WO2004053784A1

WO2004053784A1 - An electronic label system on a shelf and an electronic label thereof

Info

Publication number: WO2004053784A1
Application number: PCT/CN2003/001008
Authority: WO
Inventors: Wei Chen; Xue Fang Wu
Original assignee: Wei Chen; Xue Fang Wu
Priority date: 2002-12-10
Filing date: 2003-11-27
Publication date: 2004-06-24
Also published as: CN1506900A; AU2003289597A1; CN1224933C

Abstract

This invention refers to an electronic label system on a shelf and an electronic label thereof. The main controller in the system of this invention, transmits a low-frequency radio wave, which is used as a carrier wave for digital signals, to the corresponding electronic label. What is the most significant in this invention is that there is a software instead of a demodulator circuit, which brings large power consumption and high cost. What is more, the software could make use of the program instructions in the microprocessor to sample signals at a scheduled time and to demodulate digital signals directly from radio wave, and further to store and display the data after decoding and other process. It is advantageous in the system that it is reliable and easy to use, and moreover, it brings low cost and low power consumption with a simple structure.

Description

Electronic shelf label system and electronic label

The invention relates to a shelf label system and a label thereof. Background technique

In shopping malls, warehouses, etc., paper labels are usually used to display product prices, specifications, inventory, and / or promotional signs. However, when data is to be updated, the workload is large and error-prone, which is not suitable for modern scientific management. As an improvement, an electronic shelf label system using an electronic label instead of a paper label has appeared. The electronic shelf label system includes multiple electronic labels with display devices. Usually it is installed on the shelf to replace the original paper label. It can solve the problem of product price. It can be remotely controlled by the computer to change the price without any need. Manual operation. On the same database platform, system hosts, cash registers, and electronic labels can always maintain price consistency, and dynamic pricing and promotion information can be conveniently displayed, bringing a whole new world to price management.

In the early stage of the development of electronic shelf labeling systems, wired products were used first. Each electronic label provided power and transmitted information through cables. Such products are very inconvenient to use. They have been gradually phased out, and only a few are used in Warehouse shelves. Later, electronic shelf label systems that used radio and microwave (usually 2.4GHz) to transmit information, such as the US patent US6108367, etc., have greatly improved performance and ease of use. This type of product often uses a two-way transmission method, that is, each electronic tag can send a confirmation signal to the system after receiving the information, which improves reliability. The current problems are: the system needs to install antennas near each shelf, the 2.4GHz frequency is easy to interfere with the existing communication system, and its structure is also more complicated and the cost is higher. There are also electronic shelf label systems that use low-frequency radio waves to transmit information. For example, the electronic shelf label system disclosed in US Patent No. 5,504,475 uses low-frequency radio waves, although in theory, low-frequency radio waves largely avoid interference problems. Reliability and security have also been improved, but according to the patentee's description in the invention, the invention is characterized by a method that uses external instructions to adjust the sampling time interval, so that the receiving circuit is often in a non-working state to reduce Power consumption. However, there is a problem because each electronic tag in the system needs a receiving circuit with a demodulation function to extract the digital baseband signal in the radio wave (called demodulation). The existence of the receiving circuit makes the electronic tag's Both cost and power consumption are relatively large. Summary of the Invention

An object of the present invention is to provide an electronic shelf label system with simple structure, low cost, reliable operation, convenient use, and low power consumption, and an electronic label thereof. The general technical idea of the present invention is: use low-frequency radio waves as the carrier of digital signals, remove the hardware demodulation circuit with large power consumption in the electronic tag, and use software to pass program instructions in the microprocessor in accordance with the timing The method uses the signal to demodulate and extract digital information directly from the radio waves, and then performs processing such as decoding to realize the functions of saving and displaying data.

The technical solution for providing an electronic tag with simple structure, low cost, reliable operation, convenient use, and low power consumption in achieving the purpose of the present invention is: The electronic tag has a casing, a circuit device, and a display screen, and the circuit device is disposed in the casing. The display screen is arranged on the casing and is located at the display window of the casing; the circuit device has an antenna device, a microprocessor, a main crystal circuit and a DC power terminal; the microprocessor is provided with a power terminal, a main crystal terminal, a display output terminal and a signal Input port; The power terminal of the microprocessor is in line with the DC power terminal of the circuit device; the main crystal terminal of the microprocessor is connected to the main crystal circuit; the display output terminal of the microprocessor is connected to the display screen or the driving circuit and the display screen It is characterized in that: the output end of the antenna device is connected to the signal input port of the microprocessor; the microprocessor is a microprocessor having a function of processing digitally modulated low-frequency radio wave signals through a software program, and can process low-frequency signals Frequency in

4kHz to 200kHz.

The signal input port of the microprocessor is a port with a signal amplification function, or the circuit device also has a preamplifier circuit or a bias circuit; the preamplifier circuit or the bias circuit is provided at the output end of the antenna device and the signal of the microprocessor Between input ports. The microprocessor also has a sampling signal output port; the sampling signal output port is connected to the enable terminal of the pre-amplification circuit or the bias circuit.

The above circuit device also has a secondary crystal oscillator circuit, and the microprocessor also has a secondary crystal oscillator terminal, and the secondary crystal oscillator circuit is connected to the secondary crystal oscillator terminal of the microprocessor. The oscillation frequency of the secondary crystal circuit is between 20 kHz and 100 kHz, and the oscillation frequency of the main crystal circuit 25 is between 400 kHz and 40 MHz.

This label also has a DC power supply. The output end of the DC power supply is connected to the power supply end of the circuit device.

The process for the microprocessor of the above circuit device to process the digitally modulated low frequency radio wave signal through a software program is: ① judging whether there is a signal input according to the level change of the signal input port; ② comparing the change of the time parameter of the signal waveform to Determine whether there is a signal node; ③ Measure the symbol length between adjacent signal nodes and store it in the data memory. The collection of this series of symbol lengths forms a data column representing the baseband signal, thereby achieving software solution. Tuning function; ④ Decode the baseband signal into actual data frames, and complete the software decoding process; ⑤ Analyze and process the received data, then control the working state of the microprocessor, and display relevant information through the display screen.

The technical solution of providing an electronic shelf label system with simple structure, low cost, reliable work, convenient use, and low power consumption for achieving the purpose of the present invention is: The system has a main controller and multiple electronic labels; the main controller has Computer, exciter and loop antenna; the exciter is connected to the computer through its communication interface; the exciter is connected to the loop antenna by its driver and resonant capacitor; the exciter has the information transmitted by the computer driven by encoding and modulation The function that the loop antenna sends to the space; The electronic label is placed in the range surrounded by the loop antenna, and can receive the information sent by the main controller and display specific information; the electronic label has a housing, a circuit device and a display screen. The circuit device is disposed in the casing, and the display screen is disposed on the casing and located at the display window of the casing; the circuit device has an antenna device, a microprocessor, a main crystal circuit and a DC power terminal; the microprocessor is provided with a power terminal and a main crystal terminal Display output terminal and signal input port; the power supply terminal of the microprocessor is in line with the DC power supply terminal of the circuit device; the main crystal terminal of the microprocessor is connected to the main crystal circuit; the display output terminal of the microprocessor is connected to the display or The driving circuit is connected to the display screen; It is characterized in that: the output end of the antenna device is connected to the signal input port of the microprocessor; the microprocessor is a microprocessor with a function of processing digitally modulated low-frequency radio wave signals through a software program, It can process low-frequency signals between 4kHz and 200kHz. The process of the microprocessor processing low-frequency radio wave signals through a software program is: ① judging whether there is a signal input according to the level change of the signal input port; ② judging whether there is a signal node by comparing changes in the time parameter of the signal waveform; ③ measurement The symbol length between adjacent signal nodes is obtained, and each symbol length is stored in a corresponding unit of the data memory. This set of symbol lengths forms a data column representing the characteristics of the baseband signal parameter, thereby achieving Software demodulation function; ④ decode the baseband signal into the actual received data frame, and complete the software decoding process; ⑤ analyze and process the received data, then control the working state of the microprocessor, and display relevant information through the display screen come out.

The present invention has positive effects: (1) The electronic shelf label system of the present invention uses a low-frequency radio wave as a signal carrier, because its frequency range is far from the existing commercial communication frequency band, and its emission range is basically limited to a specific space. Therefore, the mutual interference between this system and the existing communication system is small, so the reliability is relatively high and the security is good. ( ₂ ) The electronic tag of the present invention uses a software program to demodulate the received digitally modulated low-frequency radio wave signal, thus eliminating the hardware demodulation circuit with large power consumption in the prior art. Low and simple structure, low cost. (3) The three commonly used digital modulation methods (ASK, PSK, FSK) can be applied to the electronic shelf label system of the present invention, so the application of the present invention is wide. In the specific implementation process, the corresponding modulation mode needs to be selected from the bit error rate, transmission efficiency, implementation cost, and characteristics of the specific microprocessor 24 used. (4) When the electronic tag of the present invention is provided with a pre-amplification circuit or a bias circuit in the circuit device, the receiving sensitivity can be improved; if a timing sampling function is set on this basis, this can effectively suppress the receiving sensitivity while suppressing it. Increased power consumption. (5) When the microprocessor in the electronic tag of the present invention operates with a dual crystal oscillator, the standby power consumption of the tag in a no-signal state can be greatly reduced. (6) The electronic shelf label system of the present invention is widely used in retail stores and warehouse management systems, and can improve the modern scientific management level. BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of an electronic tag according to the present invention. FIG. 2 is a schematic top view of FIG. 1.

3A to 3J are schematic block diagrams of the electrical principle of the electronic tag of the present invention. Among them: Fig. 3A is an electrical schematic diagram with a relatively simple structure. FIG. 3B is an electrical schematic diagram after a bias circuit is provided on the basis of FIG. 3A. FIG. 3C is an electrical schematic diagram after the sampling signal output port is set on the microprocessor based on FIG. 3B. FIG. 3D is an electrical schematic diagram after a pre-amplification circuit is provided on the basis of FIG. 3A. FIG. 3E is an electrical schematic diagram after the sampling signal output port is set on the microprocessor based on FIG. 3D. FIG. 3F is an electrical schematic diagram of a secondary crystal circuit provided on the basis of FIG. 3A. FIG. 3G is an electrical schematic diagram of a sub-crystal oscillator circuit based on FIG. 3B. FIG. 3H is an electrical schematic diagram of a secondary crystal circuit provided on the basis of FIG. 3C. FIG. 31 is an electrical schematic diagram of a secondary crystal circuit provided on the basis of FIG. 3D. FIG. 3J is an electrical schematic diagram of a sub-crystal oscillator circuit based on FIG. 3E.

FIG. 4 is a schematic block diagram of the internal structure of the microprocessor in FIGS. 3H and 3J.

FIG. 5 is a schematic structural diagram of an electronic shelf label system according to the present invention.

FIG. 6 is a circuit block diagram of the main controller in FIG. 5.

FIG. 7 is a schematic diagram of a signal flow when the electronic shelf label system of the present invention performs data transmission and reception. Among them, FIG. 7A shows the transmission data frame sent by the main controller; FIG. 7B shows the baseband signal encoded by the encoder; FIG. 7C shows the modulated signal modulated by the modulator, and also shows that the receiving antenna group is input to the microprocessor signal input port Figure 7D shows the pulse signal that the microprocessor converts the modulation signal from the microprocessor signal input port and reads it into the internal bus; Figure 7E shows the virtual baseband obtained after processing by the microprocessor demodulation program The signal is a data column representing the characteristics of the baseband signal parameter; FIG. 7F shows the received data frame obtained after processing by the microprocessor decoding program.

FIG. 8 is a waveform diagram of signal nodes in FIG. 7C and FIG. 7D in the PSK mode. Among them, Fig. 8A shows the modulation signal corresponding to Fig. 7C; Fig. 8B shows the pulse signal corresponding to Fig. 7D entering the internal bus of the microprocessor.

FIG. 9 is a waveform diagram of signal nodes in FIG. 7C and FIG. 7D in the FSK mode. Among them, FIG. 9A shows a modulation signal corresponding to FIG. 7C; FIG. 9B shows a pulse signal corresponding to FIG. 7D entering the internal bus of the microprocessor.

FIG. 10 is a waveform diagram of signal nodes in FIGS. 7C and 7D in the ASK mode. Among them, FIG. 10A1 and FIG. 10B1 respectively show modulation signals and pulse signals generated when the signal amplitude suddenly decreases for a short period of time at the signal node, and then the amplitude recovers rapidly; FIG. 10A2 and FIG. 10B2 respectively show the signal node Where the signal amplitude suddenly becomes large for a short period of time, and then the amplitude is rapidly restored. Figure 10A3 and Figure 10B3 show that the signal amplitude suddenly decreases at the signal node and continues to the next signal. Modulation signal and pulse signal generated when the node recovers.

FIG. 11 is a program block diagram of a microprocessor in an electronic tag according to the present invention. detailed description

(Example 1, electronic tag)

As shown in Figs. 1 to 3A, the electronic tag 100 of this embodiment has a casing 1, a circuit device 2, a display screen 3, and a power source 4. The circuit device 2 is disposed in the casing 1, and the display screen 3 is disposed on the casing 1 and located at a display window of the casing 1. The circuit device 2 has an antenna device 21, a microprocessor 24, a main crystal circuit 25, and a DC power supply terminal; micro-processing The device 24 is provided with a power terminal, a main crystal terminal 24-13, a display output terminal 24-15, and a signal input port 24-1; the power terminal of the microprocessor 24 and the DC power terminal of the circuit device 2 are co-linear; the microprocessor 24 The main crystal terminal 24-13 is connected to the main crystal circuit 25; the display output terminal 24-15 of the microprocessor 24 is connected to the display 屛 3; the output terminal of the antenna device 21 is connected to the signal input port 24-1 of the microprocessor 24 The microprocessor 24 is a microprocessor having a function of processing a digitally modulated low frequency radio wave signal by a software program, and can process a low frequency signal frequency of 40 kHz and a main crystal frequency of 4 MHz.

The casing 1 is made of plastic pellets, and may be a paper casing in other embodiments. The dotted frame in FIG. 2 indicates the circuit device 2 in which the electronic tag 100 is provided.

The antenna device 21 of the circuit device 2 comprises an antenna L and a resonance capacitor C1 in parallel to form a resonance circuit to obtain a higher resonance voltage. The receiving antenna L is a multi-turn coil. The coil is usually wound with enameled wire. In order to improve the reception effect, the coil is usually wound on a ferrite magnet. The frequency of the main crystal in the main crystal circuit 25 is selected to be 4 MHz. The display screen 3 is an LCD liquid crystal display screen (in other embodiments, a light emitting diode LED display or another type of display can also be used). The power source is a 3 V lithium-manganese dioxide battery (in other embodiments, solar cells or other DC power supply devices can be used).

Referring to FIG. 4, the microprocessor 24 of the circuit device 2 is a general-purpose digital chip (also referred to as a single-chip microcomputer). There are at least one external data input port 24-1 (that is, the above-mentioned signal input port 24-1), a central processing unit 24-3 with an interrupt processing function, an ALU arithmetic logic unit 24-4, and a display driving circuit 24-5 , At least two timers (first timer 24-6 and second timer 24-7), program memory 24-8, data memory 24-9, clock generator 24-10 (driven by main crystal oscillator circuit 25) Wait. The display driving circuit 24-5 is built in by the microprocessor 24 (in other embodiments, it may be externally installed). In other embodiments, the signal input port 24-1 may be a port having a signal amplification function. In this embodiment, the microprocessor 24 may be EM73461A, EM73P461A, EM73461B, EM73469A, EM73866, EM73880, EM73983, EM73P968, or EM73C63 in the EM series of single-chip microcomputers from ELAN, Taiwan, or Winbond of Taiwan. The W741E260, W541E260, W741C260 or W741C260 of the company's W741 or W541 series microcontrollers, or the TMP47C620 / 820 of the TMP series microcontrollers of Toshiba Japan, or the 753012A, 753016A of the 75XL series microcontrollers of Eimoto NEC Company , 753017A, 75P3018A, 75P3116, 753104, 753106 or 753108, Or S3C7238 / C7235, S3C72C8, S3C72H8 or S3C72K8 / P72K8 in the S3C7 (KS57) series of single-chip microcomputers from Samsung (SAMSUNG).

The structure of the electronic tag 100 of this embodiment is very simple. The receiving antenna L receives a low-frequency radio digital modulation signal of a corresponding frequency, and the modulation signal is directly input into the microprocessor 24 through the signal input port 24-1 by the output end of the antenna device 21; the microprocessor 24 through the signal input port 24-1 The modulation signal is converted into a pulse signal and input to the internal bus 24-11, and then the received signal is demodulated and decoded by the program processing function of the microprocessor 24 itself, and the LCD display 3 is driven to display.

(Example 2, electronic tag)

As shown in FIG. 3B, the rest is the same as that of Embodiment 1, except that a bias circuit 23 is further provided between the output end of the antenna device 21 and the signal input port 24-1 of the microprocessor 24. The bias circuit 23 is composed of voltage-dividing resistors R1, R2 and a DC blocking capacitor C2. The function of the bias circuit 23 is to set the center point of the input signal near the threshold of the signal input port 24-1, thereby improving the circuit device 2. Receive sensitivity. In other embodiments, the bias circuit 23 may be integrated inside the microprocessor 24.

(Example 3, electronic tag)

See FIG. 3C and FIG. 4, the rest are the same as those in the second embodiment, except that the microprocessor 24 is further provided with a sampling signal output port 24-2, and one end of the resistor R2 of the bias circuit 23 is provided by the second embodiment. It is connected to the low level to be connected to the sampling signal output port 24-2 of the microprocessor 24, and becomes an enable terminal of the bias circuit. This setting causes the bias circuit 23 to change from being always in the working state to being in the gap working state (the gap time can be set to 5-10 seconds) in the second embodiment, thereby reducing the power consumption of the electronic tag 100. The bias circuit 23 may change from a non-working state to a working state when the high-level signal sent to the enable terminal thereof by the usual receiving microprocessor 24 is changed to the receiving low-level signal.

(Example 4, electronic tag)

As shown in FIG. 3D, the rest is the same as that of Embodiment 2, except that the preamplifier circuit 22 is used instead of the bias circuit 23, which also improves the receiving sensitivity. The preamplifier circuit 22 is an amplifier circuit composed of an integrated operational amplifier or discrete components. In other embodiments, the pre-amplification circuit 22 may be integrated inside the microprocessor 24.

(Example 5, electronic tag)

See FIG. 3E and FIG. 4, the rest is the same as the embodiment 4, except that the microprocessor 24 is further provided with a sampling signal output port 24-2. The sampling signal output port 24-2 is connected to the enable terminal of the pre-amplification circuit 22. The role of the sample signal output port 24-2 is to sample signals (which can be low, high or The edge trigger signal determines the type of the sampling signal according to the characteristics of the specific amplifier circuit) and outputs it to the enable end of the preamplifier circuit 22 to control whether the preamplifier circuit 22 is in a working state, thereby reducing the power consumption of the electronic tag 100. (Examples 6 to 10, electronic tags)

3F to FIG. 3L to FIG. 3F. The embodiment 6 shown in FIG. 3F corresponds to the embodiment 1. The embodiment 7 shown in FIG. 3G corresponds to the embodiment 2. The embodiment 8 shown in FIG. 3H corresponds to the embodiment 3. Correspondingly, the embodiment 9 shown in FIG. 31 corresponds to the embodiment 4, and the embodiment 10 shown in FIG. 3J corresponds to the embodiment 5. The rest of the embodiments from the embodiment 6 to the embodiment 10 correspond to The embodiments are the same, except that the electronic tag 100 further includes a secondary crystal oscillator circuit 26, the microprocessor 24 also has a secondary crystal oscillator terminal 24-14, and the secondary crystal circuit 26 is connected to the secondary crystal oscillator terminals 24-14 of the microprocessor 24. The sub crystal in the sub crystal circuit 26 is usually 32.768 kHz.

As shown in FIG. 4, the microprocessor 24 in the eighth embodiment and the tenth embodiment adopts a microprocessor having the structure shown in FIG. The internal clock generator 24-10 of the microprocessor 24 can be driven by the sub crystal (usually 32.768 kHz) in the sub crystal circuit 26 at the same time, so that the power saving performance is improved. The reason is: the microprocessor 24 can work at two clock frequencies, where the secondary crystal is always in the working state, and the main crystal is only in the working state when receiving and processing valid signals. When the main crystal oscillator operates, the microprocessor 24 has a higher processing speed because the main crystal oscillator generates a high-frequency clock signal, which can be used for complex data processing, but the power consumption is also large. When not receiving a signal, often only the secondary crystal provides a low-frequency clock signal, and the main crystal does not work. At this time, the microprocessor 24 has a low processing speed, and usually only performs the driving and signal sampling of the LCD liquid crystal display 3. Such a situation occupies most of the entire use process of the electronic tag 100, so that low power consumption can be realized.

(Example 11, electronic shelf label system)

As shown in FIGS. 5 and 6, the electronic shelf label system of this embodiment includes a main controller 5 and a plurality of electronic labels 100. The main controller 5 includes a computer 51, an exciter 52, and a loop antenna 53. The exciter 52 has a communication interface 52-1, an encoder 52-2, a modulator 52-3, a driver 52-4, a resonance capacitor 52-5, a signal generator 52-6, and a power supply 52-7. The exciter 52 is connected to the computer 51 through its communication interface 52-1. The exciter 52 is connected to the loop antenna 53 by its driver 52-4 and a resonance capacitor 52-5; the exciter 52 has a function of encoding and modulating the information transmitted by the computer 51 to drive the loop antenna 53 and send it to space. The loop antenna 53 is constituted by a wire that can be surrounded on the ceiling or wall of a shopping mall using the system of the present invention. Most of the radio signals sent from the main controller 5 will be concentrated in the range of the shopping mall surrounded by the loop antenna 53. The electronic tag 100 obtained in the foregoing Embodiment 8 or Embodiment 10 (the electronic tags obtained in Embodiments 1 to 7 and Embodiment 9 may also be used in other embodiments) are placed in the range surrounded by the loop antenna 53. Here, The electronic tag 100 within the range can receive the information sent by the main controller 5, and display specific information-commodity prices, etc.-. For selecting the resistance values of the resistors R1 and R2 of the bias circuit 23 in the electronic tag 100, when the enable terminal of the bias circuit 23 is connected to a low level, the level value of the center point of the modulation signal is at a micro level. The signal input of the processor 24 is near the threshold of the port 24-1.

The computer 51 is usually used by shopping malls to manage cash registers, scanners and other equipment. It will represent the number of product information The frame signal is transmitted to the exciter 52. The communication interface 52-1 uses a wired serial interface RS232C interface in this embodiment (in other embodiments, an Ethernet interface or a wireless transceiver port can be used).

The frequency f (hereinafter referred to as the system operating frequency f) of the low-frequency electromagnetic wave carrier signal emitted by the signal generator 52-6 in the exciter 52 is 40 kHz in this embodiment, and the system operating frequency f may be between 4 kHz and Select within a 200kHz range. As shown in FIG. 7, the data frame shown in FIG. 7A received by the computer 51 and received via the communication interface 52-1 usually includes the address code ID of the electronic tag 100, the commodity price, the display mode instruction, the work status instruction, and the check code. Wait. The encoder 52-2 encodes the baseband signal as shown in FIG. 7B according to a certain rule. The baseband signal usually has two parts, a start bit and a data bit. The baseband signal is composed of high-level H and low-level L alternately. The duration of a high-level H or low-level L is referred to herein as the symbol length 62. In order to reliably modulate and demodulate, each symbol length 62 cannot be too small, usually greater than 30 / f (f refers to Is the operating frequency of the system). The modulator 52-3 modulates the baseband signal on the sine wave signal sent from the signal generator 52-6 to form a modulation signal as shown in FIG. 7C, and then amplifies the power of the signal through the driver 52-4. The driver 52-4 drives the loop antenna 53 which is resonant in series with the resonance capacitor 52-5 to transmit the electromagnetic wave of the modulated signal to the shopping mall space. Here, the resonance capacitor 52-5 is in series resonance with the loop antenna 53 having an inductive characteristic, so that the current on the loop antenna 53 is strengthened, and the electromagnetic wave energy of the modulated signal can be fully transmitted. The loop antenna 53 and the antenna L of the antenna device 21 of the electronic tag 100 are coupled in space.

The modulation method of the modulator 52-3 in the exciter 52 is digital modulation. In this embodiment, a conventional phase shift keying PSK modulation method is used (in other embodiments, the three conventional digital modulation methods can also be used. Frequency-shift-keyed FSK or amplitude-keyed AS modulation, or a combination of three conventional digital modulation methods or a combination of any two). See FIG. 7B and FIG. 7C. For a baseband signal, at the signal node 61, the baseband signal level is changed. When the modulator 52-3 modulates, the waveform parameters of the sine wave (carrier signal) are changed at the signal node 61. To reverse its phase. The 电子 processor 24 of the electronic tag 100 (also referred to as a single-chip microcomputer in some places, see FIG. 4) converts the modulation signal shown in FIG. 8A into a pulse signal shown in FIG. 8B through the signal input port 24-1, and then inputs it to the internal bus 24 -11 on. Because the microprocessor 24 can analyze the pulse signal with a program, it can only make a decision on the time-related parameters of the pulse signal, so the time parameter of the pulse signal at the signal node 61 shown in FIG. 8B has a significant change, which makes the demodulation Made it happen.

See FIG. 11 and FIG. 4. The working process of the electronic tag 100 in this embodiment is given by the flowchart of FIG. 11: Step 71: Apply working power 4 to each relevant part of the electronic tag 100, including the microprocessor 24 in The internal components are powered on and the microprocessor 24 is reset.

Step 72: The main crystal oscillator circuit 25 and the sub crystal oscillator circuit 26 are started by the microprocessor 24, and then program initialization is performed. Step 73: Stop the main crystal oscillator circuit 25, and the microprocessor 24 enters a power saving state.

Step 74: The sampling signal output port 24-2 of the microprocessor 24 outputs a high level, and the first timer 24-6 is started. The timing length can be set to about 5 seconds, and the timing of the first timer 24-6 is reached. The sampling signal output port 24-2 outputs a low level to the enable terminal of the bias circuit 23, so that the level of the output terminal of the bias circuit 23 is at the signal input port 24-1 of the microprocessor 24 when there is no signal input. Near the threshold, when a signal is input, the center point of the signal is near the threshold of the signal input port 24-1 of the microprocessor 24.

Step 75: Detect whether there is a signal input that may be related to the modulation signal at the signal input port 24-1. The method is: start the second timer 24-7, the timing length must be greater than the maximum value of the symbol length 62, a more appropriate timing length is about three times the maximum value of the symbol length 62; within this timing length, repeatedly Read the value (0 or 1) of the signal input port 24-1 and determine whether there is a change. If there is a change, it is regarded as a signal input on the signal input port 24-1. If there is no change, it is regarded as a signal input port 24-1. signal input. If there is no signal input at signal input port 24-1, go to step 74; if there is signal input at signal input port 24-1, go to step 76.

Step 76: At this time, the sampling phase has ended and the signal processing phase is entered. The microprocessor 24 starts the main crystal circuit 25, and the microprocessor 24 enters a high-speed operation state.

Step 77: Detect whether the signal input from the signal input port 24-1 has a signal node 61. Because the microprocessor 24 can only discern significant time-related parameter changes, these parameters include frequency, period, and pulse width. A more suitable measurement parameter is the period. For convenience, the periods of any two adjacent pulse waveforms in FIG. 8B are defined as T1 and T2. Comparing the periods T1 and T2 of two adjacent pulses, when I T1-T2 | is greater than a certain value △ T, it is considered that a signal node 61 has occurred, otherwise it is considered that there is no signal node 61. The selection of ΔΤ is related to the modulation method, system frequency f, signal strength, use environment, and component parameters of each part of the electronic tag 100. The ΔΤ selection in this embodiment is 1 / 4f. In the actual situation, the modulation signal at signal node 61 is in a transition process, the waveform is irregularly distorted, and the parameters of the pulse signal are also complicated. Such a change process will last for several cycles, so a simple judgment is actually made A relatively high bit error rate will be generated. At this time, it is necessary to compare the change between T1 and T2 several times, and compare the sum of the absolute values with ΔΤ. If the accumulated value is greater than ΔΤ, it is judged that a signal node appears. 61, otherwise it is considered that there is no signal node 61 to ensure a lower bit error rate of the system. In this embodiment, the above two conditions for judging whether a signal node appears are used at the same time. As long as one of the conditions is satisfied, the signal node 61 is considered to be present, and the process proceeds to the next step 78-2, otherwise, the process proceeds to step 78-1. It can be known from FIG. 8B that the pulse signal has a signal node 61 at the second T2 shown in the figure.

The first timer 24-6 can be restarted on the rising or falling edge of the pulse signal, and at the same time, the previously obtained timing data T1 or T2 is stored in the corresponding address unit of the data memory 24-9, so that Compare the timing data. Set the signal input port 24-1 as an edge-triggered external signal interrupt source. The rising or falling edge of the number can be captured by interrupt processing.

Step 78-1: In the same way as in step 75, detect whether there is a signal input that may be related to the modulation signal at the signal input port 24-1. If yes, the program proceeds to step 77; if not, the program proceeds to step 73.

Step 78-2: If step 78-2 is performed for the first time, start the second timer 24-7. If step 78-2 is not performed for the first time, store the length of the second timer 24-7 in sequence. The corresponding cell group RAMn (n is a positive integer) in the data memory 24-9, and this timing length is approximately equal to the corresponding symbol length 62. The second timer 24-9 restarts.

Step 79: After performing step 77 and step 78-2 in a loop multiple times, the RAMI, RAM2, RAM3, and ~ RAMn groups of RAM in the data memory RAM have already stored data representing the symbol length 62 shown in FIG. 7E to form A series of data, which can be called a virtual baseband signal, can be decoded after a complete frame of data is obtained. The decoding process is a reverse process that follows the same rules as the encoder 52-2. After executing the decoding program, the received data frame shown in FIG. 7F is exactly the same as the transmitted data frame shown in FIG. 7A and stored in the data memory. 24-9 corresponding units.

Step 80: If a complete received data frame has been received, the address code ID, commodity price, display mode instruction, working status instruction, and check code included in the received data frame can be analyzed and processed to control the LCD liquid crystal. The display state and content of the display screen 3 and the operating state of the control microprocessor 24. Immediately return to step 77 to run the program cyclically.

There are certain requirements for the execution time of steps 78-2, 79, and 80. It is required that after the execution of step 80, the detection of the next signal node 61 in step 77 cannot be delayed; otherwise, if cost and power consumption are considered, micro processing The operating speed of the router 24 is indeed not fast. Therefore, it is necessary to process step 77 as an interrupt handler, that is, in the process of steps 78-2, 79, and 80, it is also determined whether the signal node 61 exists or not. It should be noted that it may be detected as multiple signal nodes 61 at one signal node 61. In this case, it is necessary to reset and start the first timer 24-6 every time the signal node 61 is detected. The length can be set to about half of the minimum symbol length 62. It is only after the timing of the first timer 24-6 that the next signal node 61 is detected.

In other embodiments, if the electronic tag 100 does not have the sub crystal oscillator circuit 26, step 73 and step 76 in the above procedure are omitted. If the microprocessor 24 of the electronic tag 100 is not provided with the sample signal output port 24-2, step 74 in the above procedure is omitted. If neither the secondary crystal circuit 26 nor the microprocessor 24 is provided with the sampling signal output port 24-2, steps 73, 74, 76 and 78-1 in the above-mentioned program are omitted; when the program runs to step 77, The non-signal contact 61 runs step 75. If the electronic tag 100 is not provided with the bias circuit 23, step 74 in the above procedure is omitted, and the signal center point is lower than the threshold of the signal input port 24-1, so that the amplitude of the received modulation signal is required to be large. (Example 12, electronic shelf label system)

The rest is the same as the embodiment 11, except that the modulation method of the modulator 52-3 in the exciter 52 is a conventional frequency shift keying FS modulation method. FIG. 9 shows the electronic tag 100 receiving modulation in the FSK mode. The signal time corresponds to the waveform diagram at the signal node in the modulated signal of FIG. 7C and the pulse signal of FIG. 7D. Among them, Fig. 9A shows the modulation signal entering the microprocessor's 24 signal input port 24-1; Fig. 9B shows the pulse signal entering the microprocessor's internal bus 24-11. It can be known from FIG. 9B that the pulse signal has a signal node 61 at the second T1 shown in the figure. The FSK modulation signal has two frequency quantities fl = f-Af and G = f + Af; if Af / f is too large, the antenna is not easy to tune, and if it is too small, it is difficult to demodulate. It is more suitable for about 8%. '

(Example 13: Electronic shelf label system)

The rest is the same as the embodiment 11, except that the modulation method of the modulator 52-3 in the exciter 52 is a conventional amplitude-keyed ASK modulation method. FIG. 10 shows the electronic tag 100 receiving the modulation signal in the ASK mode. This time corresponds to the waveform diagram at the signal node in the modulation signal of FIG. 7C and the pulse signal of FIG. 7D. Among them, FIG. 10A1 and FIG. 10B1 respectively show a modulation signal and a pulse signal generated when the signal amplitude suddenly decreases for a short period of time at the signal node 61, and then the amplitude recovers rapidly. It can be seen from FIG. 10B1 that the pulse signal has a signal node 61 at the second T2 shown in the figure.

(Example 14: Electronic shelf label system)

The rest is the same as Embodiment 13, except that FIG. 10A2 and FIG. 10B2 respectively show the modulation signal and the pulse signal generated when the signal amplitude suddenly increases for a short period of time at the signal node, and then the amplitude recovers rapidly. It can be seen from FIG. 10B2 that the pulse signal has a signal node 61 at the first T2 shown in the figure.

(Example 15: Electronic shelf label system)

The rest is the same as Embodiment 13, except that FIG. 10A3 and FIG. 10B3 respectively show the modulation signal and pulse signal generated when the signal amplitude suddenly decreases at the signal node and continues to be recovered at the next signal node. It can be known from FIG. 10B3 that the pulse signal has a signal node 61 at the beginning of the second T2 shown in the figure.

In the thirteenth embodiment to the fifteenth embodiment, the method for selecting the resistance values of the resistors R1 and R2 of the bias circuit 23 in the electronic tag 100 is to enable the modulation signal when the enable terminal of the bias circuit 23 is connected to a low level. The level value of the center point is deviated from the threshold of the signal input port 24-1 of the microprocessor 24 by about 1/3 (both up and down shifts are possible).

Claims

Rights request

I An electronic label having a casing (1), a circuit device (2), and a display screen (3), the circuit device (2) is disposed in the casing (1), and the display screen (3) is disposed on the casing (1) and It is located at the display window of the casing (1); the circuit device (2) has an antenna device (21), a microprocessor (24), a main crystal circuit (25) and a DC power supply terminal; the microprocessor (24) is provided with a power supply terminal The main crystal terminal (24-13), the display output terminal (24-15) and the signal input port (24-1); the power supply terminal of the microprocessor (24) and the DC power supply terminal of the circuit device (2) are in line; The main crystal terminal (24-13) of the microprocessor (24) is connected to the main crystal circuit (25); the display output terminal (24-15) of the microprocessor (24) is connected to the display screen (3) or through the driving circuit It is connected to the display screen (3); It is characterized in that: the output end of the antenna device (21) is connected to the signal input port (24-1) of the microprocessor (24); the microprocessor (24) is processed by a software program Microprocessor with digitally modulated low-frequency radio wave signal function, which can process low-frequency signals from 4kHz to 2 00kHz.

2. The electronic label according to claim 1, characterized in that: the signal input port (24-1) of the microprocessor (24) is a port having a signal amplification function.

3. The electronic label according to claim 1, characterized in that: the circuit device (2) further comprises a pre-amplification circuit (22); the pre-amplification circuit (22) is provided at the output end of the antenna device (21) and the microprocessor (24) between the signal input ports (24-1).

4. The electronic label according to claim 3, characterized in that: the microprocessor (24) of the circuit device (2) is further provided with a sampling signal output port (24-2); a sample signal output port (24-2) ) Connect to the enable terminal of the preamplifier circuit (22).

5. The electronic tag according to claim 1, characterized in that: the circuit device (3) further comprises a bias circuit (23), the bias circuit (23) is provided at an output end of the antenna device (21) and a microprocessor (24) between the signal input ports (24-1).

6. The electronic tag according to claim 5, characterized in that: the microprocessor (24) of the circuit device (2) is further provided with a sampling signal output port (24-2); a sampling signal output port (24-2) Connect to the enable terminal of the bias circuit (22).

7. The electronic tag according to claim 1, characterized in that: the circuit device (2) further includes a secondary crystal circuit (26), and the microprocessor (24) further includes a secondary crystal terminal (24-14), and a secondary crystal circuit (26) is connected to the auxiliary crystal terminal (24-14) of the microprocessor (24); the oscillation frequency of the auxiliary crystal circuit (26) is between 20kHz and 100kHz, The oscillation frequency of the main crystal circuit (25) is between 400kHz and 40MHz.

8. The electronic label according to any one of claims 1 to 7, characterized in that: the label further comprises a DC power source (4), and an output terminal of the DC power source (4) is connected to a power terminal of the circuit device (2).

9. The electronic tag according to claim 1, characterized in that the process of processing the digitally modulated low-frequency radio wave signal by a microprocessor (24) of the circuit device (2) through a software program is: ① according to the signal input port

(24-1) to determine the presence or absence of signal input; ② to determine the presence or absence of a signal node (61) by comparing the change in the time parameter of the signal waveform; ③ to measure the difference between adjacent signal nodes (61) The symbol length (62) is stored in the data memory (24-9). The collection of this series of symbol lengths (62) forms a data column representing the baseband signal, thereby realizing the software demodulation function; The signal is decoded into an actual data frame, which completes the software decoding process. ⑤ Analyze and process the received data, then control the working state of the microprocessor (24), and display the relevant information through the display screen (3).

10. An electronic shelf label system having a main controller (5) and a plurality of electronic tags (100); the main controller (5) having a computer (51), an exciter (52) and a loop antenna (53); excitation The driver (52) is connected to the computer (51) through its communication interface (52-1); the exciter (52) is connected to the loop antenna (53) by its driver (52-4) and resonance capacitor (52-5); The device (52) has the function of encoding and modulating the information transmitted from the computer (51) to drive the loop antenna (53) and send it to the space; the electronic tag (100) is placed in the range surrounded by the loop antenna (53). Receives the information sent by the main controller (5) and displays specific information; the electronic label (100) has a housing (1), a circuit device (2) and a display screen (3), and the circuit device (2) is set In the casing (1), the display screen (3) is arranged on the casing (1) and located at a display window of the casing (1); the circuit device (2) has an antenna device (21), a microprocessor (24), and a main unit Crystal oscillator circuit (25) and DC power supply terminal; microprocessor (24) with power supply terminal and main crystal The vibration terminal (24-13), the display output terminal (24-15) and the signal input port (24-1); the power supply terminal of the microprocessor (24) and the DC power supply terminal of the circuit device (2) are co-linear; microprocessing The main crystal terminal (24-13) of the controller (24) is connected to the main crystal circuit (25); the display output terminal (24-15) of the microprocessor (24) is connected to the display screen (3) or through the driving circuit and The display screen (3) is connected; it is characterized in that: the output end of the antenna device (21) is connected to the signal input port (24-1) of the microprocessor (24); the microprocessor (24) has a Digitally modulated microprocessor with low frequency radio wave signal function, the frequency of low frequency signal that it can process is between 4kHz and 200kHz; the process of microprocessor (24) processing low frequency radio wave signal through software program is: ① according to the signal input port (24-1) to determine the presence or absence of signal input; ② to determine the presence or absence of a signal node (61) by comparing changes in the time parameter of the signal waveform; ③ to measure the value of the adjacent signal node (61) The symbol length (62) is stored in the data memory (24-9). The collection of this series of symbol length (62) forms a data column representing the baseband signal, thereby implementing the software demodulation function; ④ The baseband signal is decoded into an actual data frame, and the software decoding process is completed; ⑤ Analyze and process the received data, and then control the working state of the microprocessor (24), and display relevant information through the display screen (3).