CN201345104Y - Control switching system for RFID multi-protocols reader - Google Patents
Control switching system for RFID multi-protocols reader Download PDFInfo
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- CN201345104Y CN201345104Y CNU2008202388914U CN200820238891U CN201345104Y CN 201345104 Y CN201345104 Y CN 201345104Y CN U2008202388914 U CNU2008202388914 U CN U2008202388914U CN 200820238891 U CN200820238891 U CN 200820238891U CN 201345104 Y CN201345104 Y CN 201345104Y
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Abstract
The utility model discloses a control switching system for an RFID multi-protocols reader, which comprises a control system, an emitting passage circuit, a receiving passage circuit and a host computer serial port communication circuit. The emitting passage circuit and the receiving passage circuit are connected with the control system, the control system is connected with the host computer serial port communication circuit, the receiving passage circuit comprises an input matching circuit, a controllable band-pass filter, a signal amplification circuit and a controllable demodulation circuit, the input matching circuit is connected with the controllable band-pass filter, the controllable band-pass filter is connected with the signal amplification circuit, the signal amplification circuit is connected with a controllable demodulator, the controllable demodulator and the controllable band-pass filter are directly connected with the control system, emitting signals generated by the emitting passage circuit and the demodulation form of the emitting signals are controlled by the control system, wherein an input end of a modulator is connected with the control system, an output end of the modulator is connected with a power amplification circuit, and the power amplification circuit is connected with an output matching circuit, thereby being capable of realizing switching.
Description
Technical field
The utility model belongs to the radio RF recognition technology field, particularly relates to a kind of soft switch control switched system of RFID multi-protocols read write line.
Background technology
Radio RF recognition technology RFID is a kind of non-contact automatic identification technology, its ultimate principle is to utilize radiofrequency signal and space coupling, be the automatic recognition objective object of transport property of inductive coupling or electromagnetic coupled and obtain related data, make item tracking and information sharing to carry out in wider and even global range by background network.As a kind of emerging automatic identification technology, radio RF recognition technology RFID has obtained developing rapidly in recent years, and domestic application based on RFID comprises urban transportation card system and second generation I.D. etc., and has formed a vigorous new industry gradually.But then, along with the RFID technology rapid development, the various communication protocols of numerous and confused in the world release adapt to different application scenarios, and are incompatible between the agreement, and the standard disunity has become one of key factor of restriction RFID development.
The utility model content
The purpose of this utility model provides a kind of simple in structure, reliable operation, can finish the control switched system of the RFID multi-protocols read write line that freely switches between the different agreement automatically.
For achieving the above object, the utility model is by the following technical solutions:
The utility model comprises control system, transmission channel circuit, receiving cable circuit and host computer serial communication circuit; The transmission channel circuit all is connected with control system with the receiving cable circuit, control system is connected with the host computer serial communication circuit, above-mentioned receiving cable circuit comprises input matching circuit, controlled bandpass filter, signal amplification circuit and controlled demodulator circuit, wherein, the input matching circuit controlled bandpass filter that links to each other, controlled bandpass filter connects signal amplification circuit, signal amplification circuit connects controlled detuner, and controlled detuner also directly is connected with control system with controlled bandpass filter; The control of the controlled system of modulation system that transmits and transmit that above-mentioned transmission channel circuit is produced, wherein the input end of modulator is connected with control system, the output terminal of modulator connects power amplification circuit, and power amplification circuit connects output matching circuit.
Above-mentioned controlled demodulator circuit comprises first diode, equivalent resistance and the 4th electric capacity, and equivalent resistance is connected in parallel with the 4th electric capacity and then is connected with the negative electrode of first diode; Above-mentioned equivalent resistance comprises first resistance and the 5th resistance that is connected in series, and wherein, the common port of first resistance and the 5th resistance is connected in the control system.
Above-mentioned controlled bandpass filter is a single order parallel resonance bandpass filter, and it comprises the 6th electric capacity and the 3rd resistance that is connected in parallel, and wherein the common port of the 6th electric capacity and the 3rd resistance is connected in the control system.
Above-mentioned RFID multi-protocols read write line is two agreement rfid interrogators of ISO15693 and 14443A, B standard.
Adopt the utility model of technique scheme, the running parameter of hardware circuit is automaticallyed switch by the on-off circuit by software control, be referred to as soft switch and switch.Like this, switch conversion or the conversion that realizes circuit working state, make circuit carry out automatic reception and processing at multiple signal by soft switch.But running parameter by the software control automatic switch-over circuit, make read write line can finish read-write operation to different agreement RFID radio-frequency card, satisfied the demand that radio-frequency card changes running parameter, reduce the cost that the different agreement radio-frequency card is used, helped popularizing of radio-frequency card on a large scale.In addition, the consideration of flexible design and system cost by circuit, use soft switch handoff technique and can constitute two agreements, RFID rf read-write device as ISO15693,14443A, B standard, and form the above multi-protocols read write line of two agreements by expansion on this basis, also comprise simultaneously being applied on other equipment or circuit that needs the RFID technology.Adopt soft switch switching circuit to realize that multiprotocol label can satisfy multiple applications needs, help RFID technical development and popularization.
Description of drawings
Fig. 1 is that figure is switched in soft switch control of the present utility model;
Fig. 2 is a theory diagram of the present utility model;
Fig. 3 is the controlled demodulator circuit figure of embodiment 1 in the utility model;
Fig. 4 is the circuit diagram of the controlled bandpass filter of embodiment 1 in the utility model.
Embodiment
As shown in Figure 1, in the utility model RFID multi-protocols read write line according to host computer order determine the standard of received signal, by adjusting running parameter and duty by the controlable electric current of software control, like this, the running parameter of hardware circuit just can be controlled by the software of host computer, in the utility model it is referred to as soft switch and switches.Switch conversion or the conversion that realizes the hardware circuit duty by above-mentioned soft switch, receiving cable circuit and transmission channel circuit can be handled according to the multiple input signal of different agreement.Above-mentioned controlable electric current mainly comprises controlled bandpass filter and controlled detuner.In the present embodiment, RFID multi-protocols read write line is two agreement rfid interrogators of ISO15693 and 14443A, B standard.
Its main handoff procedure as shown in Figure 1, the control system in the multi-protocols read write line of RFID at first starts the receiving cable circuit, determines the standard of received signal then according to the order of host computer.If 14443A, B standard, then the microprocessor in the control system is exported 0 pattern to controlled demodulator circuit by steering logic from I/O mouth RB2, change its circuit parameter and realize the detection processing of 14443A, B signal, I/O mouth RB3 in its control system is output as high-impedance state in addition, and then adjusts the centre frequency of controlled bandpass filter; If 15693 standards, then the I/O mouth RB2 in the control system is output as high-impedance state to controlled demodulator circuit, and the I/O mouth RB3 in its control system is output as 0 pattern in addition, adjusts the centre frequency of controlled bandpass filter.Behind the running parameter that has changed its hardware circuit, its receiving cable circuit just can receive handles signal between the different communication protocol, and the also control of controlled system of the modulation system that transmits and transmit in the transmission channel circuit.
For implementing the method in the utility model, adopted following hardware circuit design:
As shown in Figure 2, the soft switch control switched system of RFID multi-protocols read write line comprises control system, transmission channel circuit, receiving cable circuit and host computer serial communication circuit.Transmission channel circuit and receiving cable circuit all communicate by antenna and rfid card, in addition, the transmission channel circuit all is connected with control system with the receiving cable circuit, control system is connected with the host computer serial communication circuit, the host computer serial communication circuit connects the host computer of peripheral hardware, above-mentioned host computer can be a PC, above-mentioned control system is core design with the high-speed microprocessor, above-mentioned host computer serial communication circuit comprises RS232 interface circuit and usb circuit, is technology well known to those of ordinary skill in the art.Like this, the order of host computer can be sent to control system by the host computer serial communication circuit, and control system acts accordingly according to order again.In addition, for making the utility model can operate as normal, also should comprise peripheral circuits such as power circuit in the utility model, above-mentioned power circuit all is connected with control system, transmission channel circuit, receiving cable circuit and host computer serial communication circuit, and power circuit is a technology well known to those of ordinary skill in the art.
In the utility model, the receiving cable circuit comprises input matching circuit, controlled bandpass filter, signal amplification circuit and controlled demodulator circuit.The above-mentioned input matching circuit controlled bandpass filter that links to each other, controlled bandpass filter connects signal amplification circuit, and signal amplification circuit connects controlled detuner, and controlled detuner also directly is connected with control system with controlled bandpass filter.Like this, in the utility model, controlled bandpass filter and controlled detuner are based on the multiparameter controlable electric current of soft switch switched design, control signal comes from control system, under the control signal effect, controlable electric current can work in different signal frequencies, thereby carries out the processing of different agreement input signal.
In the utility model, the control of the controlled system of modulation system that transmits and transmit that the transmission channel circuit is produced, wherein the input end of modulator is connected with control system, and the output terminal of modulator connects power amplification circuit, and power amplification circuit connects output matching circuit.In the present embodiment, RFID multi-protocols read write line is two agreement rfid interrogators of the ISO15693 of 13.56MHz and 14443A, B standard.
Specifically, the principle of work of RFID multi-protocols read write line is: 13.56MHz crystal oscillator signal is the clock signal of microprocessor, use as the emission carrier signal again simultaneously, whole read write line is the core design of control system with the high-speed microprocessor, and above-mentioned high-speed microprocessor can be PIC18F252.After the RFID multi-protocols read write line energized, under the control of system program, RFID multi-protocols read write line is outwards launched the modulated radio signal of 13.56MHz by antenna, and forms the detection zone of certain limit; When radio-frequency (RF) tag enters detection zone, by inductive coupling radio-frequency (RF) energy is converted to induced voltage, and becomes direct current by bridge rectifier, after filtering, voltage stabilizing, become the operating voltage of radio-frequency (RF) tag again; Radio-frequency card demodulates order and data and delivers to steering logic according to communication protocol from radio-frequency pulse afterwards, steering logic receives instruction and finishes storage, sends data or other operation, radio-frequency (RF) tag sends data if desired, it will carry out the subcarrier load-modulate with digital coding with a kind of subcarrier or two kinds of subcarriers according to the communication protocol agreement, give read write line by antenna transmission then.In general, work in the RFID international standard of 13.56MHZ, the ISO14443A standard adopts Manchester Manchester coding, and its subcarrier frequency is 847KHZ; The ISO14443B standard adopts nrz encoding, and its subcarrier frequency equally also is 847KHZ; The ISO15693 standard adopts Manchester Manchester coding, and its subcarrier frequency is 423.75kHz or 484.28kHz.Above-mentioned coding techniques is technology well known to those of ordinary skill in the art.After the read write line received signal, switch the change circuit parameter, the label signal of receiving is carried out detection and Filtering Processing, send into microprocessor after the demodulation and carry out processing such as completeness check, obtain label information at last and finish the rfid card read operation by soft switch.
For freely switching controlable electric current, the controlled demodulator circuit in the utility model and the principle of work of controlled bandpass filter are as follows:
As shown in Figure 3, the controlled demodulator circuit in the utility model comprises the first diode D1, equivalent resistance and the 4th capacitor C 4, and equivalent resistance is connected in parallel with the 4th capacitor C 4 and then is connected with the negative electrode of the first diode D1.Above-mentioned equivalent resistance comprises first resistance R 1 and the 5th resistance R 5 that is connected in series, and wherein, the common port of first resistance R 1 and the 5th resistance R 5 is connected in the control system.
The controlled demodulator circuit principle of work of switching based on the soft switch of the utility model is as follows:
For guaranteeing the compatibility of circuit to the different agreement label signal, detecting circuit should possess changeable property.For 15693 standards, label adopts the load-modulate mode of band subcarrier to the communication of read write line.Read write line determines that with first of protocol header selecting a kind of subcarrier still is two kinds of subcarriers, when using a kind of subcarrier, and frequency f
s=423.75KHz; When using two kinds of subcarriers, frequency f
S1=423.75KHz, frequency f
S2=484.28KHz; For 14443 standards, subcarrier frequency is all 847.5KHz.Therefore detecting circuit will possess the ability of better detection 423.75KHz, 484.28KHz, 847.5KHz signal simultaneously.
Circuit is made up of diode, electric capacity and resistance, and input signal is the amplitude modulated carrier wave on the antenna.Diode D1 conducting when the positive half cycle of signal arrives, electric current charges to capacitor C, and charging rate is R
DC, wherein R
DBe the conducting resistance of D1, along with the charging of C, output voltage rises; Diode D1 ends when the negative half period of signal arrives, and capacitor C is to conductive discharge, and discharge time constant is RC, by dried RC＞＞R
DC, so diode D1 conducting again when the electric charge on the capacitor C has not been put, C recharges, the appearance that so goes round and begins again, output voltage just changes with the envelope of modulated wave.
The quality that detection is handled in the circuit depends on the RC time constant, capacitor C is selected 68PF, and resistance R is formed an equivalent controllable resistor by R1, R5, for the subcarrier 423.75KHz and the 484.28KHz of 15693 standards, its relative carrier wave 13.56MHz is little a lot, and time constant RC will be more greatly; And the subcarrier 847.5KHz of 14443 standards is higher relatively, and RC is smaller.So for 15693 standards, putting single-chip processor i/o mouth RB2 is high-impedance state, be equivalent to disconnect equivalent resistance R=R1+R5; For 14443 standards, put RB2 for output 0 pattern, be equivalent to ground connection, so R=R1.F under two kinds of situations
c=1/ (RC)=0.147MHz or 0.181MHz, carrier frequency fs=13.56MHz all satisfies fc＜fs, and circuit can carry out normal detection to be handled.
As shown in Figure 4, controlled bandpass filter is a single order parallel resonance bandpass filter, and it comprises that the 6th capacitor C 6 that is connected in parallel and the common port of the 3rd resistance R 3, the six capacitor C 6 and the 3rd resistance R 3 are connected in the control system.
The controlled filtering circuit principle of work of switching based on the soft switch of the utility model is as follows:
Filtering circuit adopts single order parallel resonance bandpass filtering, is the signal of compatible different frequency simultaneously, and its centre frequency and bandwidth should possess controlled characteristics.The centre frequency of control bandpass filter and the method that bandwidth adopts external shunt capacitance, resistance, as shown in Figure 3, the other end of shunt capacitance C6, resistance R 3 meets the I/O mouth RB3 of single-chip microcomputer.Put RB3 and be output high resistant pattern, be equivalent to disconnect, shunt capacitance, resistance are invalid to resonant circuit; Put RB3 for output 0 pattern, be equivalent to ground connection, shunt capacitance, resistance are to effectively parallel connection of resonant circuit.
For 14443 standards, put RB3 and be input high resistant pattern, C6, R3 disconnect.Its subcarrier signal frequency is 847.5KHz, and baseband signal f frequency is 106KHz, so the bandpass filter centre frequency:
fo＝847.5KHz
Three dB bandwidth
B≥2f＝212KHz
So the Q value of its parallel resonance is
fo/B≤4
Power taking sense L1 value is 100 μ H, capacitor C 5 value 360pF, resonance quite rate about 847.5kHz; Can calculate its parallel resistance thus
R2≤QωL≤2K
Value 1.2k is comparatively suitable in the actual debugging.
For 15693 standards, put RB3 and be output 0 pattern, C6, R3 are effectively in parallel to resonant circuit.It has two subcarrier signals of 423.75KHz and 484.28KHz, and the simplified design centre frequency is:
fo＝(f
1+f
2)/2＝452KHz
Baseband signal f frequency is 26.5KHz, so lower limiting frequency:
f
1-f＝423.75KHz-26.5KHz＝397KHz
Upper cut off frequency:
f
2+f＝484.28KHz+26.5KHz＝511KHz
Three dB bandwidth:
B≥511-397＝114KHz
The Q value is:
fo/B≤4
Its parallel resistance:
R≤QωL≤1.13K
L1 is constant in the power taking sense, capacitor C 6 value 1000pF, resonance quite rate about 452kHz; Getting R3 in the debugging is 3.3k, then the equivalent resistance of parallel resonance:
R＝R2//R3＝0.88k＜1.13k
Meet the demands.
Present embodiment as different from Example 1, in the present embodiment, RFID multi-protocols read write line is two agreement rfid interrogators of the ISO18000-3 of 13.56MHz and 14443A, B standard.Wherein, ISO18000-3 has two patterns: pattern 1 and ISO15693 protocol-compliant, so its controlable electric current can adopt and the corresponding to soft switch switching circuit of the controlable electric current of ISO15693 agreement; And pattern 2 is encoded for adopting MFM, and the centre frequency of its subcarrier is 969～3013kHz.Based on this point, in the controlable electric current of corresponding ISO18000-3 pattern 2, the time constant RC in the detecting circuit is also smaller slightly, and it is corresponding big that the bandwidth range of bandpass filtering is wanted.
The other technologies feature is identical with embodiment 1.
The controlable electric current that switches based on the soft switch of the utility model also can be applicable in other circuit that needs transformation parameter except that being applied to controlled filtering and detecting circuit; And by the expansion on the circuit design, the conversion of circuit parameter can be applicable in other different communication protocols.
Claims (4)
1, a kind of control switched system of RFID multi-protocols read write line, it comprises control system, transmission channel circuit, receiving cable circuit and host computer serial communication circuit; Described transmission channel circuit all is connected with control system with the receiving cable circuit, control system is connected with the host computer serial communication circuit, it is characterized in that: described receiving cable circuit comprises input matching circuit, controlled bandpass filter, signal amplification circuit and controlled demodulator circuit, described input matching circuit connects controlled bandpass filter, controlled bandpass filter connects signal amplification circuit, signal amplification circuit connects controlled detuner, and described controlled detuner also directly is connected with control system with controlled bandpass filter; The control of the controlled system of modulation system that transmits and transmit that described transmission channel circuit is produced, wherein the input end of modulator is connected with control system, the output terminal of modulator connects power amplification circuit, and power amplification circuit connects output matching circuit.
2, the control switched system of RFID multi-protocols read write line according to claim 1, it is characterized in that: described controlled demodulator circuit comprises first diode (D1), equivalent resistance and the 4th electric capacity (C4), and described equivalent resistance is connected in parallel with the 4th electric capacity (C4) and then is connected with the negative electrode of first diode (D1); Described equivalent resistance comprises first resistance (R1) and the 5th resistance (R5) that is connected in series, and wherein, the common port of first resistance (R1) and the 5th resistance (R5) is connected in the control system.
3, the control switched system of RFID multi-protocols read write line according to claim 1, it is characterized in that: described controlled bandpass filter is a single order parallel resonance bandpass filter, it comprises the 6th electric capacity (C6) and the 3rd resistance (R3) that is connected in parallel, and the common port of described the 6th electric capacity (C6) and the 3rd resistance (R3) is connected in the control system.
4, the control switched system of RFID multi-protocols read write line according to claim 1 is characterized in that: described RFID multi-protocols read write line is two agreement rfid interrogators of ISO15693 and 14443A, B standard.
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| Application Number | Priority Date | Filing Date | Title |
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| CNU2008202388914U CN201345104Y (en) | 2008-12-29 | 2008-12-29 | Control switching system for RFID multi-protocols reader |
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| CNU2008202388914U CN201345104Y (en) | 2008-12-29 | 2008-12-29 | Control switching system for RFID multi-protocols reader |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101770561B (en) * | 2008-12-29 | 2012-05-16 | 郑州大学 | Switching method and control switching system thereof of radio frequency identification device (RFID) multi-protocol reader-writer |
| CN102496055A (en) * | 2011-12-22 | 2012-06-13 | 广州中大微电子有限公司 | RFID demodulation mode automatic identification method and automatic identification circuit thereof |
-
2008
- 2008-12-29 CN CNU2008202388914U patent/CN201345104Y/en not_active Expired - Fee Related
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101770561B (en) * | 2008-12-29 | 2012-05-16 | 郑州大学 | Switching method and control switching system thereof of radio frequency identification device (RFID) multi-protocol reader-writer |
| CN102496055A (en) * | 2011-12-22 | 2012-06-13 | 广州中大微电子有限公司 | RFID demodulation mode automatic identification method and automatic identification circuit thereof |
| CN102496055B (en) * | 2011-12-22 | 2015-02-18 | 广州中大微电子有限公司 | RFID demodulation mode automatic identification method and automatic identification circuit thereof |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| EE01 | Entry into force of recordation of patent licensing contract |
Assignee: Henan Information Consultation Design & Research Co., Ltd. Assignor: Zhengzhou University Contract record no.: 2010410000104 Denomination of utility model: Control switching system for RFID multi-protocols reader Granted publication date: 20091111 License type: Exclusive License Record date: 20100913 |
|
| C17 | Cessation of patent right | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20091111 Termination date: 20101229 |