CN112149436A - Portable RFID field tester - Google Patents

Abstract

The application discloses a portable RFID field tester, which comprises a control terminal, a reader and an antenna; the control terminal is a computer or an embedded mainboard containing application software and controls the work among all the components of the tester; the reader is a device for reading label information and comprises a control unit and a radio frequency module; the radio frequency module comprises a transmitter and a receiver, the transmitter is used for sending a radio signal to the tag, and the receiver is used for receiving the radio signal of the tag; the antenna is a transmitting and receiving device for transmitting data between the tag and the reader; the control terminal controls the reader to send electromagnetic waves through the antenna, after the tag enters the electromagnetic wave magnetic field, a coil in the tag can generate induction current, and the tag starts to work and receives radio frequency signals sent by the reader; if the tag is an active tag, a radio frequency signal with a certain frequency is actively sent, and the reader acquires the signal through the antenna, decodes the signal and sends the decoded signal to a control unit of the reader for relevant data processing.

Description

A portable RFID field tester

technical field

The invention belongs to the technical field of electronic measurement, and relates to a portable RFID field tester.

Background technique

In radio communication technology, RFID technology, that is, radio frequency identification technology, is a non-visual, non-mechanical or optical contact two-way communication automatic identification technology. It has high sensitivity, high speed, strong anti-interference ability, rich information, encryption and long life. And other advantages, so that it is widely used in tag identification, reader, RFID product testing and performance evaluation.

The research of RFID technology is of great significance. It is similar to the working mechanism of radar. Radar determines the position, shape, state and other characteristics of objects by processing the radio waves or microwaves reflected by the object. RFID is also the same. As early as World War II, the military began to use it, and it has developed rapidly since the 1990s. So far, various RFID products have come one after another. With the rapid development of the RFID industry today, the quality requirements for RFID products are more stringent. Therefore, RFID detectors that detect the performance of RFID products emerge as the times require. However, RFID detection faces many difficulties, such as many standards, high performance requirements, and the bulky large-scale detection system equipment is too inconvenient. Therefore, the design and implementation of portable RFID detectors have become very necessary, and the design of related RFID electronic tags and readers has also become diversified.

SUMMARY OF THE INVENTION

In order to solve the deficiencies in the prior art, the present application provides a portable RFID field tester, which can transmit, collect and record RFID standard radio frequency signals in ultra-high frequency and microwave frequency bands, and perform radio frequency parameters, Analysis of protocol parameters and signaling data. It has the characteristics of ingenious design, convenient operation and high measurement accuracy, and has a good application prospect.

In order to achieve the above goals, the application adopts the following technical solutions:

A portable RFID field tester, the tester is used in conjunction with an RFID tag, the tag is the identification object of the RFID field tester, is composed of a coupling element and a radio frequency chip, stores user information, and is installed on the identified object. The surface of the tester includes a control terminal, a reader and an antenna;

The control terminal is a computer or an embedded motherboard containing application software, and controls the work between the various components of the tester;

The reader is a device for reading tag information, including a control unit and a radio frequency module; the radio frequency module includes a transmitter and a receiver, the transmitter is used to send radio signals to the tag, and the receiver is used to receive the radio frequency of the tag. Signal;

The antenna is a transmitting and receiving device for transmitting data between the tag and the reader;

The control terminal controls the reader to send electromagnetic waves through the antenna. After the tag enters the electromagnetic wave magnetic field, the inner coil will generate an induced current, and the tag starts to work and receives the radio frequency signal sent by the reader; if it is a passive tag, it will send out The product information stored in the chip; if it is an active tag, it will actively send a radio frequency signal of a certain frequency, and the reader obtains the signal through the antenna, decodes it and sends it to the control unit of the reader for related data processing, and finally feeds back to the control terminal to realize data interaction.

The present invention further includes the following preferred solutions:

Preferably, the control terminal of the tester and the control unit of the reader are assembled on a motherboard with a programmable embedded dual-core processor as the central chip, and the programmable embedded dual-core processor is peripherally connected with a power management module, buttons A functional module, a capacitive touch module, an asynchronous transceiver module and a radio frequency unit of a reader; the radio frequency unit is an RF agile transceiver;

The button function module and the capacitive touch module are used to realize data interaction with the user;

The asynchronous transceiver is used to realize the communication interface function of the detector;

The power management module is used to realize external and internal power supply mode conversion.

Preferably, the tester is used for signal monitoring and performance evaluation of readers and tags during RFID deployment;

The signal monitoring in the RFID deployment process includes the detection of the RFID deployment environment, the analysis of the RFID radio frequency communication signaling, and the performance evaluation based on the reference tag;

The performance evaluation of the reader and tag is divided into tag compliance detection and reader compliance detection.

Preferably, the operation process of detecting the RFID deployment environment is: during the RFID deployment process, place the portable RFID field tester and its antenna in the RFID deployment environment, and use the tester to record the signal strength of each channel; according to the set frequency The latest spectrum scan data is displayed in real time within the real-time spectrum analysis bandwidth, enabling assessment of the on-site environment.

Preferably, the analysis and operation process of the RFID radio frequency communication signaling is: when the RFID under test is in a working state, place the portable RFID field tester and its antenna within the working range of the RFID under test, and use the tester to analyze and read The communication between the device and the tag is recorded, the signaling and timing parameters in the working process are recorded, and the signaling analysis function of the RFID radio frequency communication is realized through the analysis of the signaling and timing parameters.

Preferably, the performance evaluation operation process based on the reference tag is: when the RFID under test is not in a working state, place the portable RFID field tester and supporting equipment within the working range of the RFID under test, and the supporting equipment Including detection antenna, reference label kit;

The reference tag communicates with the reader under test, and the tester is used to collect the RF signal of the product under test for analysis in the time domain and frequency domain, and obtain the main parameters of the RF performance, including the operating frequency, in-band power, read distance and write distance;

When the RFID under test is in an abnormal working state, the reference tag can also be used to replace the failed product with reduced radio frequency performance parameters for verification, and the system fault can be assisted in locating and diagnosing.

Preferably,

The label compliance detection process is as follows:

Collect and analyze the returned response signal by sending the command signal to the tested tag;

Perform modulation depth, pulse width, under- or over-modulation, and frequency domain analysis of the returned response signal;

The modulation depth refers to the ratio of the amplitude of the modulated wave to the amplitude of the carrier;

The pulse width is the period during which the pulse can reach the amplitude;

The under-modulation refers to the ratio of the time when the peak value of the modulated signal peak is lower than the normal modulation amplitude to the pulse width time;

The overmodulation refers to the ratio of the time to pulse width when some peaks of the modulated signal exceed the normal modulation amplitude;

The frequency domain analysis includes analyzing the center frequency, frequency drift, adjacent channel leakage ratio and phase of the measured signal;

The center frequency is the theoretical center frequency of the signal under test, represented by f _o ;

Frequency _{drift refers} to the situation that the output _frequency value of the radio frequency equipment changes in one direction with time when it works continuously for a long time. Expressed as:

f _Δ = f _mea - f _o

The adjacent channel leakage ratio is used to measure the influence characteristics of the radio frequency equipment on the channel outside the main operating frequency. :

The reader compliance detection includes time domain signal analysis and reader detection frequency analysis on the signal sent by the reader;

The time-domain signal analysis displays the time-domain waveform of the measured signal after frequency conversion and various parameters analyzed based on the time-domain waveform;

The reader detection frequency analysis includes the center frequency, frequency drift, adjacent channel leakage ratio and phase analysis of the measured signal.

The beneficial effects achieved by this application:

Through the targeted design of the RFID field tester, this application realizes an integrated, small-sized and portable RFID field tester, which can perform performance tests on the tags and readers at the installation points of the tags, and realizes the performance test of the RFID related equipment. Real-time and reliable detection enables RFID products to obtain better performance, more reliable product protection, and more user-friendly technical support.

Description of drawings

1 is a schematic diagram of the system architecture of a portable RFID field tester of the application;

2 is a schematic diagram of the hardware architecture of a portable RFID field tester of the application;

FIG. 3 is a schematic diagram of a compliance testing software architecture of a portable RFID field tester of the present application.

Detailed ways

The present application will be further described below with reference to the accompanying drawings. The following examples are only used to more clearly illustrate the technical solutions of the present invention, and cannot be used to limit the protection scope of the present application.

As shown in FIG. 1 , a portable RFID field tester of the present application, the tester is used in conjunction with an RFID tag, and the tag is the identification object of the RFID field tester, which is composed of a coupling element and a radio frequency chip. With user information, it is installed on the surface of the identified object, and the tester includes a control terminal, a reader and an antenna;

The control terminal is a computer or an embedded motherboard containing application software, and controls the work between the various components of the tester;

The reader is a device for reading tag information, including a control unit and a radio frequency module; the radio frequency module includes a transmitter and a receiver, the transmitter is used to send radio signals to the tag, and the receiver is used to receive the radio frequency of the tag. Signal;

The antenna is a transmitting and receiving device for data transmission between the tag and the reader; in practical applications, the system power, the shape and relative position of the antenna will affect the data transmission and reception performance of the reader;

The control terminal controls the reader to send electromagnetic waves through the antenna. After the tag enters the electromagnetic wave magnetic field, the inner coil will generate an induced current, and the tag starts to work and receives the radio frequency signal sent by the reader; if it is a passive tag, it will send out The product information stored in the chip; if it is an active tag, it will actively send a radio frequency signal of a certain frequency, and the reader obtains the signal through the antenna, decodes it and sends it to the control unit of the reader for related data processing, and finally feeds back to the control terminal to realize data interaction.

As shown in FIG. 2 , in the specific embodiment of the present application, the control terminal of the tester and the control unit of the reader are assembled on a motherboard with a programmable embedded dual-core processor as the central chip, and the programmable embedded dual-core processor The Xilinx ZYNQ SOC is selected in the actual implementation of the processor, and the programmable embedded dual-core processor is peripherally connected with a power management module, a key function module, a capacitive touch module, an asynchronous transceiver module and a radio frequency unit of a reader; the radio frequency unit It is an RF agile transceiver, and AD9361 is used in the RF agile transceiver in actual implementation;

The button function module and the capacitive touch module are used to realize data interaction with the user;

The asynchronous transceiver is used to realize the communication interface function of the detector;

The power management module is used to realize external and internal power supply mode conversion.

When specifically implemented, the tester is used for signal monitoring and performance evaluation of readers and tags during RFID deployment;

The signal monitoring in the RFID deployment process includes the detection of the RFID deployment environment, the analysis of the RFID radio frequency communication signaling, and the performance evaluation based on the reference tag;

As shown in FIG. 3 , the performance evaluation of the reader and the tag is divided into tag compliance detection and reader compliance detection.

In the specific embodiment of the present application, the operation process of detecting the RFID deployment environment is: during the RFID deployment process, place the portable RFID field tester and its antenna in the RFID deployment environment, and use the tester to record the signal strength of each channel; According to the set frequency, the latest spectrum scan data is displayed in real time within the real-time spectrum analysis bandwidth, so as to realize the assessment of the on-site environment. In addition, for the signal interference problem in the complex RF environment, the RF communication process signal can be captured, big data can be collected over a long period of time, and an interference event of unknown duration that occurs at an unknown time and unknown location can be obtained.

In the specific embodiment of the present application, the analysis and operation process of the RFID radio frequency communication signaling is as follows: when the RFID under test is in a working state, place the portable RFID field tester and its antenna within the working range of the RFID under test, and use The tester analyzes the communication between the reader and the tag, records the signaling and timing parameters in the working process, and realizes the function of RFID RF communication signaling analysis through the analysis of the signaling and timing parameters. The signaling analysis function is mainly aimed at the detection, verification and analysis of the communication signaling between the reader and the tag. It can analyze the signaling sending and receiving sequence, and perform tracking and detection, so as to visually observe the communication timing between the reader and the tag, and analyze the existence of The signaling point of the problem. When the RFID under test is in an abnormal working state, the specific situation of the abnormal phenomenon can be further analyzed, and the cause of the abnormality can be traced back. In the RFID RF communication signaling mode configuration, the detector works in different detection modes such as reader simulation, tag simulation, and signal monitoring. Among them, the reader mode can actively transmit the command signal, and simultaneously receive and analyze the tag response signal, which is suitable for electronic label detection; the tag mode can receive and analyze the command signal, and simultaneously transmit the response signal, which is suitable for the compliance and performance testing of the reader; The signal monitoring mode can collect, stream and playback RFID communication signals in real time, which is suitable for the overall performance detection and fault diagnosis of RFID.

In the specific embodiment of the present application, the performance evaluation operation process based on the reference tag is: when the RFID under test is not in a working state, place the portable RFID field tester and supporting equipment within the working range of the RFID under test, The supporting equipment includes a detection antenna and a reference label kit;

As shown in Figure 3, the reference tag communicates with the reader under test, and the tester is used to collect the RF signal of the product under test to analyze the time domain and frequency domain, and obtain the main parameters of the RF performance. The main parameters include the working frequency, in-band power, read distance and write distance;

When the RFID under test is in an abnormal working state, the reference tag can also be used to replace the failed product with reduced radio frequency performance parameters for verification, and the system fault can be assisted in locating and diagnosing.

In the specific embodiment of the present application, the label compliance detection process is: by sending an instruction signal to the tested label, collecting and analyzing the returned response signal;

Including modulation depth, pulse width, under- or over-modulation, and frequency domain analysis of the returned response signal;

The modulation depth refers to the ratio of the amplitude of the modulated wave to the carrier amplitude, expressed as a percentage R _md ;

If the modulation function p(t) of the signal is known:

p(t)=(A+m(t))×cos 2πft

In the formula: A is the carrier amplitude; m(t) is the modulated waveform function; f is the frequency; t is the time.

Then the modulation depth R _md can be expressed as:

Where: peak(m) is the peak value of the modulated waveform function;

The modulation depth R _md can also be expressed by the amplitude relationship between the modulated wave and the carrier:

Where: m _max is the maximum amplitude of the modulated wave; m _min is the minimum amplitude of the modulated wave; p _max is the maximum amplitude of the carrier; p _min is the minimum amplitude of the carrier;

The pulse width represents the period during which the pulse can reach the amplitude, which is represented by T, namely:

T=t _um +t _om +t _am

In the formula: t _um is the under-modulation time; t _om is the over-modulation time; t _am the time of normal modulation amplitude;

The under-modulation refers to the ratio of the time t _{um when the peak value of the modulated signal peak is lower than the normal modulation amplitude to the pulse width time T, and the ratio of the time t um of} the normal modulation amplitude to the pulse width time T is expressed as:

The overmodulation uses the ratio of the time t om of the modulation signal to the pulse width T and the time t _om of the normal modulation amplitude, and the ratio of the time t _om of the normal modulation amplitude to the pulse width T is expressed as:

The frequency domain analysis includes the center frequency, frequency drift, adjacent channel leakage ratio and phase of the measured signal;

The center frequency is the theoretical center frequency, represented by _fo ;

Frequency drift refers to the situation in which the output frequency value of the radio frequency equipment changes in one direction with time when it works continuously for a long time. The frequency drift f _Δ is expressed as the difference between the actual detection value f _mea of the measured signal center frequency and the theoretical center frequency f _o :

f _Δ = f _mea - f _o

The adjacent channel leakage ratio is used to measure the influence characteristics of the radio frequency equipment on the channel outside the main operating frequency. :

The software designs a communication data module, including decoding data, and displaying the results of RF signal decoding and identification. It can analyze the relevant measurement value, coding, preamble check, cyclic redundancy check, etc. of the reverse link frequency of the signal under test, and realize the compliance detection of various indicators of the RFID tag.

During specific implementation, the running process of the reader compliance detection is: collecting and analyzing the signal sent by the reader, setting the center frequency, acquisition time, sampling rate and bandwidth parameters to carry out detection;

The reader compliance detection includes time domain signal analysis and reader detection frequency analysis on the signal sent by the reader;

The time-domain signal analysis displays the time-domain waveform after frequency conversion of the signal and various parameters analyzed based on the time-domain waveform;

The reader detection frequency analysis is similar to the tag compliance test analysis content, and also includes the center frequency, frequency drift, adjacent channel leakage ratio and phase analysis of the measured signal.

The communication data module of the reader compliance detection includes decoded data, preamble check and CRC check, and analyzes the measurement value related to the encoding method and the measurement of the reference time T_c.

Through signal monitoring during UHF and microwave band RFID deployment, as well as performance evaluation of readers and tags, the deployment of the system can be effectively optimized, addressing how many antennas to deploy, how to determine the best location for each antenna, and how to determine the optimal location of each antenna. Issues such as the best labeling position of items to achieve the optimization of the RFID deployment process.

Abbreviations:

RFID, Radio Frequency Identification, radio frequency identification, referred to as RFID;

MD, Modulation Depth, modulation depth, also called modulation degree, referred to as MD;

PW, Pulse Width, pulse width, referred to as PW;

UM, Under Modulation, under modulation, also called undershoot, referred to as UM;

OM, Over Modulation, over modulation, also called overshoot, referred to as OM;

ACLR, Adjacent Channel Leakage Ratio, Adjacent Channel Leakage Ratio, ACLR for short;

CRC, Cyclic Redundancy Check, Cyclic Redundancy Check, CRC for short.

The applicant of the present invention has described and described the embodiments of the present invention in detail with reference to the accompanying drawings, but those skilled in the art should understand that the above embodiments are only preferred embodiments of the present invention, and the detailed description is only to help readers better It should be understood that the spirit of the present invention is not limited to the protection scope of the present invention. On the contrary, any improvement or modification made based on the spirit of the present invention should fall within the protection scope of the present invention.

Claims (8)

1. A portable RFID field tester, the tester is used in cooperation with an RFID tag, the tag is an identification object of the RFID field tester, is composed of a coupling element and a radio frequency chip, stores user information, and is installed on the surface of an identified object, and the portable RFID field tester is characterized in that:

the tester comprises a control terminal, a reader and an antenna;

the control terminal controls the work among all the components of the tester;

the reader is a device for reading label information and comprises a control unit and a radio frequency module; the radio frequency module comprises a transmitter and a receiver, the transmitter is used for sending a radio signal to the tag, and the receiver is used for receiving the radio signal of the tag;

the antenna is a transmitting and receiving device for transmitting data between the tag and the reader;

the control terminal controls the reader to send electromagnetic waves through the antenna, after the tag enters the electromagnetic wave magnetic field, a coil in the tag generates induction current, and the tag starts to work and receives radio frequency signals sent by the reader; when the tag is a passive tag, the product information stored in the chip is sent out; when the active tag is an active tag, a radio frequency signal with a certain frequency is actively sent, the reader acquires the signal through the antenna, decodes the signal, sends the decoded signal to a control unit of the reader for related data processing, and finally feeds the decoded signal back to the control terminal to realize data interaction.

2. The portable RFID field tester of claim 1, wherein:

the control terminal of the tester and the control unit of the reader are integrated on a mainboard which takes a programmable embedded dual-core processor as a central chip, and the periphery of the programmable embedded dual-core processor is connected with a power supply management module, a key function module, a capacitance touch module, an asynchronous transceiver module and a radio frequency unit of the reader; the radio frequency unit is an RF agile transceiver;

the key function module and the capacitance touch module are used for realizing data interaction with a user;

the asynchronous transceiver is used for realizing the communication interface function of the detector;

the power supply management module is used for realizing external and internal power supply mode conversion.

3. The portable RFID field tester of claim 1, wherein:

the tester is used for signal monitoring and performance evaluation of the reader and the tag in the RFID deployment process;

the signal monitoring in the RFID deployment process comprises the steps of detecting the RFID deployment environment, analyzing RFID radio frequency communication signaling and evaluating the performance based on a reference label;

the performance evaluation of the reader and the tag is divided into tag conformance detection and reader conformance detection.

4. A portable RFID field tester as defined in claim 3 wherein:

the detection operation process of the RFID deployment environment comprises the following steps:

in the RFID deployment process, a portable RFID field tester and an antenna thereof are placed in an RFID deployment environment, and the tester is used for recording the signal intensity of each channel; and displaying the latest frequency spectrum scanning data in real time in the real-time frequency spectrum analysis bandwidth according to the set frequency, so as to realize the evaluation of the field environment.

5. A portable RFID field tester as defined in claim 3 wherein:

the RFID radio frequency communication signaling analysis and operation process comprises the following steps:

under the condition that the RFID to be tested is in a working state, the portable RFID field tester and the antenna thereof are placed in the working range of the RFID to be tested, the tester is used for analyzing the communication condition of the reader and the tag, the signaling and the time sequence parameter in the working process are recorded, and the function of analyzing the RFID radio frequency communication signaling is realized by analyzing the signaling and the time sequence parameter.

6. A portable RFID field tester as defined in claim 3 wherein:

the performance evaluation operation process based on the reference label comprises the following steps:

under the condition that the RFID to be tested is not in a working state, a portable RFID field tester and matched equipment are placed within the working range of the RFID to be tested, wherein the matched equipment comprises a detection antenna and a reference label suite;

the method comprises the steps that a reference tag is communicated with a reader to be tested, a tester is used for collecting radio frequency signals of a product to be tested to analyze a time domain and a frequency domain, and main parameters of radio frequency performance are obtained, wherein the main parameters comprise working frequency, in-band power, reading distance and writing distance;

when the tested RFID is in an abnormal working state, the reference tag is adopted to replace a failed product with reduced radio frequency performance parameters for verification, and system faults are positioned and diagnosed in an auxiliary mode.

7. A portable RFID field tester as defined in claim 3 wherein:

the label conformity detection process comprises the following steps:

the returned response signal is collected and analyzed by sending an instruction signal to the detected tag;

carrying out modulation depth, pulse width, under modulation or over modulation and frequency domain analysis on the returned response signals;

the modulation depth refers to the ratio of the amplitude of the modulated wave to the amplitude of the carrier wave;

the pulse width is the period for which the pulse can reach the amplitude value;

the under-modulation refers to the ratio of the time that the peak value of the modulation signal is lower than the normal modulation amplitude value to the pulse width time;

the overmodulation refers to the ratio of the time for which certain peaks of the modulation signal exceed the normal modulation amplitude to the pulse width;

the frequency domain analysis comprises the analysis of the center frequency, the frequency drift, the adjacent channel leakage ratio and the phase of the measured signal;

the centre frequency being the theoretical centre frequency of the signal to be measured, using f_oRepresents;

the frequency drift refers to the condition that the output frequency value of the radio frequency equipment changes in a single direction along with the time when the radio frequency equipment continuously works for a long time, and the frequency drift f_ΔUsing actual value f of center frequency of measured signal_meaAnd the theoretical center frequency f_oThe difference of (d) is expressed as:

f_Δ＝f_mea-f_o

the adjacent channel leakage ratio is used for measuring the influence characteristics of the radio frequency equipment on the channels outside the main working frequency when the radio frequency equipment works, and the ratio of the power P (R) of the measured label at the transmitting channel R to the power P (S) of other channels S is expressed as follows:

8. a portable RFID field tester as defined in claim 3 wherein:

the reader conformance detection comprises time domain signal analysis and reader detection frequency analysis of signals sent by the reader;

the time domain signal analysis displays the time domain waveform of the measured signal after frequency conversion and various parameters analyzed based on the time domain waveform;

the reader detection frequency analysis comprises the analysis of the center frequency, the frequency drift, the adjacent channel leakage ratio and the phase of the detected signal.

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