CN111753567A - Radio frequency reader-writer and carrier cancellation method - Google Patents
Radio frequency reader-writer and carrier cancellation method Download PDFInfo
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- CN111753567A CN111753567A CN201910239127.1A CN201910239127A CN111753567A CN 111753567 A CN111753567 A CN 111753567A CN 201910239127 A CN201910239127 A CN 201910239127A CN 111753567 A CN111753567 A CN 111753567A
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- G06—COMPUTING; CALCULATING OR COUNTING
- 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
- G06K7/10009—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation sensing by radiation using wavelengths larger than 0.1 mm, e.g. radio-waves or microwaves
- G06K7/10019—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation sensing by radiation using wavelengths larger than 0.1 mm, e.g. radio-waves or microwaves resolving collision on the communication channels between simultaneously or concurrently interrogated record carriers.
- G06K7/10069—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation sensing by radiation using wavelengths larger than 0.1 mm, e.g. radio-waves or microwaves resolving collision on the communication channels between simultaneously or concurrently interrogated record carriers. the collision being resolved in the frequency domain, e.g. by hopping from one frequency to the other
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Abstract
The application provides a radio frequency reader-writer and a vector modulation carrier cancellation method, which comprises the following steps: the control module is used for outputting a carrier cancellation control signal when detecting that carrier signal power leakage from a transmitting link of the radio frequency reader-writer exists in a receiving link of the radio frequency reader-writer; and the vector modulation carrier cancellation module is coupled with the control module, coupled with the transmission link and the receiving link, and configured to modulate the radio frequency transmission signal from the transmission link according to the carrier cancellation parameter determined by the carrier cancellation control signal to form a leakage cancellation signal when the carrier cancellation control signal is received, so as to cancel the carrier signal leaked into the receiving link. The method and the device solve the problems that due to the fact that carrier leakage is too large, the receiver saturation is caused, the noise and the sensitivity of a receiving link are influenced, the effect of reading and writing the label of the reader-writer is influenced, and the distance is influenced, and work efficiency is greatly improved by eliminating or reducing carrier power leaked into the receiving link.
Description
Technical Field
The present application relates to a non-contact automatic identification technology, and in particular, to a radio frequency reader and a vector modulation carrier cancellation method.
Background
Radio Frequency Identification (RFID) is a wireless communication technology, and is a non-contact automatic Identification technology that uses Radio Frequency signal spatial coupling to identify a target and acquire target data. The most important advantage of the RFID technology is non-contact identification, the RFID technology has the advantages that the RFID technology can penetrate through a severe environment reading label which cannot be used by bar codes such as snow, fog, ice, paint, dust and the like, and can also identify a plurality of labels simultaneously, and the label has the advantages of small size, diversified shapes, strong pollution resistance, reusability, large data memory capacity, encryption capability and the like. With the development of the RFID technology, the application fields of the RFID technology become wide, such as food safety tracing, book borrowing and returning systems, access control systems, warehouse management, parking lot management systems, traffic monitoring and management, and the like. Experts have pointed out that the RFID technology is likely to become a new technology that affects global economy and life following mobile communication technology and internet technology.
The RFID electronic tags are divided into the following parts according to different energy source obtaining modes: active, passive, semi-active semi-passive and the like. The active electronic tag is also called as an active tag, the working power supply of the tag is completely supplied by an internal battery, and meanwhile, the radio frequency energy required by the communication between the electronic tag and the reader is also supplied by the battery; the tag has the advantages of long reading/writing distance, large, thick and heavy external dimension, high cost, limited application field, no long-term use of the battery, and replacement of the battery after energy is exhausted. The semi-active electronic tag is also called a semi-active tag, and the battery only supplies power to a circuit for maintaining data in the tag; before the tag does not enter the working state, the tag is always in the dormant state, which is equivalent to a passive tag; when the tag enters a reading area of a reader, the tag is excited by a radio frequency signal sent by the reader to enter a manual operation state; the advantages and disadvantages of the tag are substantially the same as those of the active tag. The passive electronic tag is also called a passive tag, a battery is not arranged in the passive electronic tag, and the tag converts part of energy from radio frequency energy emitted by a reader into a power supply required by the operation of the tag; the label has the advantages of small and exquisite appearance, light weight, thinness, convenient installation, low cost and long service life, is suitable for various use occasions, and can be free of maintenance. In addition, the ultrahigh frequency RFID (international standard ISO18000-6C stipulates an operating frequency band of 860-960 MHz) has a shorter operating wavelength than the high frequency 13.56MHz and the low frequency 125KHz, the antenna size is small and flexible, and the application is flexible, so that the ultrahigh frequency passive tag and the reader-writer become the key direction of the development of the field of the Internet of things in recent years.
Because the passive RFID tag is powered by the radio frequency signal transmitted by the reader and sends out the information stored in the chip, the radio frequency transmitting link is required to be in a working state all the time, the isolation degree of the coupling circuit and the antenna standing wave are influenced by actual devices, so that part of carrier signal power leaks into the receiving link, the frequency of the signal scattered and returned by the tag is very close to the frequency of the carrier signal, the receiver is saturated due to excessive carrier leakage, the noise and the sensitivity of the receiving link are influenced, and the effect and the distance of the reader for reading and writing the tag are further influenced.
Content of application
In view of the foregoing disadvantages of the prior art, an object of the present application is to provide a radio frequency reader/writer and a vector modulation carrier cancellation method, which are used to solve the problems in the prior art that isolation of a coupling circuit and antenna standing waves are affected by an actual device, so that a part of carrier signals leak into a receiving link, a frequency of signals scattered and returned by a tag is very close to a frequency of the carrier signals, and excessive carrier leakage may cause saturation of a receiver, affect noise and sensitivity of the receiving link, and further affect an effect and a distance for the reader/writer to read and write the tag.
To achieve the above and other related objects, the present application provides a radio frequency reader, including: the control module is used for outputting a carrier cancellation control signal when detecting that a carrier signal leaked from a transmitting link of the radio frequency reader-writer exists in the receiving link of the radio frequency reader-writer; and the vector modulation carrier cancellation module is coupled with the control module, coupled with the transmission link and the receiving link, and configured to modulate the radio frequency transmission signal from the transmission link according to the carrier cancellation parameter determined by the carrier cancellation control signal to form a leakage cancellation signal when the carrier cancellation control signal is received, so as to cancel the carrier signal leaked into the receiving link.
In an embodiment of the present application, the vector modulation carrier cancellation module includes an attenuation unit for attenuating the radio frequency transmission signal.
In an embodiment of the present application, the vector modulation carrier cancellation module includes: the vector modulation unit is coupled with the control module; a combining unit, connected to the receiving link, for combining the rf receiving signal and the leakage cancellation signal, so as to cancel the carrier signal leaked to the receiving link to obtain a useful signal; and the amplifying unit is connected in the receiving chain, coupled to the combining unit and used for amplifying the useful signal.
In an embodiment of the present application, the vector modulation carrier cancellation module further includes: and the input end of the first detection unit is connected with the input end of the merging unit, and the output end of the first detection unit is connected with the control module, and the first detection unit is used for detecting the leaked carrier signal power and transmitting the detection result to the control module.
In an embodiment of the present application, the vector modulation carrier cancellation module further includes: and the input end of the second detection unit is coupled to the output end of the amplification unit, and the output end of the second detection unit is connected to the control module and used for detecting whether the useful signal has a leaked carrier signal or not and transmitting a detection result to the control module.
In an embodiment of the present application, the vector modulation carrier cancellation module further includes: and the digital potentiometer is coupled between the amplifying unit and the second detection unit and used for detecting the electric potential and increasing the detection dynamic range of the second detection unit.
In an embodiment of the present application, the vector modulation carrier cancellation module further includes: the signal conversion unit is coupled with the control module and used for receiving the control signal of the control module and converting the control signal into two groups of carrier cancellation control signals in the form of analog differential signals; the control module is used for determining the carrier cancellation parameters used by the vector modulation unit through a dichotomy according to the carrier cancellation control signals in the form of the two groups of analog differential signals.
In an embodiment of the present application, the rf reader further includes: the transmitting module is used for transmitting the radio frequency transmitting signal; a coupling module, coupled to the transmission module and coupled to the vector modulation carrier cancellation module, for coupling the radio frequency transmission signal; the radio frequency matching module is coupled with the coupling module and used for changing the output impedance characteristic of the coupling module; the antenna module is coupled with the radio frequency matching module; a receiving module, coupled to the vector modulation carrier cancellation module, for receiving the signal after passing through the vector modulation carrier cancellation module; wherein the coupling module is further coupled with a receiving module, and the control module is coupled with the transmitting module and the receiving module; and the transmitting link is used as the transmitting link according to the sequence of the transmission of the transmitting module, the coupling module, the radio frequency matching module and the antenna module, and the receiving link is used as the receiving link according to the sequence of the transmission of the antenna module, the radio frequency matching module and the receiving module.
To achieve the above and other related objects, the present application provides a vector modulation carrier cancellation method, comprising: when detecting that the carrier signal power leakage from the transmitting link of the radio frequency reader-writer exists in the receiving link of the radio frequency reader-writer, forming a carrier cancellation control signal; the carrier cancellation control signal comprises a carrier cancellation parameter for controlling the vector modulation carrier cancellation module to modulate the radio frequency transmission signal from the transmission link according to the carrier cancellation parameter to form a leakage cancellation signal for canceling the carrier signal leaked into the reception link.
As described above, the radio frequency reader and the vector modulation carrier cancellation method of the present application have the following beneficial effects: the problem of the isolation of coupling circuit and antenna standing wave receive the influence of actual device to make partly carrier signal power leak to receiving link, and the signal frequency that the label scattering returned is very close with carrier signal frequency, and carrier leakage is too big can lead to the receiver saturation, influences the noise and the sensitivity of receiving link, and then influences the effect and the distance of reader write label is solved, eliminate or reduce the carrier power that leaks to receiving link for work efficiency has very big improvement.
Drawings
Fig. 1 is a structural diagram of an rf reader in an embodiment of the present application.
Fig. 2 is a structural diagram of an rf reader in an embodiment of the present application.
Fig. 3 is a flowchart illustrating a vector modulation carrier cancellation method according to an embodiment of the present application.
Description of the element reference numerals
10 radio frequency reader-writer
11 transmitting module
12 coupling module
13 radio frequency matching module
14 antenna module
15 control module
16 vector modulation carrier cancellation module
161 attenuation unit
162 vector modulation unit
163 merging unit
164 amplifying unit
17 receiving module
20 radio frequency reader-writer
21 transmitting module
22 coupling module
23 radio frequency matching module
24 antenna module
25 control module
26 vector modulation carrier cancellation module
261 attenuation unit
262 vector modulation unit
263 merging unit
264 amplification unit
265 first detection unit
266 second detector unit
267 digital potentiometer
27 receiving module
Method step S1
Detailed Description
The following description of the embodiments of the present application is provided by way of specific examples, and other advantages and effects of the present application will be readily apparent to those skilled in the art from the disclosure herein. The present application is capable of other and different embodiments and its several details are capable of modifications and/or changes in various respects, all without departing from the spirit of the present application. It is to be noted that the features in the following embodiments and examples may be combined with each other without conflict.
It is noted that in the following description, reference is made to the accompanying drawings which illustrate several embodiments of the present application. It is to be understood that other embodiments may be utilized and that mechanical, structural, electrical, and operational changes may be made without departing from the spirit and scope of the present application. The following detailed description is not to be taken in a limiting sense, and the scope of embodiments of the present application is defined only by the claims of the issued patent. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. Spatially relative terms, such as "upper," "lower," "left," "right," "lower," "below," "lower," "over," "upper," and the like, may be used herein to facilitate describing one element or feature's relationship to another element or feature as illustrated in the figures.
Also, as used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context indicates otherwise. It will be further understood that the terms "comprises," "comprising," and/or "comprising," when used in this specification, specify the presence of stated features, operations, elements, components, items, species, and/or groups, but do not preclude the presence, or addition of one or more other features, operations, elements, components, items, species, and/or groups thereof. The terms "or" and/or "as used herein are to be construed as inclusive or meaning any one or any combination. Thus, "A, B or C" or "A, B and/or C" means "any of the following: a; b; c; a and B; a and C; b and C; A. b and C ". An exception to this definition will occur only when a combination of elements, functions or operations are inherently mutually exclusive in some way.
The passive RFID tag is powered by a radio frequency signal transmitted by a reader and transmits information stored in a chip, so that a radio frequency transmitting link is required to be in a working state all the time, the isolation degree of a coupling circuit and antenna standing waves are influenced by an actual device to enable a part of carrier signal power to leak into a receiving link, the frequency of a signal scattered and returned by the tag is very close to the frequency of the carrier signal, the receiver is saturated due to excessive carrier leakage, the noise and the sensitivity of the receiving link are influenced, and the effect and the distance of the reader for reading and writing the tag are further influenced.
Therefore, the radio frequency reader-writer is used for eliminating or reducing carrier power leaked into a receiving link.
The radio frequency reader-writer can read the radio frequency label and can erase and write data. The target object is automatically identified and the related data is obtained through the radio frequency identification signal, manual intervention is not needed, high-speed moving objects can be identified, a plurality of RFID labels can be identified at the same time, and the operation is quick and convenient. The RFID reader-writer is of a fixed type and a handheld type, and the handheld RFID reader-writer comprises a low frequency, a high frequency, an ultrahigh frequency, an active type and the like. For example, the contact type reader-writer can be divided into a contact type reader-writer and a non-contact type reader-writer; the slave interface can be divided into a USB reader-writer, a PCMCIA card reader-writer, an IEEE 1394 reader-writer and the like; the frequency can be divided into a low-frequency reader, a high-frequency reader, an ultrahigh-frequency reader, a dual-frequency reader, a 433MHz active reader, a microwave active reader and the like.
As shown in fig. 1, a structure diagram of a radio frequency reader/writer 10 in the embodiment of the present application is shown.
The radio frequency reader-writer 10 comprises a control module 15 and a vector modulation cancellation module 16, when a transmission link leaks carrier signals, the control module 15 can detect that the carrier signals leaked from the transmission link exist in a receiving link of the radio frequency reader-writer 10, and then output corresponding carrier cancellation control signals; the vector modulation carrier cancellation module 16 is coupled to the control module 15 and coupled to the transmission link and the reception link, when the control module 15 detects that a carrier signal leaked from the transmission link exists in the reception link of the radio frequency reader/writer 10, the control module outputs a corresponding carrier cancellation control signal, when the vector modulation carrier cancellation module 16 receives the carrier cancellation control signal, the vector modulation carrier cancellation module can determine a carrier cancellation parameter of the radio frequency transmission signal from the transmission link according to the carrier cancellation control signal, and perform corresponding modulation according to the carrier cancellation parameter to form a corresponding leakage cancellation signal, where the leakage cancellation signal is used to cancel the carrier signal leaked into the reception link. Specifically, the carrier cancellation parameter may include parameters such as signal amplitude and phase.
It should be noted that the vector modulation carrier cancellation module 16 is coupled to the control module 15 and coupled to the transmission link and the reception link, and the coupling mentioned herein may include a direct connection and an indirect connection, which is not limited in this application.
Optionally, referring to fig. 1, the vector modulation carrier cancellation module 16 includes an attenuation unit 161, where the attenuation unit 161 is configured to attenuate the radio frequency transmission signal. Specifically, when the attenuation unit 161 receives the radio frequency transmission signal, the radio frequency transmission signal is attenuated, wherein a parameter of the attenuated radio frequency transmission signal may be within a certain range. Wherein one of the parameters may be a signal amplitude. For example, the range of the radio frequency transmission signal amplitude within a certain range for the output signals of other units of the vector modulation carrier cancellation module becomes larger.
Optionally, the vector modulation carrier cancellation module 16 includes a vector modulation unit 162, the vector modulation unit 162 is coupled to the control module 15, the vector modulation unit receives a carrier cancellation control signal from the control module 15 to determine the carrier cancellation parameter used by the vector modulation unit 162, and outputs the leakage cancellation signal by modulating the carrier cancellation parameter, wherein the leakage cancellation signal is used for canceling the carrier signal leaked into the receiving link. It should be noted that the vector modulation unit 162 is coupled to the control module 15, and the coupling mentioned herein may include a direct connection and an indirect connection, which is not limited in this application. The leakage cancellation signal needs to be modulated by the carrier cancellation parameters, which may include parameters such as signal amplitude and phase.
Preferably, in this embodiment, the vector modulation unit 162 modulates the signal amplitude of the output leakage cancellation signal to be equal to or close to the amplitude of the carrier signal leaked into the receiving link through the control of the carrier cancellation control signal of the control module 15, for example, the phase of the output leakage cancellation signal is close to 180 ° different from the phase of the carrier signal leaked into the receiving link.
The vector modulation carrier cancellation module 16 includes a combining unit 163 connected in the receiving link, and configured to combine the radio frequency receiving signal with the leakage cancellation signal, so as to cancel the carrier signal leaked into the receiving link to obtain a useful signal; specifically, the combining unit 163 is coupled to the vector modulation unit 162 and connected to the receiving chain, and the combining unit 163 receives a radio frequency receiving signal of the receiving chain, where the radio frequency receiving signal includes a carrier signal leaked into the receiving chain, and combines the radio frequency receiving signal with a leakage cancellation signal output from the vector modulation unit 162, so as to cancel the carrier signal leaked into the receiving chain, and then outputs a useful signal. It should be noted that the connection and coupling herein may include a direct connection and an indirect connection, which is not limited in this application.
The vector modulation carrier cancellation module 16 includes an amplifying unit 164 connected to the receiving chain and coupled to the combining unit 163, the combining unit 163 combines the radio frequency receiving signal and the leakage cancellation signal, and after the carrier signal leaked to the receiving chain is cancelled, a useful signal is obtained for amplifying the useful signal, and the amplifying unit 164 amplifies the useful signal. It should be noted that the coupling herein may include a direct connection, an indirect connection, and the like, which is not limited in this application.
In order to achieve better cancellation and reduction of carrier signal leakage in the transmission link, as shown in fig. 2, a vector modulation carrier cancellation module in an embodiment is provided; the attenuating unit 261 may be used to implement the attenuating unit 161 in the embodiment of fig. 1, for example, the vector modulating unit 262 may be used to implement the vector modulating unit 162 in the embodiment of fig. 1, for example, the combining unit 263 may be used to implement the combining unit 163 in the embodiment of fig. 1, for example, and the combining unit 264 may be used to implement the combining unit 164 in the embodiment of fig. 1, for example.
Optionally, the vector modulation carrier cancellation module 26 further includes: a first detecting unit 265, an input end of the first detecting unit 265 is coupled to an input end of the combining unit 263, and an output end of the first detecting unit 265 is coupled to the control module 25, for detecting a carrier signal leakage condition and transmitting a detection result to the control module 25. Specifically, the detecting the carrier signal leakage condition may be detecting a magnitude of a power value leaked into the receive chain. It should be noted that the coupling mentioned herein may include a direct connection and an indirect connection, which is not limited in this application. Preferably, the first detecting unit 265 may be a detecting circuit, which detects the amount of rf power leaking into the receiving link and transmits the detected result to the control module 25.
Optionally, the vector modulation carrier cancellation module 26 further includes: a second detecting unit 266, an input end of the second detecting unit 266 is coupled to the output end of the amplifying unit 264, and an output end of the second detecting unit 266 is coupled to the control module 25, for detecting whether the useful signal has a carrier signal leakage condition, and transmitting the detection result to the control module 25. Specifically, whether the carrier signal leakage condition exists in the useful signal can be judged by detecting the magnitude of the power value of the useful signal. The control module 266 can determine whether the output carrier cancellation control signal needs to be adjusted according to the detection result. It should be noted that the coupling mentioned herein may include a direct connection and an indirect connection, which is not limited in this application. Preferably, the second detector 266 may be a detector circuit, which detects the power of the useful signal, determines whether there is carrier signal leakage according to the useful signal, and transmits the detection result to the control module 25.
Optionally, the vector modulation carrier cancellation module 26 further includes: a digital potentiometer 267 coupled between the amplifying unit 264 and the second detecting unit 266 for detecting a voltage. Specifically, the useful signal passing through the amplifying unit 264 passes through the digital potentiometer 267, and the digital potentiometer 267 can detect the potential, thereby increasing the detection dynamic range of the second detection unit 266. It should be noted that the coupling mentioned herein may include a direct connection and an indirect connection, which is not limited in this application.
Optionally, the vector modulation carrier cancellation module 26 further includes: the signal conversion unit 264 is coupled to the control module 25, and configured to receive the control signal of the control module 25 and convert the control signal into two sets of carrier cancellation control signals in the form of analog differential signals.
Optionally, the control module 25 is configured to determine the carrier cancellation parameter used by the vector modulation unit through a binary method according to the carrier cancellation control signals in the form of the two groups of analog differential signals. Specifically, the carrier cancellation parameters include parameters such as amplitude and phase.
The two sets of analog differential signals are two sets of signals with the same amplitude and opposite phases, and the control module 25 determines the optimum region of the amplitude value and the phase used by the vector modulation unit 262 according to the carrier cancellation control signal in the form of the two sets of analog differential signals by the dichotomy. The dichotomy is to first determine the middle position of the interval and then compare the looked-up value to the middle value. If the two are equal, the position is returned after the search is successful; otherwise, determining a new search area and continuing binary search. And comparing each search with the intermediate value, determining whether the search is successful, and reducing the current search interval which is unsuccessful by half to perform recursive search.
As shown in fig. 1, the radio frequency reader/writer 10 includes: a transmitting module 11, configured to transmit the radio frequency transmitting signal; a coupling module 12 coupled to the transmission module 11 and to the vector modulation carrier cancellation module 16 for coupling the radio frequency transmission signal; a radio frequency matching module 13, coupled to the coupling module 12, for changing the output impedance characteristic of the coupling module 12; an antenna module 14 coupled to the rf matching module 13; a receiving module 17, coupled to the vector modulation carrier cancellation module 16, configured to receive the signal after passing through the vector modulation carrier cancellation module 16; wherein the coupling module 12 is further coupled with a receiving module 17, and the control module 15 is coupled with the transmitting module 11 and the receiving module 17; the transmitting link is established according to the sequence of the signals sequentially transmitted by the transmitting module 11, the coupling module 12, the radio frequency matching module 13 and the antenna module 14, and the receiving link is established according to the sequence of the signals sequentially transmitted by the antenna module 14, the radio frequency matching module 13 and the receiving module 17.
Specifically, the transmitting module 11 transmits the radio frequency transmitting signal, and after the radio frequency transmitting signal passes through the coupling module 12, the vector modulation carrier cancellation module 16 receives the radio frequency transmitting signal from the coupling module 12 and the carrier cancellation control signal from the control module 15 to form the leakage cancellation signal, which cancels the leakage cancellation signal with the carrier signal leaked to the receiving link.
The transmit module 11 may include a voltage controlled oscillator coupled to a power amplifier, the voltage oscillator being used to control the frequency and the power amplifier being used to produce a maximum power output. The antenna module 14 may include a switch coupled to the antennas, and the switch may control a selected one of the antennas to radiate a radio signal. The receiving module 17 may include: the filter is coupled to the mixer and the amplifier to obtain a better signal to be transmitted to the control module 15.
It should be noted that the coupling mentioned herein may include a direct connection and an indirect connection, which is not limited in this application.
Optionally, the radio frequency matching module 13 includes a radio frequency matching circuit; the radio frequency matching circuit comprises at least one group of L-shaped matching networks, the radio frequency matching circuit comprising the L-shaped matching networks has the characteristic of changing the output impedance of the coupling module, the isolation degree of the coupling module is increased, the effect of reducing carrier power leaked into the receiving circuit is achieved, and the main path power is hardly influenced.
Similar to the principle of the foregoing radio frequency reader/writer embodiment, in this embodiment, a vector modulation carrier cancellation method may also be provided, where the method includes: when detecting that a carrier signal leaked from a transmitting link of the radio frequency reader-writer exists in a receiving link of the radio frequency reader-writer, forming a carrier cancellation control signal; the carrier cancellation control signal comprises a carrier cancellation parameter for controlling the vector modulation carrier cancellation module to modulate the radio frequency transmission signal from the transmission link according to the carrier cancellation parameter to form a leakage cancellation signal for canceling the carrier signal leaked into the reception link.
The following description refers to specific embodiments: as shown in fig. 3, the present application provides a vector modulation carrier cancellation method. The method may be applied, for example, in the embodiments of fig. 1 or fig. 2. Alternatively, the method may be implemented by running a computer program loaded on the control module.
The method comprises the following steps:
step S301: detecting whether a carrier signal leaked from a transmitting link of the radio frequency reader-writer exists in a receiving link of the radio frequency reader-writer;
step S302: if yes, forming a carrier wave cancellation control signal;
step S303: if not, no carrier cancellation control signal is formed.
The carrier cancellation control signal comprises a carrier cancellation parameter for controlling the vector modulation carrier cancellation module to modulate the radio frequency transmission signal from the transmission link according to the carrier cancellation parameter to form a leakage cancellation signal for canceling the carrier signal leaked into the reception link. Specifically, the vector modulation carrier cancellation module is coupled to the transmission link and the reception link, and outputs a corresponding carrier cancellation control signal when detecting that a carrier signal leaked from the transmission link exists in the reception link, and when receiving the carrier cancellation control signal, the vector modulation carrier cancellation module may determine a carrier cancellation parameter of the radio frequency transmission signal from the transmission link according to the carrier cancellation control signal, and perform corresponding modulation according to the carrier cancellation parameter to form a corresponding leakage cancellation signal, where the leakage cancellation signal is used to cancel the carrier signal leaked to the reception link. Specifically, the carrier cancellation parameter may include parameters such as signal amplitude and phase. It should be noted that the coupling mentioned herein may include a direct connection and an indirect connection, which is not limited in this application.
To sum up, the problem that due to the fact that carrier leakage is too large, the receiver is saturated, noise and sensitivity of a receiving link are affected, and then the effect and the distance of a reader-writer for reading and writing the label are affected is solved. Therefore, the application effectively overcomes various defects in the prior art and has high industrial utilization value.
The above embodiments are merely illustrative of the principles and utilities of the present application and are not intended to limit the application. Any person skilled in the art can modify or change the above-described embodiments without departing from the spirit and scope of the present application. Accordingly, it is intended that all equivalent modifications or changes which can be made by those skilled in the art without departing from the spirit and technical concepts disclosed in the present application shall be covered by the claims of the present application.
Claims (10)
1. A radio frequency reader, comprising:
the control module is used for outputting a carrier cancellation control signal when detecting that carrier signal power leakage from a transmitting link of the radio frequency reader-writer exists in a receiving link of the radio frequency reader-writer;
and the vector modulation carrier cancellation module is coupled with the control module, coupled with the transmission link and the receiving link, and configured to modulate the radio frequency transmission signal from the transmission link according to the carrier cancellation parameter determined by the carrier cancellation control signal to form a leakage cancellation signal when the carrier cancellation control signal is received, so as to cancel the carrier signal leaked into the receiving link.
2. The radio frequency reader of claim 1, wherein the vector modulation carrier cancellation module comprises an attenuation unit to attenuate the radio frequency transmit signal.
3. The radio frequency reader of claim 1, wherein the vector modulation carrier cancellation module comprises:
the vector modulation unit is coupled with the control module;
a combining unit, connected to the receiving link, for combining the leaked carrier signal with the cancellation signal, so as to cancel the carrier signal leaked to the receiving link to obtain a useful signal;
and the amplifying unit is connected in the receiving link, coupled to the combining unit, and used for amplifying the useful tag signal.
4. The radio frequency reader of claim 3, wherein the vector modulation carrier cancellation module further comprises:
and the input end of the first detection unit is connected with the input end of the merging unit, and the output end of the first detection unit is connected with the control module, and is used for detecting the carrier signal leakage power and transmitting the detection result to the control module.
5. The radio frequency reader of claim 3, wherein the vector modulation carrier cancellation module further comprises:
and the input end of the second detection unit is coupled to the output end of the amplification unit, and the output end of the second detection unit is connected to the control module and used for detecting whether the useful signal has a leaked carrier signal or not and transmitting a detection result to the control module.
6. The radio frequency reader of claim 5, wherein the vector modulation carrier cancellation module further comprises:
and the digital potentiometer is coupled between the amplifying unit and the second detection unit and used for detecting the electric potential and increasing the detection dynamic range of the second detection unit.
7. The radio frequency reader of claim 3, wherein the vector modulation carrier cancellation module further comprises:
the signal conversion unit is coupled with the control module and used for receiving the control signal of the control module and converting the control signal into two groups of carrier cancellation control signals in the form of analog differential signals; the control module is used for determining the carrier cancellation parameters used by the vector modulation unit through a dichotomy according to the carrier cancellation control signals in the form of the two groups of analog differential signals.
8. The radio frequency reader/writer according to claim 1, further comprising:
the transmitting module is used for transmitting the radio frequency transmitting signal;
a coupling module, coupled to the transmission module and coupled to the vector modulation carrier cancellation module, for coupling the radio frequency transmission signal;
the radio frequency matching module is coupled with the coupling module and used for changing the output impedance characteristic of the coupling module;
the antenna module is coupled with the radio frequency matching module;
a receiving module, coupled to the vector modulation carrier cancellation module, for receiving the signal after passing through the vector modulation carrier cancellation module;
wherein the coupling module is further coupled with a receiving module, and the control module is coupled with the transmitting module and the receiving module; and the transmitting link is used as the transmitting link according to the sequence of the transmission of the transmitting module, the coupling module, the radio frequency matching module and the antenna module, and the receiving link is used as the receiving link according to the sequence of the transmission of the antenna module, the radio frequency matching module and the receiving module.
9. The radio frequency reader of claim 8, wherein the radio frequency matching module includes a radio frequency matching circuit; the radio frequency matching circuit comprises at least one group of L-shaped matching networks.
10. A vector modulation carrier cancellation method, comprising:
when detecting that a carrier signal leaked from a transmitting link of the radio frequency reader-writer exists in a receiving link of the radio frequency reader-writer, forming a carrier cancellation control signal;
the carrier cancellation control signal comprises a carrier cancellation parameter for controlling the vector modulation carrier cancellation module to modulate the radio frequency transmission signal from the transmission link according to the carrier cancellation parameter to form a leakage cancellation signal for canceling the carrier signal leaked into the reception link.
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