Wireless tag, communication terminal, communication system, and communication method

Abstract

The invention provides a wireless tag, a communication terminal, a communication system and a communication method capable of realizing stable data communication. A communication terminal determines a period of a clock signal generated by a wireless tag based on a prefix signal level drop duration included in obtained tag transmission data as terminal reception data. A communication terminal does not need to independently set a clock signal, and acquires tag information from tag transmission data by using a terminal controller on the basis of the cycle of the clock signal detected by the tag transmission data.

Description

Technical Field

[0001] This invention relates to wireless tags, communication terminals, communication systems, and communication methods. Background Technology

[0002] In recent years, wireless tags have been developed that transmit individual identification information via wireless signals such as RF (Radio Frequency) signals. The identification information of the wireless tags can be read by communication terminals such as wireless tag readers or wireless tag writers.

[0003] As a communication method for reading wireless tag identification information through a communication terminal, start-stop synchronization is known (see, for example, Patent Document 1). In start-stop synchronization, the transmitting and receiving sides operate using a synchronized clock signal. The transmitting side generates transmission data using bit-coded transmission information and uses this transmission data to generate a transmission wave by modulating a preset carrier. The generated transmission wave changes its bit information according to the period of the clock signal. Therefore, after synchronizing the clock signal, the receiving side can obtain the bit information from the received transmission wave.

[0004] In the example of start-stop synchronization, the data length of a single transmission is preset (e.g., eight bits), and the sending side continuously sends "1" (rising signal level) when no information is being transmitted. When transmitting information, the sending side generates transmission data with "0" (falling signal level) to indicate the start of transmission, followed by the preset data length of the transmission information.

[0005] After demodulating the received transmitted wave to obtain the received data, the receiving side parses the received data to obtain identification information, etc. Thus, the receiving side can obtain the information sent by the transmitting side.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: JP1999-355277 Summary of the Invention

[0009] The technical problem to be solved by the present invention

[0010] In Patent Document 1, the transmitting and receiving sides need to generate clock signals with the same period to achieve start-stop synchronization. However, when the wireless tag is powered by electromagnetic waves transmitted by the communication terminal, if the communication terminal's electromagnetic waves are weak, the period of the clock signal generated based on this power supply may be unstable. Furthermore, for various reasons, the period of the clock signal generated by the wireless tag may differ from the period of the clock signals of other wireless tags. In this case, stable data communication between the wireless tag and the communication terminal may not be possible.

[0011] The present invention aims to solve the above problems and provide a wireless tag, communication terminal, communication system and communication method that can achieve stable data communication.

[0012] Technical solutions for solving technical problems

[0013] The wireless tag of the present invention transmits tag transmission data containing tag information of a preset data length to a communication terminal as a tag transmission wave. The wireless tag includes:

[0014] A clock signal generation circuit that generates a clock signal with a preset period;

[0015] A tag controller assigns a prefix of a fixed signal pattern to the tag information to indicate the start of the tag information, and generates tag transmission data according to the period of the clock signal. The tag transmission data includes the prefix and the tag information with varying signal levels.

[0016] A modulation circuit that modulates the tag transmission data generated by the tag controller to generate the tag transmission wave; and

[0017] The tag antenna transmits the tag transmission wave to the communication terminal.

[0018] By enabling the communication terminal to receive the tag transmission wave, the period of the clock signal generated by the clock signal generation circuit is determined for the communication terminal based on the rising and / or falling period of the signal level in the prefix, and the tag information is obtained based on the determined period of the clock signal.

[0019] The communication terminal of the present invention receives a tag transmission wave transmitted by a wireless tag through modulation of tag transmission data containing tag information of a preset data length, and demodulates the tag transmission wave to obtain the tag information. The communication terminal includes:

[0020] A terminal antenna assigns a prefix of a fixed signal pattern to the tag information, indicating the start of the tag information, and receives the tag transmission wave generated by modulating the tag transmission data from the wireless tag according to a clock signal of a preset period generated by the wireless tag. The tag transmission data includes the prefix and the tag information with varying signal levels.

[0021] A signal processing unit that demodulates the tag transmission waveform to generate the tag transmission data; and

[0022] A terminal controller determines the period of the clock signal generated by the wireless tag based on the rising and / or falling period of the signal level in the prefix included in the tag's transmitted data, and acquires the tag information based on the determined period of the clock signal.

[0023] The communication system of the present invention comprises:

[0024] A wireless tag, which modulates tag transmission data containing tag information of a preset data length to transmit as a tag transmission wave; and

[0025] A communication terminal that receives the tag transmission wave transmitted from the wireless tag and demodulates the tag transmission wave to obtain the tag information.

[0026] The wireless tag includes:

[0027] A clock signal generation circuit that generates a clock signal with a preset period;

[0028] A tag controller assigns a prefix of a fixed signal pattern to the tag information to indicate the start of the tag information, and generates tag transmission data according to the period of the clock signal. The tag transmission data includes the prefix and the tag information with varying signal levels.

[0029] A modulation circuit that modulates the tag transmission data generated by the tag controller to generate the tag transmission wave; and

[0030] The tag antenna transmits the tag's transmission wave to the communication terminal.

[0031] The communication terminal includes:

[0032] A terminal antenna that receives the tag-transmitted wave transmitted from the wireless tag;

[0033] The signal processing unit demodulates the tag transmission wave to generate the tag transmission data;

[0034] A terminal controller determines the period of the clock signal generated by the wireless tag based on the rising and / or falling period of the signal level in the prefix included in the tag's transmitted data, and acquires the tag information based on the determined period of the clock signal.

[0035] The communication method of the present invention is a communication method between a wireless tag and a communication terminal. The wireless tag modulates tag transmission data containing tag information of a preset data length as a tag transmission wave and transmits it. The communication terminal receives the tag transmission wave transmitted from the wireless tag and demodulates the tag transmission wave to obtain the tag information.

[0036] The wireless tag performs the following steps:

[0037] The clock signal generation step involves generating a clock signal with a preset period through a clock signal generation circuit.

[0038] The tag transmission data generation step involves assigning a prefix of a fixed signal pattern indicating the start of the tag information to the tag information, and generating the tag transmission data through a tag controller according to the period of the clock signal. The tag transmission data includes the prefix and the tag information with varying signal levels.

[0039] The modulation step involves modulating the tag transmission data generated by the tag controller using a modulation circuit to generate the tag transmission wave; and

[0040] The transmission step involves sending the tag transmission wave from the tag antenna to the communication terminal.

[0041] The communication terminal performs the following steps:

[0042] The receiving step involves receiving the tag-transmitted wave from the wireless tag via the terminal antenna;

[0043] The demodulation step involves demodulating the tag's transmitted waveform to generate the tag's transmitted data via a signal processing unit; and

[0044] The acquisition step involves using the terminal controller to determine the period of the clock signal generated by the wireless tag based on the rising and / or falling period of the signal level in the prefix contained in the data transmitted by the tag, and acquiring the tag information based on the determined period of the clock signal.

[0045] Invention Effects

[0046] This invention utilizes a prefix assigned to the tag information to enable the communication terminal to detect the period of the clock signal generated by the clock signal generation circuit of the wireless tag. Based on the detected clock signal period, the communication terminal obtains the tag information. Therefore, even if the period of the clock signal generated by the wireless tag fluctuates, the communication terminal can still obtain the tag information. This achieves stable data communication. Attached Figure Description

[0047] Figure 1 It is a block diagram representing the circuit structure of a wireless tag.

[0048] Figure 2 It is a block diagram representing the circuit structure of a communication terminal.

[0049] Figure 31001 is a schematic diagram showing the waveform of the terminal transmitting the wireless tag; 1002 is a schematic diagram showing the output of the rectifier circuit of the wireless tag; 1003 is a schematic diagram showing the waveform of the clock signal generated by the wireless tag; 1004 is an explanatory diagram to illustrate the tag information of the wireless tag; 1005 is a schematic diagram showing the waveform of the tag transmitting data generated by the wireless tag; 1006 is a schematic diagram showing the waveform of the tag transmitting wave generated by the wireless tag.

[0050] Figure 4 1011 is a schematic diagram representing the clock signal waveform; 1012 is a schematic diagram representing the tag data transmission generated according to the period of the clock signal 1011.

[0051] Figure 5 1021 is a schematic diagram representing the clock signal waveform; 1022 is the tag transmission data generated based on the period of the clock signal in 1021, which is... Figure 4 The image shown in 1012 is an enlarged view of the information transmission period.

[0052] Figure 6 It is a flowchart representing the data transmission and processing flow in a wireless tag.

[0053] Figure 7 It is a flowchart illustrating the data reception and processing flow in a communication terminal.

[0054] Figure 8 This is a flowchart representing the process of obtaining and processing tag information.

[0055] Figure 9 1031 is a schematic diagram of the tag transmitting data waveform when the width TA of one period of the clock signal is small; 1032 is a schematic diagram of the tag transmitting data waveform when the width TB of one period of the clock signal is larger than the width TA.

[0056] Figure 10 1041 is a schematic diagram showing the waveform of a clock signal; 1042 is a schematic diagram showing tag transmission data (1) generated according to the period of the clock signal in another embodiment for the purpose of explaining 1041.

[0057] Figure 11 1051 is a schematic diagram showing the waveform of a clock signal; 1052 is a schematic diagram showing tag transmission data (2) generated according to the period of the clock signal in another embodiment for the purpose of explaining 1051.

[0058] Figure 12 1061 is a schematic diagram showing the waveform of a clock signal; 1062 is a schematic diagram showing tag transmission data (3) generated according to the period of the clock signal in another embodiment for the purpose of explaining 1061.

[0059] Figure 13 1071 is a schematic diagram representing the clock signal waveform; 1072 is a schematic diagram representing the tag data transmission waveform; 1073 is a schematic diagram representing the terminal receiving data (1) waveform where the timing of the signal level drop and rise occurs.

[0060] Figure 14 1081 is a schematic diagram of the clock signal waveform; 1082 is a schematic diagram of the tag data transmission waveform; 1083 is a schematic diagram of the terminal receiving data (2) waveform where the timing of the signal level drop and rise occurs. Detailed Implementation

[0061] The embodiments of the present invention will now be described with reference to the accompanying drawings.

[0062] <Overview of Communication Systems>

[0063] Figure 1 This is a block diagram showing the circuit structure of the wireless tag 1 in this embodiment. Figure 2 This is a block diagram showing the circuit structure of the communication terminal 2 in this embodiment. The communication system consists of... Figure 1 The wireless tag 1 shown is Figure 2 The communication terminal 2 shown is configured such that, for example, multiple wireless tags 1 are pre-installed on a device or product, etc. When a user with the communication terminal 2 moves to the respective location of the wireless tag 1, the user can bring the communication terminal 2 close to the wireless tag 1 to achieve data communication between the wireless tag 1 and the communication terminal 2.

[0064] It should be noted that data communication between wireless tag 1 and communication terminal 2 can be performed using shortwave frequency bands (13.56 MHz), UHF frequency bands (860–960 MHz), microwave frequency bands (2400–2483.5 MHz), etc., which are powered by electromagnetic induction, in accordance with the prescribed communication standards.

[0065] At this time, the communication system transmits a carrier wave (hereinafter referred to as the terminal transmission wave) from communication terminal 2 to wireless tag 1. When wireless tag 1 receives the terminal transmission wave from communication terminal 2, the radio wave energy of the terminal transmission wave powers wireless tag 1. Wireless tag 1 is powered by the radio wave energy of the terminal transmission wave to start and generate a clock signal. Furthermore, wireless tag 1 uses the clock signal to activate tag controller 15, generating tag transmission data containing a prefix with a fixed signal pattern and the tag's inherent identification information, i.e., tag information. Thus, wireless tag 1 generates the prefix and tag information through tag controller 15, modulates the obtained tag transmission data, generates a carrier wave (hereinafter referred to as the tag transmission wave), and transmits the tag transmission wave to communication terminal 2.

[0066] When communication terminal 2 receives the tag transmission wave from wireless tag 1, it demodulates the wave and detects the prefix contained in the tag transmission data. Then, based on the rise and fall of the signal level of the prefix composed of a fixed signal pattern, communication terminal 2 determines the period of the clock signal generated by wireless tag 1. Thus, communication terminal 2 can determine the period of the clock signal used by wireless tag 1 when generating tag transmission data, and can obtain the tag information contained in the tag transmission data based on the determined period of the clock signal without generating a clock signal independently.

[0067] Thus, based on the prefix assigned to the tag information in the wireless tag 1, the communication system of this embodiment can use the communication terminal 2 to determine the period of the clock signal generated by the wireless tag 1. Therefore, even if the period of the clock signal generated by the wireless tag 1 is different from the period of the clock signal generated by other wireless tags (not shown) for some reason, the communication terminal 2 can still obtain the tag information based on the determined period of the clock signal of the wireless tag 1.

[0068] <The Composition of Wireless Tags>

[0069] The following details wireless tag 1. Figure 1 As shown, the wireless tag 1 includes, for example, an RF (radio frequency) antenna 11, a rectifier circuit 12, a clock signal generation circuit 13, an ID data recording unit 14, a tag controller 15, and a modulation circuit 16. The tag antenna 11 can receive and transmit radio waves that can communicate with the communication terminal 2, such as shortwave (13.56 MHz) waves, UHF (860–960 MHz) waves, and microwave (2400–2483.5 MHz) waves, using electromagnetic induction. At this time, the tag antenna 11 receives the terminal transmission wave sent by the communication terminal 2, and simultaneously transmits the generated tag transmission wave to the communication terminal 2 based on the reception of the terminal transmission wave.

[0070] Figure 31001 represents an example waveform of the terminal transmission wave received by the wireless tag 1. In this embodiment, the wireless tag 1 is not equipped with a power supply; power is supplied to each circuit based on the terminal transmission wave received by the communication terminal 2. The tag antenna 11 is tuned to the frequency band of the terminal transmission wave transmitted by the communication terminal 2, and AC power is generated based on the received terminal transmission wave. A current corresponding to the intensity of the received terminal transmission wave is generated in the tag antenna 11, and since the terminal transmission wave is an AC signal, positive and negative currents are generated alternately.

[0071] The rectifier circuit 12 has the function of converting AC to DC, and is used to rectify the AC power excited by the tag antenna 11 into DC power. Figure 3 The fixed DC power shown in 1002 is output to the clock signal generation circuit 13, etc. At this time, the rectifier circuit 12 is, for example, a bridge full-wave rectifier circuit using multiple rectifier elements (e.g., point-contact semiconductor diodes) to generate DC power from a positive power of a certain intensity to drive the wireless tag 1.

[0072] It should be noted that the rectifier circuit 12 can not only rectify AC power into DC power, but also boost the DC power and output the resulting DC voltage to a battery (not shown) to charge it. Furthermore, although the case where the wireless tag 1 operates using DC power generated by the rectifier circuit 12 has been described here, the invention is not limited to this; the wireless tag 1 can also be operated using a pre-set battery power supply.

[0073] The clock signal generation circuit 13 is based on the DC power output from the rectifier circuit 12, such as... Figure 3 As shown in 1003, the rise duration (also known as the rise period) and fall duration (also known as the fall period) of the signal level are fixed, and a clock signal with a periodically alternating rise and fall period is generated. The clock signal generation circuit 13 outputs the obtained clock signal to the tag controller 15, which will be described later.

[0074] The ID data recording unit 14 pre-records a unique identifier specifically set for the wireless tag 1 as tag information. In this embodiment, the tag information is, for example, identification information used by the communication terminal 2 to identify the wireless tag 1, such as… Figure 3 As shown in 1004, it is a binary signal with a preset number of bits (data length) represented by "0" and "1". The tag information in this embodiment will be described below as an example of the identification information of wireless tag 1 represented by the binary signal "10110101".

[0075] It should be noted that although this embodiment uses the tag information of the wireless tag as an example to illustrate the application of the identification information of the wireless tag 1 as tag information, the present invention is not limited to this. For example, in a wireless tag equipped with a sensor or computing circuit, in addition to the identification information of the wireless tag, it may also include temperature information measured by the sensor, various detection information detected by the sensor, and computing information calculated by the computing circuit as tag information. In this case, the communication terminal 2 can not only identify the wireless tag, but also obtain the temperature information, detection information, computing information, etc. obtained by the wireless tag. For the sake of simplicity, the following explanation will use the case where the identification information of the wireless tag 1 is used as tag information as an example.

[0076] The tag controller 15 reads the tag information recorded in the ID data recording section 14 and assigns a prefix (described later) to the tag information, which includes standby information, the prefix, and tag information. Therefore, the tag controller 15 generates tag transmission data that sequentially follows the standby information with the prefix and tag information. Figure 3 (1005).

[0077] in, Figure 4 1011 is a schematic diagram representing the clock signal waveform. Figure 4 1012 is through Figure 4 A waveform diagram illustrating the tag transmission data generated from the standby information, prefix, and tag information of the 1011 clock signal. (See diagram below.) Figure 4 As shown in 1012, the tag transmission data has a standby period and an information transmission period. In this embodiment, the tag transmission data has a standby period with a continuous rising signal level before the prefix period of the information transmission period, and the standby period and the information transmission period are configured alternately.

[0078] The standby period is a data length longer than the tag information data length (bit length), and it is a period during which standby information with a continuous signal level different from the signal level at the beginning of the prefix is ​​generated. Since the tag information data length is eight bits, the standby period is set to a data length of nine bits, only one bit longer than the tag information data length. Furthermore, since the prefix beginning is set to a falling signal level, a rising signal level different from the prefix signal level is generated continuously during the standby period.

[0079] Tag controller 15, for example, generates a rising signal level of a preset data length represented by "1" in binary as standby information, such as... Figure 4 As shown in Figure 1012, a signal is generated to change the rising or falling timing of the "1" in the standby information based on the rising and falling timing of the clock signal. It should be noted that... Figure 4In 1012, the data length from the start time (also called the start time) t1 of the standby period to the end time (also called the end time) t2 of the standby period is nine bits. Between time t1 and t2, the rising signal level continues continuously. Here, the start time t1 of the standby period is the time when the preset rising edge is generated, and the end time t2 of the standby period is the time when the falling edge is generated after the preset data length of continuous rising signal level starts from the start time t1.

[0080] The information transmission period during the standby period consists of the period for generating the prefix correlation signal (hereinafter also referred to as the prefix period) and the period for generating the tag information correlation signal (referred to as the tag information period), with the tag information period immediately following the prefix period.

[0081] The prefix is ​​also called SOF (Start Of Frame), and is, for example, preset in the tag controller 15. The prefix indicates the start of tag information in the tag transmission data and is a binary signal with a fixed signal pattern represented by "0" and "1". In this embodiment, the following description will take the "010" signal pattern, which immediately follows the standby period and changes the signal level in the order of falling, rising, and falling, as an example of the prefix.

[0082] In this embodiment, the tag controller 15 appends standby information after the prefix and tag information represented by binary "0" and "1". For example, it sets "0" in the prefix and tag information as falling and "1" as rising. Figure 4 As shown in 1011, the timing is based on the rise and fall of the clock signal ( Figure 4 (Only the rising timing case is shown in 1012), a signal is generated that changes the falling timing of "0" and the rising timing of "1" in the prefix and tag information.

[0083] Therefore, during standby, the tag transmission data generates standby information with a rising signal level that is longer than the data length of the tag information. Furthermore, during information transmission, the tag transmission data generates tag information represented by a binary signal (here, "010") with a fixed signal pattern that begins with a falling signal level, different from the rising signal level of the standby information, and a preset binary signal (here, "10110101"). The tag controller 15 outputs the generated tag transmission data to the modulation circuit 16. Figure 1 ).

[0084] Modulation circuit 16 transmits data via terminal transmission wave modulation tag received from communication terminal 2, generating data such as... Figure 3The tag transmits a wave as shown in Figure 1006. Thus, the tag antenna 11 transmits the tag transmit wave generated by the modulation circuit 16 as a reflected wave of the terminal transmit wave to the communication terminal 2. It should be noted that although this embodiment describes the case where tag transmission data is modulated based on the terminal transmit wave received by the communication terminal 2, and the reflected wave (radio wave) of that terminal transmit wave is transmitted from the wireless tag 1 to the communication terminal 2 as the tag transmit wave, the present invention is not limited to this. For example, the wireless tag 1 may also be configured with a transmit wave generation unit, using a carrier generated by the transmit wave generation unit to modulate the tag transmission data to generate the tag transmit wave.

[0085] <Composition of Communication Terminals>

[0086] The communication terminal 2 will be described in detail below. In this embodiment, the communication terminal 2 is a reader or reader-writer, such as... Figure 2 As shown, the communication terminal 2 includes, for example, a terminal antenna 21 (such as an RF antenna), a signal processing unit 22, a carrier generation unit 23, a terminal controller 24, a communication module 25, and a battery 26. The battery 26 is the power source for supplying power to various circuits within the communication terminal 2.

[0087] The terminal antenna 21 is capable of transmitting and receiving radio waves that can communicate with the wireless tag 1, such as shortwave (13.56 MHz), UHF (860–960 MHz), and microwave (2400–2483.5 MHz) waves, which are transmitted via electromagnetic induction. At this time, the terminal antenna 21 transmits a terminal transmission wave to the wireless tag 1, and simultaneously receives the tag transmission wave transmitted by the wireless tag 1 based on whether the wireless tag 1 receives the terminal transmission wave.

[0088] The signal processing unit 22 includes circuits that perform various signal processing required for communication, such as analog circuits for digital-to-analog conversion, matching circuits, and demodulation circuits. For example, the signal processing unit 22 uses the matching circuit to match the impedance of the tag antenna 11 with the circuitry within the communication terminal 2, ensuring the communication performance of the terminal antenna 21. Furthermore, the signal processing unit 22 demodulates the tag transmission wave received by the terminal antenna 21 using the demodulation circuit, generating a demodulated signal with the carrier (reflected wave) component removed. The carrier generation unit 23 includes an oscillator that generates a terminal transmission wave at a preset frequency.

[0089] The terminal controller 24 demodulates the tag transmission wave from the signal processing unit 22 and performs analog-to-digital conversion on the demodulated signal to generate the tag transmission data generated by the wireless tag 1 into terminal reception data. The terminal controller 24 analyzes the rise and fall of the signal level of the obtained tag transmission data (terminal reception data) and determines the period of the clock signal used in the wireless tag 1 to generate the tag transmission data based on the rise and fall of the prefix signal level during information transmission.

[0090] Specifically, the terminal controller 24, such as Figure 4 As shown in Figure 1012, when the signal level changes to a falling signal after nine consecutive rising signal levels in the tag's transmitted data, it is determined that the signal level has shifted from the standby period to the information transmission period. The signal level that changes in the order of falling, rising, and falling after the continuous rising standby period is determined as the prefix.

[0091] In the tag-transmitted data, a bit of information represented by one rising or one falling digit is as follows: Figure 4 As shown in 1011 and 1012, the clock signal is transmitted within one cycle (1CLC) of a clock signal consisting of falling and rising edges. Therefore, the terminal controller 24 can determine one cycle of the clock signal by detecting the duration of the falling edge at the beginning of the prefix (the falling period, i.e., the time from the beginning of the falling edge to the next rising edge). Then, the terminal controller 24 can obtain the data communication speed [bit / sec] by calculating the reciprocal of the determined clock signal cycle.

[0092] In this way, the terminal controller 24 can determine the period of the clock signal generated by the wireless tag 1 by detecting the prefix fall duration, which is equivalent to one cycle (1CLC) of the clock signal. Within the prefix signal levels that change in the order of falling, rising, and falling, the terminal controller 24 sequentially detects the rising and falling signal levels that occur after the last falling edge based on the determined clock signal period, and acquires the detected signal level of a preset data length (here, eight bits) as tag information.

[0093] in, Figure 5 1021 and 1022 are... Figure 4 The images shown in 1011 and 1012 are magnified views of the information transmission period area. The following uses... Figure 5 Sections 1021 and 1022 detail the tag information acquisition process through which the terminal controller 24 acquires tag information. At this time, as described above, the terminal controller 24 measures the duration of the fall at the beginning of the prefix, i.e., times t2 to t3, and determines the time t2 to t3 as one cycle (1CLC) of the clock signal. Among the prefix signal levels (signal levels at times t2 to t5) that change in a falling, rising, and falling sequence, the terminal controller 24 sets the time t4 of the last falling edge as the reference time t4.

[0094] In this embodiment, the terminal controller 24 is pre-set to determine the signal level sequentially from a predetermined reference time t4 to tg8 at preset intervals, using a predetermined reference time t4 as a reference. For example, in the terminal controller 24 of this embodiment, the following times are pre-set as the times for determining the signal level: 1.5 times the clock signal cycle (denoted as 1.5CLC) tg1, 2.5 times the clock signal cycle (denoted as 2.5CLC) tg2, 3.5 times the clock signal cycle (denoted as 3.5CLC) tg3, 4.5 times the clock signal cycle (denoted as 4.5CLC) tg4, 5.5 times the clock signal cycle (denoted as 5.5CLC) tg5, 6.5 times the clock signal cycle (denoted as 6.5CLC) tg6, 7.5 times the clock signal cycle (denoted as 7.5CLC) tg7, and 8.5 times the clock signal cycle (denoted as 8.5CLC) tg8.

[0095] For example, the terminal controller 24 receives data from the terminal (tag transmission data) and reads the signal level at time tg1, which is 1.5 CLC later than the reference time t4. The read signal level is then used as a bit of tag information. Similarly, the terminal controller 24 receives data from the terminal and sequentially reads the signal levels at times tg2, tg3, tg4, tg5, tg6, tg7, and tg8, which are 2.5 CLC later than the reference time t4, and determines whether the read signal level is rising or falling.

[0096] The terminal controller 24 takes the rising signal level as "1" and the falling signal level as "0", and obtains one to eight bits of information of the tag information using the signal level represented by "0" and "1" in binary, and obtains the tag information represented by the preset binary signal ("10110101").

[0097] It should be noted that in this embodiment, the tag information acquired by the terminal controller 24 is output from the terminal controller 24 to the communication module 25. The communication module 25 is, for example, a communication interface capable of sending and receiving data with an external device, used to send the tag information of the wireless tag 1 acquired by the terminal controller 24 to the external device. The external device is, for example, an information processing device such as a display device or a personal computer, used to apply the tag information acquired by the communication terminal 2 to various services such as product management or data browsing for devices equipped with the wireless tag 1.

[0098] It should be noted that although this embodiment describes the case where the tag information acquired by the terminal controller 24 is output from the terminal controller 24 to the communication module 25, the present invention is not limited thereto. For example, the communication terminal 2 may also be configured to use the acquired tag information to perform judgment processing or management processing, and to prompt the user with the processing results through a prompt section (not shown) for device management or product management, etc.

[0099] <Data transmission processing in wireless tags>

[0100] The following uses Figure 6 The flowchart illustrates the data transmission process performed by wireless tag 1 when data is transmitted and received between wireless tag 1 and communication terminal 2. For example... Figure 6 As shown, in step S11, after the wireless tag 1 receives the terminal transmission wave sent by the communication terminal 2 through the tag antenna 11, it proceeds to the next step S12.

[0101] In step S12, the wireless tag 1 rectifies the AC power generated when the tag antenna 11 receives the transmitted wave in step S11 through the rectifier circuit 12, and finally supplies the obtained DC power to each circuit of the wireless tag 1 before proceeding to the next step S13. In step S13, the wireless tag 1 activates the clock signal generation circuit 13, which generates a clock signal as shown in the figure. Figure 4 The clock signal shown in 1021 proceeds to the next step, S15.

[0102] In step S15, the wireless tag 1 activates the tag controller 15 via the clock signal generated in step S13, reads tag information from the ID data recording unit 14, and assigns a prefix to the tag information, including standby information, prefix, and tag information. Thus, the wireless tag 1 generates tag transmission data via the tag controller 15, which sequentially appends the prefix and tag information after the standby information. Figure 3 (1005), proceed to the next step S16.

[0103] In step S16, the wireless tag 1 modulates the tag transmission data generated in step S15 based on the terminal transmission wave received by the communication terminal 2 through the modulation circuit 16 to generate a tag transmission wave, and proceeds to the next step S17. In step S17, the wireless tag 1 transmits the tag transmission wave generated in step S16 to the communication terminal 2 through the tag antenna 11, ending the above data transmission processing flow.

[0104] Data Reception and Processing in Communication Terminals

[0105] Next, use Figure 7 The flowchart illustrates the data reception process performed by communication terminal 2 when wireless tag 1 and communication terminal 2 transmit and receive data. For example... Figure 7 As shown, after the communication terminal 2 sends the terminal transmission wave from the terminal antenna 21, it enters step S21 from the initial step, receives the terminal transmission wave through the wireless tag 1, and thus receives the tag transmission wave sent by the wireless tag 1 through the terminal antenna 21, and enters the next step S22.

[0106] In step S22, the communication terminal 2 performs various signal processing operations, such as demodulation processing, on the tag transmission wave received in step S21 through the signal processing unit 22 to generate a demodulated signal. The obtained demodulated signal is then output to the terminal controller 24 before proceeding to the next step, S23. In step S23, the communication terminal 2 performs tag information acquisition processing on the demodulated signal obtained in step S22 through the terminal controller 24, generating tag transmission data as terminal received data and acquiring tag information from this tag transmission data, thus ending the above processing.

[0107] Among them, use Figure 8 The flowchart illustrates the tag information acquisition process performed in step S23. For example... Figure 8 As shown, in step S231, the terminal controller 24 determines whether a continuously rising signal level longer than the preset data length has been detected. If a negative result is obtained in step S231, it indicates that a continuously rising signal level longer than the preset data length has not been detected, meaning that the standby information detection has not yet been completed. In this case, the terminal controller 24 will continue to wait until a positive result is obtained in step S231.

[0108] Conversely, if a positive result is obtained in step S231, it indicates that a continuous rising signal level longer than the preset data length has been detected, that is, the standby information detection has been completed, and the terminal controller 24 proceeds to the next step S232.

[0109] In step S232, the terminal controller 24 determines whether a falling edge has been detected after the standby information detection. If a negative result is obtained in step S232, it indicates that no falling edge has been detected, and the terminal controller 24 will continue to wait until a falling edge is detected.

[0110] Conversely, if a positive result is obtained in step S232, it indicates that a falling edge has been detected. At this time, the terminal controller 24 determines that the first bit of the prefix has been detected and proceeds to the next step S233. In step S233, the terminal controller 24 measures the time from the falling edge and proceeds to the next step S234.

[0111] In step S234, the terminal controller 24 determines whether a rising edge has been detected. If a negative result is obtained in step S234, it indicates that no rising edge has been detected, meaning that the signal level has remained at a falling level since the falling edge. In this case, the terminal controller 24 will continue to wait until a rising edge is detected.

[0112] Conversely, if a positive result is obtained in step S234, it indicates that a rising edge has been detected, meaning the signal level changes from falling to rising. At this point, the terminal controller 24 proceeds to the next step, S235. In step S235, the terminal controller 24 ends the time measurement starting from the falling edge, determines the period of the clock signal based on the falling duration measured from the falling edge to the rising edge, and proceeds to the next step, S236.

[0113] In step S236, the terminal controller 24 again determines whether a falling edge has been detected. If a negative result is obtained in step S236, it indicates that no falling edge has been detected, meaning that the signal level has remained at a rising level since the rising edge. In this case, the terminal controller 24 will continue to wait until a falling edge is detected.

[0114] Conversely, if a positive result is obtained in step S236, it indicates that a falling edge has been detected, meaning the signal level changes from rising to falling. At this point, the terminal controller 24 proceeds to the next step, S237. In step S237, the terminal controller 24 determines that the detected second falling edge is the last falling edge of the prefix, sets the time t4 at which the falling edge was detected as the reference time t4, and proceeds to the next step, S238.

[0115] In step S238, the terminal controller 24, based on the period of the clock signal determined in step S235, sequentially determines whether the signal level is rising or falling at preset signal level reading times tg1 to tg8 starting from the reference time t4, obtains tag information of preset data length (eight bits), and then ends the above tag information acquisition process.

[0116] <Functions and Effects>

[0117] In the above configuration, the communication system of this embodiment includes:

[0118] Wireless tag 1, which modulates tag transmission data containing tag information of a preset data length to transmit as a tag transmission wave; and

[0119] Communication terminal 2 receives the tag transmission wave sent from the wireless tag, demodulates the tag transmission wave, and obtains the tag signal.

[0120] When wireless tag 1 communicates with communication terminal 2, it generates a clock signal with a preset period through clock signal generation circuit 13.

[0121] Furthermore, the wireless tag 1 assigns a prefix indicating the start of a fixed signal pattern to the tag information via the tag controller 15, and generates tag transmission data according to the period of the clock signal. This tag transmission data includes a prefix indicating signal level changes and tag information. The wireless tag 1 modulates the tag transmission data generated by the tag controller 15 via the modulation circuit 16 to generate a tag transmission wave, and transmits the tag transmission wave from the tag antenna 11 to the communication terminal 2.

[0122] Communication terminal 2 demodulates the tag transmission wave received by terminal antenna 21 through signal processing unit 22 to generate terminal received data from the tag transmission data. Then, communication terminal 2 determines the period of the clock signal generated by wireless tag 1 based on the duration of the prefix signal level drop contained in the acquired tag transmission data, which is the terminal received data. Communication terminal 2 can obtain tag information from the tag transmission data based on the period of the clock signal detected by terminal controller 24, without having to set the clock signal independently.

[0123] In this embodiment, since the wireless tag 1 is powered by a terminal transmission wave from the communication terminal 2, unstable reception of the terminal transmission wave may cause the clock signal generation circuit 13 to operate unstably, resulting in a different period for the clock signal generated by the clock signal generation circuit 13 compared to the clock signals of other wireless tags. Furthermore, other factors may also cause a difference in the period of the clock signal generated by the wireless tag 1 compared to the clock signals of other wireless tags.

[0124] The communication terminal 2 in this embodiment can determine the period of the clock signal generated by the wireless tag 1 based on the prefix assigned to the tag information, and acquire tag information based on the detected period of the clock signal. Therefore, even if the communication terminal 2 encounters... Figure 9 The clock signal generated by wireless tag 1 as shown in 1031 has a cycle width TA that becomes smaller, or as... Figure 9 Even if the clock signal period generated by wireless tag 1 shown in Figure 1032 becomes a width TB that is larger than the width TA, assuming that the period of the clock signal generated by wireless tag 1 varies from person to person, tag information can still be obtained without being affected by clock period fluctuations. This achieves stable data communication between wireless tag 1 and communication terminal 2.

[0125] Furthermore, in this communication system, the period of the clock signal generated by the wireless tag 1 is detected by the communication terminal 2 based on the prefix assigned to the tag information in the wireless tag 1. Therefore, the communication system of this embodiment does not require synchronizing the clock signal of the wireless tag 1 with the clock signal of the communication terminal 2, nor does it require synchronizing the clock signal of the communication terminal 2 with the clock signal of the wireless tag 1. This eliminates the need for a clock signal synchronization processing circuit, which helps to reduce the circuit size of the wireless tag 1 and the communication terminal 2.

[0126] <Other Implementation Methods>

[0127] It should be noted that although the above embodiments describe the case where the communication terminal 2 determines the period of the clock signal generated by the wireless tag 1 based on the time from the signal level in the prefix to its rise (fall period), the present invention is not limited thereto. For example, in other embodiments, the communication terminal 2 may also determine the period of the clock signal generated by the wireless tag 1 based on the time from the signal level in the prefix to its rise (rise period).

[0128] Furthermore, regarding the communication terminal 2 in the above embodiment, although it is described that the period of the clock signal generated by the wireless tag 1 is determined by the communication terminal 2 based on the time from the falling to the rising of the prefix (falling period) detected after detecting standby information of a continuous rising signal level in the tag transmission data, the present invention is not limited thereto. For example, the communication terminal 2 may also be as follows: Figure 10 As shown in 1041 and 1042, the period of the clock signal generated by the wireless tag 1 is determined by the communication terminal 2 based on the time (descent period and rise period) of the prefix detected after detecting the standby information of the continuous rising signal level in the tag transmission data from the falling signal level.

[0129] Thus, the communication terminal 2 can not only generate the falling duration (fall period) based on one cycle of the clock signal, but also further combine it with the rising duration (rise period) generated by the next cycle of the clock signal to determine the period of the clock signal from two cycles A (here, two cycles are marked as 1 unit A, A = 2CLC). In this case, the same effect as the above implementation method can be achieved.

[0130] Furthermore, in the above embodiment, although the clock signal period (1CLC) is determined based on the prefix of the tag transmission data, and the detection time t4 of the last falling edge of the prefix is ​​used as the reference time t4, and the signal level is determined sequentially from the reference time t4 at 1.5 times the clock signal period (1.5CLC) tg1, 2.5 times the clock signal period (2.5CLC) tg2, etc., to obtain tag information, the present invention is not limited to this. Other embodiments include, for example... Figure 10 As shown in 1041 and 1042, the two periods A of the clock signal, which is equivalent to two bits at the beginning of the prefix falling and rising, can be determined as a unit, and the time tg1, tg2, ... of determining the signal level can be set based on the determined two periods A.

[0131] At this time, communication terminal 2 uses the detection time t4 of the last falling edge of the prefix as the reference time t4. Starting from this reference time t4, it sequentially determines the signal level at 0.75 times (0.75A)tg1, 1.25 times (1.25A)tg2, and so on, based on two clock signal cycles A, to obtain tag information. This tag information acquisition process can achieve the same effect as the above-described implementation method.

[0132] Furthermore, although the above embodiments describe the use of a prefix composed of falling, rising, and falling signal levels, the present invention is not limited thereto. For example, if it is a standby information with a continuous falling signal level, a prefix composed of rising, falling, and rising signal levels can be used. Moreover, other embodiments may also be as follows... Figure 11 As shown in 1051 and 1052, a prefix is ​​used that alternates between falling and rising two or more times.

[0133] exist Figure 11 In the prefix shown in 1052, the falling "0" and the rising "1" are repeated alternately multiple times, forming a structure of "0101010" with "01" repeated three times followed by "0". In this case, the terminal controller 24 can generate the falling duration (time t2 to t3) through one cycle of the clock signal, similar to the above embodiment. Figure 11 Although time t3 in 1052 is not shown, it is located between time t2 and t4 to determine the period of the clock signal. Furthermore, the period of the clock signal is determined from the two periods of the clock signal by combining the rise duration generated by one period of the clock signal.

[0134] Furthermore, the terminal controller 24 can calculate one period (1CLC) or the average value of the two periods A from the two periods A (=2CLC) of the clock signal, and determine the period of the clock signal based on the calculated average value. Specifically, the terminal controller 24 as follows: Figure 11As shown in Figure 1052, for example, when there are three periods A, the average value of the two periods A is calculated from these three periods A. The terminal controller 24 uses the detection time t8 of the last falling edge of the prefix as the reference time t8, and from the reference time t8, it sequentially determines the signal level to obtain tag information by determining the time (0.75A)tg1, the time (1.25A)tg2, etc., of the two periods A of the average value. This tag information acquisition process can achieve the same effect as the above implementation method.

[0135] Furthermore, although the above embodiments describe the generation of a rising and falling prefix in each cycle of the clock signal consisting of rising and falling elements, the invention is not limited thereto. In other embodiments, for example... Figure 12 As shown in Figures 1061 and 1062, a falling and rising edge of the prefix can also be generated using a clock signal at half a cycle instead of a full cycle. Furthermore, regarding the timing of generating the rising and falling edges of the prefix, the timing can be different, using either a full cycle or half a cycle of the clock signal. It should be noted that although in... Figure 12 In 1062, an example is shown where the first falling and rising of the prefix are generated in time with half a cycle of the clock signal, and the remaining last falling of the prefix is ​​generated in time with one cycle of the clock signal, but all falling and rising of the prefix can be generated in time with half a cycle of the clock signal.

[0136] At this time, the tag controller 15 generates the first falling signal level of the prefix during the rising period of half a clock cycle (time t2~t2'), and generates the next rising signal level of the prefix during the falling period of the next half clock cycle (time t2'~t3). Further, the tag controller 15 generates the last falling signal level of the prefix during the rising and falling periods of the next clock cycle.

[0137] The terminal controller 24 measures the time (t2 to t3) from the fall to the rise of the prefix, which corresponds to one period of the clock signal, after the standby information detection. Then, based on the measured time from the fall to the rise of the prefix, the terminal controller 24 determines the period of the clock signal generated by the wireless tag 1 and sets the detection time t3 of the fall edge of the prefix as the reference time t3.

[0138] The terminal controller 24, based on the determined period of the clock signal, starts from the reference time t3 and sequentially determines the signal level at 1.5 times the time (1.5B)tg1, 2.5 times the time (2.5B)tg2, and so on, according to one period B of the clock signal, to acquire tag information. This tag information acquisition process can achieve the same effect as the above-described implementation method. It should be noted that, as Figure 12As shown in Figure 1062, times tg1 to tg8 are equivalent to 1.5CLC to 8.5CLC when one period B of the clock signal is 1CLC.

[0139] It should be noted that, although the other embodiments described above are as follows... Figure 12 Figures 1061 and 1062 show the case where the first falling and rising edge of the prefix is ​​generated in half a cycle of the clock signal, rather than a full cycle, but the invention is not limited thereto. For example, a falling and rising edge of the prefix can also be generated in any preset period that is a multiple of half a cycle (0.5CLC) of the clock signal.

[0140] It should be noted that the timing of the rise and fall in the terminal received data generated by communication terminal 2 based on the tag transmission wave may deviate from the timing of the rise and fall in the tag transmission data generated by wireless tag 1. Such timing offset may be caused by various factors such as the modulation processing capability of wireless tag 1, the surrounding environment for wireless communication, and the demodulation processing capability of communication terminal 2.

[0141] in, Figure 13 1071 is a schematic diagram representing the clock signal waveform. Figure 13 The 1072 is a schematic diagram representing the tag data transmission generated according to the period of this clock signal. Figure 13 The 1073 indicates terminal received data generated based on tag-transmitted waves. Figure 13 The terminal receiving data, as shown in 1073, experiences a signal level drop in timing (times t2", t4", etc.) earlier than the data transmission time of the tag due to some reason. Figure 13 In 1072), the signal level drop timing (times t2, t4, tg1, etc.) is specified. This causes the drop time t2” of the first signal level in the prefix of the terminal received data to occur only |t2-t2”| time earlier than the drop time t2 of the first signal level in the prefix of the tag transmitted data, resulting in a corresponding offset.

[0142] Furthermore, the signal level rise timing (time t3”, etc.) in the terminal's received data is later than the signal level rise timing (times t3, t5, tg2, etc.) in the tag's transmitted data. This results in the rise time t3” of the first signal level in the prefix of the terminal's received data being delayed by only |t3”-t3| time compared to the rise time t3 of the first signal level in the prefix of the tag's transmitted data, thus creating a corresponding offset.

[0143] At this time, the terminal controller 24 preferably acquires the tag information in the following manner. The terminal controller 24 acquires the first signal level in the prefix during the half-cycle period from falling to rising (the period from the detection time t2” of the first falling edge to the detection time t3” of the next rising edge). LOWThe clock signal is defined as half a cycle. Furthermore, the terminal controller 24 defines the period C of the first signal level in the prefix, from falling, rising and falling again, as one cycle of the clock signal (from the detection time t2” of the first falling edge to the detection time t4” of the falling edge that appears again after the rise) as one cycle of the clock signal.

[0144] Then, the terminal controller 24 determines the half-cycle period C of the prefix signal level. LOW After a period C is defined as the period of the clock signal, the detection time t4” of the falling edge at the end of a period that serves as a prefix is ​​set as the reference time t4”. The terminal controller 24 uses the half-period period C determined as the period of the clock signal to define the clock signal. LOW During a period of one cycle, the signal level is determined sequentially according to the following formula (3) with reference time t4” as the reference.

[0145] (nC+C LOW ) / twenty three)

[0146] In equation (3) above, n represents the number of bits of tag information read from the signal level. It should be noted that in this embodiment, n is used because the tag information consists of eight bits, and the number of reads from the signal level is eight; therefore, n = 8. In equation (3) above, C represents one period. LOW This indicates a half-cycle period.

[0147] At this time, the terminal controller 24 uses half a cycle period C, which is determined as the period of the clock signal. LOW And a period C, starting from the reference time t4”, sequentially in {(1C+C) LOW ) / 2} time tg1”、{(2C+C LOW ) / 2} time tg2”、{(3C+C LOW ) / 2} time tg3”、……、{(8C+C LOW The signal level is determined at time tg8.

[0148] In this way, the terminal controller 24 determines the signal level at times tg1”, tg2”, tg3”, etc., to obtain tag information of a preset data length (here, eight bits). This tag information acquisition process can achieve the same effect as the above-described implementation method.

[0149] Figure 14 Figures 1081, 1082, and 1083 illustrate how, for some reason, the timing of the signal level drop in the received data at the terminal (times t2", t4", etc.) is later than the time when the tag transmits the data. Figure 14 The waveforms at which the signal level drops during timing intervals (t2, t4, tg1, etc.) in (1082). Figure 141081 is a schematic diagram representing the clock signal waveform. Figure 14 The 1082 is a schematic diagram representing the tag data transmission generated according to the period of this clock signal. Figure 14 1083 represents a schematic diagram of terminal receiving data based on tag-transmitted wave generation.

[0150] Figure 14 In the terminal received data shown in 1083, for example, the falling time t2” of the first signal level in the prefix is ​​delayed by |t2-t2”| time compared to the falling time t2 of the first signal level in the prefix of the tag transmitted data, resulting in a corresponding offset.

[0151] Furthermore, the signal level rise timing (time t3”, etc.) in the terminal's received data is earlier than the signal level rise timing (times t3, t5, tg2, etc.) in the tag's transmitted data. This causes the rise time t3” of the first signal level in the prefix of the terminal's received data to occur only |t3”-t3| time earlier than the rise time t3 of the first signal level in the prefix of the tag's transmitted data, resulting in a corresponding offset.

[0152] At this time, the terminal controller 24 will still use the first signal level in the prefix for half a cycle from falling to rising (the period from the detection time t2” of the first falling edge to the detection time t3” of the next rising edge) C. LOW The clock signal is defined as half a cycle. Furthermore, the terminal controller 24 defines the period C of the first signal level in the prefix, from falling, rising and falling again, as one cycle of the clock signal (from the detection time t2” of the first falling edge to the detection time t4” of the falling edge that appears again after the rise) as one cycle of the clock signal.

[0153] Then, the terminal controller 24 determines the half-cycle period C of the prefix signal level. LOW After a period C is used as the clock signal period, the detection time t4” of the falling edge at the end of one period of the prefix is ​​set as the reference time t4”. The terminal controller 24 uses half a period C. LOW And a period C and based on the above equation (3), starting from the reference time t4”, sequentially in {(1C+C) LOW ) / 2} time tg1”、{(2C+C LOW ) / 2} time tg2”、{(3C+C LOW ) / 2} time tg3”、……、{(8C+C LOW The signal level is determined by tg8 at time ) / 2}.

[0154] In this way, the terminal controller 24 determines the signal level at specific times tg1”, tg2”, tg3”, etc., to obtain tag information of a preset data length (here, eight bits). This tag information acquisition process can achieve the same effect as the above-described implementation method.

[0155] It should be noted that, although in Figure 13 and Figure 14 The example describes the use of a prefix consisting of a falling period, a rising period, and a falling period, but the present invention is not limited thereto. As a means of obtaining tag information using the above formula (3), a prefix with opposite falling and rising configurations (a prefix consisting of a rising period, a falling period, and a rising period) can be used, for example. In this case, the half-cycle period C... LOW The period C is the rise-fall time of the first signal level in the prefix, and one cycle C is the rise-fall-rise time of the first signal level in the prefix. Prefixes of this type can achieve the same effect.

[0156] Explanation of reference numerals in the attached figures

[0157] 1: Wireless Tag

[0158] 2: Communication terminal

[0159] 11: Tag Antenna

[0160] 13: Clock signal generation circuit

[0161] 15: Tag Controller

[0162] 16: Modulation circuit

[0163] 21: Terminal Antenna

[0164] 22: Signal Processing Department

[0165] 24: Terminal Controller

Claims

1. A wireless tag, used to modulate tag transmission data containing tag information of a preset data length as a tag transmission wave and transmit it to a communication terminal, characterized in that, include: A clock signal generation circuit that generates a clock signal with a preset period; A tag controller assigns a prefix of a fixed signal pattern to the tag information to indicate the start of the tag information, and generates tag transmission data according to the period of the clock signal. The tag transmission data includes the prefix and the tag information with varying signal levels. A modulation circuit that modulates the tag transmission data generated by the tag controller to generate the tag transmission wave; as well as The tag antenna transmits the tag transmission wave to the communication terminal. By enabling the communication terminal to receive the tag transmission wave, the period of the clock signal generated by the clock signal generation circuit is determined for the communication terminal based on the rising and / or falling period of the signal level in the prefix, and the tag information is obtained based on the determined period of the clock signal.

2. The wireless tag according to claim 1, characterized in that, The prefix is ​​assigned before the label information.

3. The wireless tag according to claim 1, characterized in that, The prefix includes at least one of the following components: The signal level is configured to change in a falling, rising, and falling sequence; or The signal level is composed of changes in the order of rising, falling, and rising.

4. The wireless tag according to claim 1, characterized in that, The tag transmits data with a standby period preceding the prefix and the tag information. This standby period is longer than the data length of the tag information, and the rising or falling signal level is continuous.

5. The wireless tag according to claim 1, characterized in that, When a terminal transmission wave is received from the communication terminal, driving power is generated based on the terminal transmission wave, and the clock signal generation circuit, the tag controller, and the modulation circuit are activated by the driving power.

6. The wireless tag according to claim 1, characterized in that, When a terminal transmission wave is received from the communication terminal via the tag antenna, the tag transmission wave is generated based on the terminal transmission wave and transmitted to the communication terminal.

7. The wireless tag according to claim 1, characterized in that, For the communication terminal that receives the tag transmission wave, based on the tag transmission wave, The falling or rising period of the signal level in the prefix is ​​determined as half a cycle period. One of the periods of the signal level in the prefix, from falling to rising and then falling again, and the period of the signal level, from rising to falling and then rising again, is determined as a period. Using the half-cycle period and the full-cycle period that determine the period of the clock signal, the end time of the full-cycle is taken as the reference time, and the signal level is determined by the following formula (1) based on the reference time to obtain the tag information. (nC+C LOW ) / 2……(1) The n represents the number of bits of tag information read from the signal level. The C represents the duration of one period. LOW This indicates the period of the half-cycle.

8. A communication terminal, configured to receive a tag transmission wave transmitted from a wireless tag by modulating tag transmission data containing tag information of a preset data length, and demodulating the tag transmission wave to obtain the tag information, characterized in that, include: A terminal antenna assigns a prefix of a fixed signal pattern to the tag information, indicating the start of the tag information, and receives the tag transmission wave generated by modulating the tag transmission data from the wireless tag according to a clock signal of a preset period generated by the wireless tag. The tag transmission data includes the prefix and the tag information with varying signal levels. The signal processing unit demodulates the tag transmission wave to generate the tag transmission data; as well as A terminal controller determines the period of the clock signal generated by the wireless tag based on the rising and / or falling period of the signal level in the prefix included in the tag's transmitted data, and acquires the tag information based on the determined period of the clock signal.

9. The communication terminal according to claim 8, characterized in that, The prefix includes at least one of the following components: The signal level is configured to change in a falling, rising, and falling sequence; or The signal level is composed of changes in the order of rising, falling, and rising.

10. The communication terminal according to claim 8, characterized in that, The terminal controller is used for: The average value of the rising or falling periods of the signal level that appears more than twice in the prefix is ​​calculated, and the period of the clock signal generated by the wireless tag is determined based on the calculated average value.

11. The communication terminal according to claim 8, characterized in that, The terminal controller is used for: The tag information is obtained by detecting the rising and falling signal levels following the last signal level of the prefix based on the period of the clock signal detected by the prefix.

12. The communication terminal according to claim 8, characterized in that, The terminal controller is used for: The falling or rising period of the signal level in the prefix is ​​determined as half a cycle period. One of the periods in the prefix, from the signal level falling, rising, and falling again, and from the signal level rising, falling, and rising again, is determined as a period. Using the half-cycle period and the full-cycle period that determine the period of the clock signal, the end time of the full-cycle is taken as the reference time, and the signal level is determined by the following formula (2) based on the reference time to obtain the tag information. (nC+C LOW ) / 2……(2) The n represents the number of bits of tag information read from the signal level. The C represents the duration of one period. LOW This indicates the period of the half-cycle.

13. A communication system comprising a wireless tag and a communication terminal, wherein the wireless tag modulates tag transmission data containing tag information of a preset data length to transmit as a tag transmission wave, and the communication terminal receives the tag transmission wave transmitted from the wireless tag and demodulates the tag transmission wave to obtain the tag information, characterized in that... The wireless tag includes: A clock signal generation circuit that generates a clock signal with a preset period; A tag controller assigns a prefix of a fixed signal pattern to the tag information to indicate the start of the tag information, and generates tag transmission data according to the period of the clock signal. The tag transmission data includes the prefix and the tag information with varying signal levels. A modulation circuit that modulates the tag transmission data generated by the tag controller to generate the tag transmission wave; as well as The tag antenna transmits the tag's transmitted waves to the communication terminal. The communication terminal includes: A terminal antenna that receives the tag-transmitted wave transmitted from the wireless tag; A signal processing unit demodulates the tag transmission waveform to generate the tag transmission data; and A terminal controller determines the period of the clock signal generated by the wireless tag based on the rising and / or falling period of the signal level in the prefix included in the tag's transmitted data, and acquires the tag information based on the determined period of the clock signal.

14. A communication method between a wireless tag and a communication terminal, wherein the wireless tag modulates tag transmission data containing tag information of a preset data length as a tag transmission wave and transmits it, and the communication terminal receives the tag transmission wave transmitted from the wireless tag and demodulates the tag transmission wave to obtain the tag information, characterized in that... The wireless tag performs the following steps: The clock signal generation step involves generating a clock signal with a preset period through a clock signal generation circuit. The tag transmission data generation step involves assigning a prefix of a fixed signal pattern indicating the start of the tag information to the tag information, and generating the tag transmission data through a tag controller according to the period of the clock signal. The tag transmission data includes the prefix and the tag information with varying signal levels. The modulation step involves modulating the tag transmission data generated by the tag controller using a modulation circuit to generate the tag transmission wave. as well as The transmission step involves sending the tag transmission wave from the tag antenna to the communication terminal. The communication terminal performs the following steps: The receiving step involves receiving the tag-transmitted wave from the wireless tag via the terminal antenna; The demodulation step involves demodulating the tag's transmitted waveform to generate the tag's transmitted data via a signal processing unit. as well as The acquisition step involves using a terminal controller to determine the period of the clock signal generated by the wireless tag based on the rising and / or falling period of the signal level in the prefix contained in the tag's transmitted data, and acquiring the tag information based on the determined period of the clock signal.

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