Dual frequency differential read-write device and system

Abstract

The embodiment of the application provides a kind of dual-frequency differential reading and writing device and system.Therein device includes: antenna and reading and writing unit of electric connection;Reading and writing unit includes transmitting module and receiving module;Receiving module is configured as, receives uplink radio frequency signal one and uplink radio frequency signal two, obtains nominal sensing quantity one according to uplink radio frequency signal one, obtains nominal sensing quantity two according to uplink radio frequency signal two, obtains differential sensing quantity according to nominal sensing quantity one and nominal sensing quantity two;Wherein, the carrier frequency of uplink radio frequency signal one is frequency one, the carrier frequency of uplink radio frequency signal two is frequency two, and frequency one is different from frequency two.

Description

Technical Field

[0001] This application relates to the field of communication technology, and more specifically, to a dual-frequency differential read / write device and system. Background Technology

[0002] A tag, or electronic tag, is an electronic identifier attached to an object for automatic identification, tracking, and acquisition of information about that object. Tags can be functionally categorized into identification tags and sensing tags. They typically begin operating after receiving downlink radio frequency signals, while the resulting uplink radio frequency signals often operate at a single carrier frequency. Their performance is easily affected by the surrounding environment, such as strong background electromagnetic reflection and multipath effects. Summary of the Invention

[0003] To overcome the shortcomings of existing technologies, a dual-frequency differential read / write device and system are provided in order to solve the technical problems existing in the prior art.

[0004] To achieve the aforementioned objectives, this application adopts the following technical solution:

[0005] In a first aspect, a dual-frequency differential read / write device is provided, comprising: an antenna and a read / write unit electrically connected; the read / write unit includes a transmitting module and a receiving module; the receiving module is configured to receive an uplink radio frequency signal one and an uplink radio frequency signal two, obtain a nominal sensing quantity one based on the aforementioned uplink radio frequency signal one, obtain a nominal sensing quantity two based on the aforementioned uplink radio frequency signal two, and obtain a differential sensing quantity based on the nominal sensing quantity one and the nominal sensing quantity two; wherein the carrier frequency of the uplink radio frequency signal one is frequency one, and the carrier frequency of the uplink radio frequency signal two is frequency two, and frequency one and frequency two are different.

[0006] Furthermore, the aforementioned receiving module includes a duplexer, a frequency one analog processing module, a frequency two analog processing module, and a parsing module; the frequency one analog processing module and the frequency two analog processing module are electrically connected to the duplexer, and the frequency one analog processing module and the frequency two analog processing module are electrically connected to the parsing module.

[0007] Furthermore, the aforementioned frequency one analog processing module is used to obtain the IQ baseband signal of frequency one; the aforementioned frequency two analog processing module is used to obtain the IQ baseband signal of frequency two.

[0008] Furthermore, the aforementioned analysis module obtains the calculated value of frequency one based on the IQ baseband signal of frequency one; the aforementioned analysis module obtains the calculated value of frequency two based on the IQ baseband signal of frequency two.

[0009] Furthermore, the aforementioned transmitting module transmits a downlink radio frequency signal with a single carrier frequency, or transmits a downlink radio frequency signal comprising at least one frequency and a downlink radio frequency signal with two frequencies.

[0010] Furthermore, the aforementioned receiving module adopts a zero-IF architecture, a superheterodyne architecture, or a low-IF architecture.

[0011] Secondly, a dual-frequency differential read / write system is provided, comprising: a dual-frequency tag device, and any of the aforementioned dual-frequency differential read / write devices.

[0012] Furthermore, the aforementioned dual-frequency tag device includes an antenna, an impedance matching module, a first SAW resonator, and a second SAW resonator. The impedance matching module is electrically connected to the antenna, and both the first and second SAW resonators are electrically connected to the impedance matching module. The first SAW resonator operates at frequency one, and the second SAW resonator operates at frequency two.

[0013] Furthermore, the aforementioned dual-frequency tag device includes an antenna, a passive mixer unit, a frequency selection unit one, and a frequency selection unit two. Port one of the passive mixer unit is electrically connected to the antenna, port two of the passive mixer unit is electrically connected to the frequency selection unit one, and port three of the passive mixer unit is electrically connected to the frequency selection unit two. The operating frequencies of the frequency selection unit one and the frequency selection unit two are different.

[0014] Furthermore, the aforementioned passive mixer unit includes a transistor.

[0015] It is understood that, according to the technical solution of this application, a differential signal is obtained by using the dual-frequency uplink radio frequency signal generated by the tag, thereby solving the problems of poor demodulation accuracy and limited application scenarios caused by the inability to eliminate various interferences in a single uplink radio frequency signal. Attached Figure Description

[0016] Figure 1 This is one of the schematic diagrams of the dual-frequency differential read / write system according to an embodiment of this application;

[0017] Figure 2 This is a schematic diagram of the dual-frequency tag device based on the backscattering principle according to an embodiment of this application;

[0018] Figure 3 This is a second schematic diagram of the dual-frequency differential read / write system structure according to an embodiment of this application;

[0019] Figure 4 This is a schematic diagram of the dual-frequency tag device based on the passive frequency conversion principle according to an embodiment of this application.

[0020] Figure 5 This is a schematic diagram of the receiving module structure in the dual-frequency differential read / write device according to an embodiment of this application. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0022] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0023] In this article, the term "and / or" is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone.

[0024] The terms "first," "second," "object one," "object two," etc., used in the specification and drawings of this application are used to distinguish different objects or to distinguish different treatments of the same object, rather than to describe a specific order of objects.

[0025] Furthermore, the terms "comprising" and "having," and any variations thereof, used in the description of this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the steps or units listed, but may optionally include other steps or units not listed, or may optionally include other steps or units inherent to such process, method, product, or apparatus.

[0026] It should be noted that in the embodiments of this application, the words "in an example," "exemplary," or "for example" are used to indicate that they are examples, illustrations, or explanations. Any embodiment or design that is described as "in an example," "exemplary," or "for example" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or design options. Specifically, the use of the words "in an example," "exemplary," or "for example" is intended to present the relevant concepts in a specific manner.

[0027] It should be noted that, to save space, a single drawing in this application does not necessarily represent only a single embodiment or implementation method. Generally, a single drawing may be used to illustrate several embodiments or implementation methods. Functional components, connection relationships between components, or process steps that are not essential for certain embodiments will be indicated by dashed lines.

[0028] To facilitate understanding, the relevant technologies and concepts involved in the embodiments of this application will be introduced first.

[0029] Read / write device: also known as a reader, reading device, reader-writer, read / write apparatus, readout device, gateway, base station, transceiver, communicator, reader, etc. It is typically used for wirelessly reading (and sometimes writing) messages from a terminal. A reader can be a mobile or fixed device.

[0030] Downlink: In the context of communication between a reader and a terminal, this refers to the direction of signal flow from the reader to the terminal.

[0031] Uplink: In the context of communication between a reader and a terminal, it refers to the direction of signal flow from the terminal to the reader.

[0032] A tag, or electronic tag, is an electronic identifier attached to an object for the purpose of automatically identifying, tracking, and obtaining information about that object.

[0033] Backscattering, also known as reverse scattering or backscattering, is a communication technology in which tags controllably alter and reflect radio waves from a reader. The radio waves before and after reflection have the same frequency, and the tag itself does not generate new frequency radio waves.

[0034] In existing technologies, tags (especially sensor tags) typically begin operating after receiving downlink RF signals. The resulting uplink RF signals often operate at a single carrier frequency, making their performance susceptible to environmental factors such as strong background electromagnetic reflection and multipath effects. This results in poor demodulation accuracy and limited application scenarios. To address these issues, this application provides a dual-frequency differential read / write device and system that utilizes the dual-frequency uplink RF signals generated by the tag to obtain differential signals, thereby overcoming the aforementioned problems of single-frequency tag devices or systems.

[0035] Please see Figure 1 or Figure 3 , Figure 1 or Figure 3 This is a schematic diagram of a dual-frequency differential read / write system provided in an embodiment of this application. The system is applied in the field of communication technology. The system includes a dual-frequency tag device and a read / write device, wherein:

[0036] The read / write device includes a read / write unit and an antenna. The read / write device is configured to send downlink messages and receive uplink messages.

[0037] Specifically, the downlink message includes a downlink radio frequency signal, the carrier frequency of which depends on the operating principle of the corresponding dual-frequency tag device. For example, when the dual-frequency tag device is based on the backscattering principle, the downlink message contains at least the two carrier frequencies on which the dual-frequency tag device operates; or, when the dual-frequency tag device is based on the passive frequency conversion principle, the reader / writer can transmit only a downlink message with a single carrier frequency.

[0038] It should be understood that the read / write device in the embodiments of this application is a device equipped with a processor that can execute computer execution instructions. It can be a reader / writer device or a network device that integrates reader / writer functionality. The network device can also be an access network device or a wireless access network device, such as a base station. The base station or reader / writer device can be fixed or mobile. For example, a helicopter or drone can be configured to act as a mobile base station.

[0039] The dual-frequency tag device is configured to receive downlink messages and send uplink messages.

[0040] In one implementation, the uplink message is generated based on the downlink message. Specifically, the uplink message includes two uplink radio frequency signals, which are generated based on the downlink radio frequency signals.

[0041] In one example, the dual-frequency tag device is based on the backscattering principle. See also... Figure 1 and Figure 2 The read / write device includes a read / write unit and an antenna. The downlink messages transmitted by the read / write device include at least the two carrier frequencies f1 and f2 on which the dual-frequency tag device operates. The dual-frequency tag device is based on the surface acoustic wave (SAW) principle. The dual-frequency tag device includes an antenna, an impedance matching module, SAW resonator one, and SAW resonator two. The impedance matching module is electrically connected to the antenna, and both SAW resonator one and SAW resonator two are electrically connected to the impedance matching module. The operating frequency of SAW resonator one is f1, and the operating frequency of SAW resonator two is f2.

[0042] Since dual-frequency tag devices are based on the backscattering principle, the downlink messages entering a dual-frequency tag device must include at least the two carrier frequencies on which the dual-frequency tag device operates. Figure 1 In the context of {f1, f2}, the symbol "{}" indicates inclusion or inclusion. For example, a downlink message sent by the read / write device simultaneously includes downlink radio frequency signals at carrier frequencies f1 and f2, or a downlink message sent by the read / write device time-divisionally includes downlink radio frequency signals at carrier frequencies f1 and f2. The aforementioned "simultaneously includes" means that the two downlink radio frequency signals at different carrier frequencies are synchronized or aligned in time. The aforementioned "time-divisionally includes" means that the two downlink radio frequency signals at different carrier frequencies are sequential in time; for example, the read / write device transmits two downlink radio frequency signals at different carrier frequencies sequentially using a scanning frequency method or a frequency hopping method.

[0043] A SAW resonator comprises a piezoelectric substrate and interdigital transducers and a reflector grating fabricated on the substrate. By controlling the structural parameters of the interdigital transducer (such as grating width, grating length, and grating spacing), it can be made to operate within a specific frequency range. Simultaneously, the reflector grating is typically composed of a periodically arranged metal grating array; surface acoustic waves (SAWs) undergo mechanical reflection at the reflector grating due to discontinuities in acoustic impedance. Common reflector grating types include interdigital reflector gratings, short-circuit reflector gratings, open-circuit reflector gratings, and positive-negative reflector gratings. It is understood that by designing the characteristic parameters of the reflector grating (such as grating width, spacing between grating electrodes, grating type, and grating electrode material), the reflector grating can be made to reflect only SAWs of a specific frequency. For example, the center frequencies of SAW resonator one and SAW resonator two are 431MHz and 433MHz, respectively. Correspondingly, the downlink message transmitted by the read / write device should include at least a 431MHz downlink RF signal and a 433MHz downlink RF signal.

[0044] In another example, the dual-frequency tag device is based on the passive frequency conversion principle. See also... Figure 3 and Figure 4 The read / write device includes a read / write unit and an antenna; the downlink message transmitted by the read / write device uses a single carrier frequency, i.e., the carrier frequency is f0; the dual-frequency tag device includes an antenna, a passive mixer unit, a frequency selection unit one, and a frequency selection unit two. Port one of the passive mixer unit is electrically connected to the antenna, port two of the passive mixer unit is electrically connected to frequency selection unit one, and port three of the passive mixer unit is electrically connected to frequency selection unit two. The operating frequency of frequency selection unit one is f0. s1 The operating frequency of frequency selection unit two is f s2 .

[0045] The passive mixer unit is configured to generate a wideband radio frequency (RF) signal based on the downlink RF signal, passively mix the frequency-selected signal (obtained by frequency selection unit one) with the downlink RF signal to obtain uplink RF signal one, and passively mix the frequency-selected signal (obtained by frequency selection unit two) with the downlink RF signal to obtain uplink RF signal two; wherein the carrier frequencies of the downlink RF signal, uplink RF signal one, and uplink RF signal two are different from each other. The frequency range of the wideband RF signal covers from DC to the carrier frequency of the downlink RF signal. Uplink RF signal one and uplink RF signal two are f1 and f2, respectively.

[0046] For example, the passive mixer unit includes a transistor, preferably a high electron mobility transistor or a two-dimensional electron gas field-effect transistor, and one of the three ports of the passive mixer unit is any one of the gate, drain, or source. For example, port one is the drain, and ports two and three are any one of the gate or source; or, port one is the source, and ports two and three are any one of the gate or drain. Optionally, the transistor is a bipolar transistor, and one of the three ports of the passive mixer unit is any one of the base, collector, or emitter. For example, port one is the base, and ports two and three are any one of the collector or emitter; or, port one is the emitter, and ports two and three are any one of the base or collector. The relationship between f1 or f2 and f0 can be found in prior art, such as: Patent Document 1: CN202310112908.0 A passive frequency conversion structure and a passive frequency conversion method; or Patent Document 2: CN202411270397.6 Communication circuit, method, device and system.

[0047] Frequency selection unit one is configured to filter and select the frequency of the broadband radio frequency signal to obtain frequency selection signal one.

[0048] Frequency selection unit two is configured to filter and select the frequency of the broadband radio frequency signal to obtain frequency selection signal two.

[0049] In the two examples mentioned above, since the generation environment and propagation path of the two uplink radio frequency signals are the same or similar, one of the uplink radio frequency signals generated by the dual-frequency tag device is used as a reference. The differential signal is obtained based on the demodulated signal of the two uplink radio frequency signals. This differential signal represents the real target quantity, thereby solving the problems of poor demodulation accuracy and limited application scenarios caused by the inability to eliminate various interferences in a single uplink radio frequency signal.

[0050] The following describes possible implementations of the dual-frequency tag device of this application, using a sensor tag device as an example.

[0051] In one embodiment, the dual-frequency tag device can be used to construct an anti-interference, high-precision target parameter sensing device.

[0052] In this embodiment, the change in the target parameter causes a change in the uplink radio frequency signal carrier frequency of the dual-frequency tag device; that is, this sensing method can be regarded as a frequency modulation (FM) mode. It is understood that for FM mode, the radio frequency is affected by the radio frequency signal path (e.g., multipath effect, Doppler effect, power attenuation), environmental factors (e.g., temperature, vibration), etc. By demodulating the uplink radio frequency signal of the dual-frequency tag to obtain a differential signal, interference from non-target parameters can be canceled, thus obtaining a pure target parameter. Specifically, both SAW resonator one (or frequency selection unit one) and SAW resonator two (or frequency selection unit two) can sense changes in the target parameter, and their target parameter sensing coefficients have opposite signs. The sensing capabilities of SAW resonator one (or frequency selection unit one) and SAW resonator two (or frequency selection unit two) for non-target parameters are the same or similar.

[0053] In one example, a dual-frequency tag device is used to construct an interference-resistant, high-precision temperature sensing device. It can be understood that temperature is the target parameter, while other parameters such as strain and pressure are non-target parameters.

[0054] Please see Figure 2 In this embodiment, SAW resonators 1 and 2 are installed close to each other, so that they are affected by the same or similar external environmental influences. Both SAW resonators 1 and 2 can sense temperature changes, and their temperature coefficients have opposite signs (i.e., one is a positive temperature coefficient, and the other is a negative temperature coefficient). Other parameters of the two units (e.g., strain, air pressure, humidity, etc.) are the same or similar. Both SAW resonators 1 and 2 are single-port surface acoustic wave resonators. SAW resonator 1 includes a piezoelectric material and an interdigital transducer 1 and a reflective grating 1 fabricated on the piezoelectric material. SAW resonator 2 includes a piezoelectric material and an interdigital transducer 2 and a reflective grating 2 fabricated on the piezoelectric material. The piezoelectric material of both SAW resonators is ST-cut quartz.

[0055] It is understandable that, in the aforementioned example of a high-precision temperature sensing device, for the uplink radio frequency signal 1 (whose carrier frequency is f1), the read / write device can demodulate the nominal sensing quantity 1C according to the preset relationship between frequency and sensing quantity. total1 =C temp1 +C else1 , where C temp1 C is the temperature sensing quantity sensed by the SAW resonator. else1 Interference caused by other factors, including but not limited to multipath interference, Doppler effect, vibration, and pressure. For the uplink RF signal 2 (with carrier frequency f2), the read / write device can demodulate the nominal sensing quantity 2C according to the preset relationship between frequency and sensing quantity. total2 =C temp2 +C else2 , where Ctemp2 C is the temperature sensing quantity sensed by the SAW resonator. else2 The interference amount is caused by other factors, including but not limited to multipath interference, Doppler effect, vibration, and pressure. Since the generation and propagation environments of uplink RF signal one and uplink RF signal two are the same or similar, the interference amounts calculated from the two RF signals can be considered approximately equal, i.e., C. else1 =C else2 Furthermore, the read / write device can obtain the differential sensing quantity C by differentiating the two nominal sensing quantities. dif This eliminates common-mode interference. Wherein, C dif =C total1 -C total2 =C temp1 -C temp2 .

[0056] Since the temperature coefficients of frequency selection unit one and frequency selection unit two have opposite signs, the value of the differential sensing quantity is |C dif |=|C temp1 |+|C temp2 |, where the symbol "| * |" represents taking the absolute value of the variable "*". When the absolute values ​​of two temperature coefficients are the same or similar, the differential sensing quantity |C dif |=2|C temp1 |=2|C temp2 Therefore, compared to a single-frequency tag device (assuming the nominal sensing quantity obtained by the single-frequency tag device is C), it is clear that... total3 =C temp3 +C else3 Dual-frequency tag devices can not only eliminate environmental common-mode interference to obtain pure target sensing data, but also improve the sensitivity to target sensing data.

[0057] In this embodiment, temperature is the target parameter. It is understood that the target parameter can also be other physical quantities, such as strain, vibration, pressure, humidity, displacement, tilt angle, etc.

[0058] In another example, strain is the target parameter. A dual-frequency tag device can be used to construct an interference-resistant, high-precision strain sensing device. Based on the aforementioned temperature sensing device example, please refer to... Figure 2Both SAW resonators 1 and 2 are sensing elements based on the surface acoustic wave principle. Their installation locations are adjacent, ensuring that they sense similar or identical external environmental influences. Both resonators can sense strain changes, and their strain coefficients have opposite signs (one is positive, the other negative). Other parameters of the two resonators (such as temperature, air pressure, and humidity) are the same or similar. Therefore, this dual-frequency tag device not only eliminates environmental common-mode interference to obtain pure target sensing data but also improves the sensitivity to target sensing data.

[0059] Optionally, in other embodiments, SAW resonator one (or frequency selection unit one) is insensitive to changes in target parameters, while SAW resonator two (or frequency selection unit two) can sense changes in target parameters. The non-target parameters of SAW resonator one (or frequency selection unit one) and SAW resonator two (or frequency selection unit two) are the same or similar. With this configuration, an interference-resistant, high-precision target parameter sensing device can still be constructed.

[0060] For example, based on the aforementioned temperature sensing device example, SAW resonator pair 1 is temperature insensitive, while SAW resonator pair 2 can sense temperature changes. Other parameters of the two units (e.g., strain, air pressure, humidity, etc.) are the same or similar. In this case, for uplink RF signal 1 (whose carrier frequency is f1), the read / write device can demodulate the nominal sensed quantity 1 C according to the preset relationship between frequency and sensed quantity. total1 =C else1 For the uplink radio frequency signal 2 (whose carrier frequency is f2), the read / write device can demodulate the nominal sensing quantity 2C according to the preset relationship between frequency and sensing quantity. total2 =C temp2 +C else2 Since the generation and propagation environments of uplink RF signal one and uplink RF signal two are the same or similar, the interference quantities calculated from the two RF signals can be considered approximately equal, i.e., C. else1 =C else2 Furthermore, the read / write device can obtain the differential sensing quantity C by differentiating the two nominal sensing quantities. dif This eliminates common-mode interference. Where, |C dif |=|C temp2 Therefore, compared to a single-frequency tag device (assuming the nominal sensing quantity obtained by the single-frequency tag device is C), it is clear that... total3 =C temp3 +C else3 Dual-frequency tag devices can eliminate environmental common-mode interference to obtain pure target sensing data, thereby improving sensing accuracy.

[0061] The following section describes the receiving module in the read / write device.

[0062] Please see Figure 5 , Figure 5 Exemplary demonstration Figure 1 or Figure 2 A schematic diagram of the receiving module structure in the read / write device. In this example, the receiving module includes a duplexer, a frequency one analog processing module, a frequency two analog processing module, and a parsing module.

[0063] The duplexer separates the radio frequency signals of two frequencies. The separated frequencies, f1 and f2, are then fed into their respective analog processing modules to obtain IQ baseband signals. The analysis module obtains the corresponding nominal sensing quantity based on the IQ baseband signals of each frequency, and then performs a differential operation on the nominal sensing quantities of the two frequencies to obtain the differential sensing quantity. This differential sensing quantity can eliminate environmental common-mode interference and is a relatively pure target sensing quantity, thereby improving sensing accuracy and precision.

[0064] In this example, a zero-IF receiver architecture is adopted. The frequency one analog processing module includes amplifier one, local oscillator one, phase shifter one, mixer one, and mixer two. The RF signal of frequency one f1 and the in-phase RF signal of local oscillator one are mixed by mixer one to obtain the I-channel baseband signal of frequency one. The RF signal of frequency one f1 and the 90° phase-shifted RF signal of local oscillator one are mixed by mixer one to obtain the Q-channel baseband signal of frequency one. The frequency two analog processing module includes amplifier two, local oscillator two, phase shifter two, mixer three, and mixer four. The RF signal of frequency two f2 and the in-phase RF signal of local oscillator two are mixed by mixer three to obtain the I-channel baseband signal of frequency two. The RF signal of frequency one f2 and the 90° or quadrature phase-shifted RF signal of local oscillator one are mixed by mixer four to obtain the Q-channel baseband signal of frequency two.

[0065] The analysis module obtains the calculation results for each frequency based on the IQ baseband signals. Then, based on the calculated frequency values ​​and using a pre-saved relationship between the frequency values ​​and the nominal sensing values ​​of the target parameters, or by looking up a table, the module obtains the corresponding nominal sensing values ​​of the target parameters. Further, the analysis module performs a differential operation on the nominal sensing values ​​of the target parameters corresponding to the two frequencies to obtain the differential sensing quantity. This differential sensing quantity eliminates environmental common-mode interference and is a relatively pure target sensing quantity, thereby improving sensing accuracy and precision.

[0066] It is understood that the above only exemplifies a receiving module based on a zero-IF architecture, and the receiving module of this application can also be other non-coherent demodulation or coherent demodulation methods. The coherent demodulation method can also be based on a superheterodyne architecture or a low-IF architecture. This application does not impose any limitations on this.

[0067] Although this application has been described herein with reference to illustrative embodiments, it should be understood that many other modifications and implementations can be devised by those skilled in the art, which will fall within the scope and spirit of the principles disclosed herein. More specifically, within the scope of this application, various variations and improvements can be made to the components and / or layout of the subject matter combination layout. Besides variations and improvements to the components and / or layout, other uses will be apparent to those skilled in the art.

Claims

1. A dual-frequency differential read / write device, characterized in that, include: An electrically connected antenna and a read / write unit; the read / write unit includes a transmitting module and a receiving module; The receiving module is configured to receive uplink RF signal one and uplink RF signal two, obtain nominal sensing quantity one based on uplink RF signal one, obtain nominal sensing quantity two based on uplink RF signal two, and obtain differential sensing quantity based on nominal sensing quantity one and nominal sensing quantity two; wherein, the carrier frequency of uplink RF signal one is frequency one, and the carrier frequency of uplink RF signal two is frequency two, and frequency one and frequency two are different.

2. The apparatus according to claim 1, characterized in that, The receiving module includes a duplexer, a frequency one analog processing module, a frequency two analog processing module, and a parsing module; the frequency one analog processing module and the frequency two analog processing module are electrically connected to the duplexer, and the frequency one analog processing module and the frequency two analog processing module are electrically connected to the parsing module.

3. The apparatus according to claim 2, characterized in that, The frequency one analog processing module is used to obtain the IQ baseband signal of frequency one; the frequency two analog processing module is used to obtain the IQ baseband signal of frequency two.

4. The apparatus according to claim 3, characterized in that, The analysis module obtains the solution value of frequency one based on the IQ baseband signal of frequency one; the analysis module obtains the solution value of frequency two based on the IQ baseband signal of frequency two.

5. The apparatus according to claim 1, characterized in that, The transmitting module transmits a downlink radio frequency signal with a single carrier frequency, or transmits a downlink radio frequency signal comprising at least one frequency and a downlink radio frequency signal comprising two frequencies.

6. The apparatus according to claim 5, characterized in that, The receiving module adopts a zero-IF architecture, a superheterodyne architecture, or a low-IF architecture.

7. A dual-frequency differential read / write system, characterized in that, It includes a dual-frequency tag device and a dual-frequency differential read / write device as described in any one of claims 1-6.

8. The system according to claim 7, characterized in that, The dual-frequency tag device includes an antenna, an impedance matching module, a first SAW resonator, and a second SAW resonator. The impedance matching module is electrically connected to the antenna, and both the first and second SAW resonators are electrically connected to the impedance matching module. The first SAW resonator operates at frequency one, and the second SAW resonator operates at frequency two.

9. The system according to claim 7, characterized in that, The dual-frequency tag device includes an antenna, a passive mixer unit, a frequency selection unit one, and a frequency selection unit two. Port one of the passive mixer unit is electrically connected to the antenna, port two of the passive mixer unit is electrically connected to the frequency selection unit one, and port three of the passive mixer unit is electrically connected to the frequency selection unit two. The operating frequencies of the frequency selection unit one and the frequency selection unit two are different.

10. The system according to claim 9, characterized in that, The passive mixer unit includes transistors.

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