interrogation signal of inquiry coding and transmits
To interdigital transducer 205,205 convert the electrical signal to surface acoustic wave signal 212 and propagate along substrate, and surface acoustic wave is believed
Numbers 212 input correlators 206 carry out computing cross-correlation with Part Number 211, and operation result is in electrical signal form by converging
Stream bar 207 is delivered to antenna 210 and launches, and therefore this device is dual-port device.
The another kind of embodiment schematic diagram of SAW device as it is shown on figure 3, this device is similar with above-mentioned dual-port device,
Main by substrate 204, interdigital transducer 205, correlator 206 and antenna 208 form, and difference is transducer
205 are connected in parallel by busbar 207 with correlator 206, and are connected with antenna 208, and antenna 208 is both for receiving
Antenna is again for launching antenna, and therefore this device is one port devices.During work, antenna 208 receives and is modulated with inquiry coding
Interrogation signal is also delivered separately to interdigital transducer 205 and correlator 206 by busbar 207.In 205 sides, change
Can convert the electrical signal to surface acoustic wave signal 212 and propagate along substrate by device 205, surface acoustic wave signal 212 input is relevant
Device 206 and Part Number 211 carry out computing cross-correlation, and operation result flows into busbar 207 in electrical signal form.206
Side, correlator 206 realizes the computing cross-correlation between input signal and Part Number 211, and operation result is converted to sound
Surface wave 213 is also propagated along substrate, and signal 213 is converted into the signal of telecommunication and flows into busbar after arriving transducer 205
207.Owing to the transformation results of both sides signal is consistent, 205 and 206 both sides import the signal of busbar 207 and can realize same
It is stacked adduction to be launched by antenna 208.
As shown in Figure 4, passive wireless acoustic surface wave device multichannel recognition methods of the present invention a, it is adaptable to reader 100
Identification and information to multiple SAW devices 200 are read, and comprise the steps:
(11) interrogation signal is sent: reader transmitting is carried out the radio interrogation letter after phase-modulation by inquiry coding and carrier wave
Number；
Described inquiry is encoded to binary coding.
(12) reflected signal is received: reader receives the reflected signal from each SAW device, and this reflected signal is
Interrogation signal and SAW device coding carry out the electromagnetic wave signal after computing cross-correlation；
SAW device is encoded to binary coding.
The computing cross-correlation that described (12) receive in reflected signal step is:
When the inquiry coding in interrogation signal is inconsistent with SAW device coding, reflected signal presents disordered state,
Show as noise；
When the inquiry coding in interrogation signal is consistent with SAW device coding, reflected signal presents a spike.
(13) pulse signal is identified: reader differentiates in reflected signal whether there is spike, in this way, then reader
The SAW device with inquiry codes match is there is in the zone of action；
(14) phase information is extracted: reader, by demodulation, extracts the phase information of pulse signal, thus reads and ask
Ask the information of the SAW device of codes match.
As shown in Figure 4, passive wireless acoustic surface wave device multichannel recognition methods of the present invention, it is adaptable to multiple surface acoustic wave devices
The part response to same reader, comprises the steps:
(21) receive interrogation signal: SAW device receive by inquiry coding and carrier phase modulate from readding
Read the radio interrogation signal of device；
(22) related operation is carried out: it is mutual with what self encoded that SAW device utilizes correlator on sheet to realize interrogation signal
Related operation；
(23) reflected signal is launched: SAW device is by the computing cross-correlation result conversion of interrogation signal with self coding
For electromagnetic wave signal and launch, for reader identification and information retrieval.
Inquiry is encoded to binary coding, and SAW device is encoded to binary coding.
Described (22) carry out the computing cross-correlation in related operation step:
When the inquiry coding in interrogation signal is inconsistent with SAW device coding, reflected signal presents disordered state,
Show as noise；
When the inquiry coding in interrogation signal is consistent with SAW device coding, reflected signal presents a spike.
Claims (9)
1. a passive wireless acoustic surface wave device multichannel recognition methods a, it is adaptable to reader is to multiple surface acoustic waves
The identification of device and information read, it is characterised in that comprise the steps:
(11) interrogation signal is sent: reader transmitting is carried out the radio interrogation letter after phase-modulation by inquiry coding and carrier wave
Number；
(12) reflected signal is received: reader receives the reflected signal from each SAW device, and this reflected signal is
Interrogation signal and SAW device coding carry out the electromagnetic wave signal after computing cross-correlation；
(13) pulse signal is identified: reader differentiates in reflected signal whether there is spike, in this way, then reader
The SAW device with inquiry codes match is there is in the zone of action；
(14) phase information is extracted: reader, by demodulation, extracts the phase information of pulse signal, thus reads and ask
Ask the information of the SAW device of codes match.
Multichannel recognition methods the most according to claim 1, it is characterised in that: described inquiry is encoded to binary system and compiles
Code, SAW device is encoded to binary coding.
Multichannel recognition methods the most according to claim 1, it is characterised in that described (12) receive reflected signal
Computing cross-correlation in step is:
When the inquiry coding in interrogation signal is inconsistent with SAW device coding, reflected signal presents disordered state,
Show as noise；
When the inquiry coding in interrogation signal is consistent with SAW device coding, reflected signal presents a spike.
4. a passive wireless acoustic surface wave device multichannel recognition methods, it is adaptable to multiple SAW devices are to same
The response of reader, it is characterised in that comprise the steps:
(21) receive interrogation signal: SAW device receive by inquiry coding and carrier phase modulate from readding
Read the radio interrogation signal of device；
(22) related operation is carried out: it is mutual with what self encoded that SAW device utilizes correlator on sheet to realize interrogation signal
Related operation；
(23) reflected signal is launched: SAW device is by the computing cross-correlation result conversion of interrogation signal with self coding
For electromagnetic wave signal and launch, for reader identification and information retrieval.
Multichannel recognition methods the most according to claim 4, it is characterised in that: inquiry is encoded to binary coding,
SAW device is encoded to binary coding.
Multichannel recognition methods the most according to claim 4, it is characterised in that: described (22) carry out related operation
Computing cross-correlation in step is:
When the inquiry coding in interrogation signal is inconsistent with SAW device coding, reflected signal presents disordered state,
Show as noise；
When the inquiry coding in interrogation signal is consistent with SAW device coding, reflected signal presents a spike.
7. a passive wireless acoustic surface wave device multichannel identification system, including a reader (100) and multiple sound table
Face wave device (200), it is characterised in that described reader (100) including:
Interrogation signal transmitting element (101), is carried out the radio interrogation after phase-modulation for launching by inquiry coding and carrier wave
Signal；
Reflected signal receives unit (102), for receiving the reflected signal from each SAW device, this reflected signal
The electromagnetic wave signal after computing cross-correlation is carried out for interrogation signal and SAW device coding；
Pulse signal recognition unit (103), is used for differentiating in reflected signal whether there is spike, in this way, then reads
The SAW device mated with interrogation signal is there is in the device zone of action；
Phase information extraction unit (104), for by demodulation, extract pulse signal phase information, thus read with
The information of the SAW device of interrogation signal coupling.
Multichannel identification system the most according to claim 7, it is characterised in that described SAW device (200)
Including:
Interrogation signal receives unit (201), for receiving the radio interrogation signal from reader (100)；
Signal correction arithmetic element (202), for realizing the computing cross-correlation of interrogation signal and self coding；
Reflected signal transmitter unit (203), for being converted to electricity by the computing cross-correlation result of interrogation signal with self coding
Magnetostatic wave signal is also launched, for reader identification and information retrieval.
Multichannel identification system the most according to claim 8, it is characterised in that described SAW device (200)
Signal correction arithmetic element (202) include correlator on the sheet that composed in parallel by the interdigital transducer organizing opposed polarity more
(206) change the connecting mode of interdigital transducer in correlator on sheet (206) described in, and determine the volume of this SAW device
Code.
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| WO2020215611A1 (en) * | 2019-04-26 | 2020-10-29 | 中北大学 | Multi-parameter surface acoustic wave sensing device, manufacturing method, and aircraft monitoring system |
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