CN104899534A - Non-contact type card reader - Google Patents
Non-contact type card reader Download PDFInfo
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- CN104899534A CN104899534A CN201510280314.6A CN201510280314A CN104899534A CN 104899534 A CN104899534 A CN 104899534A CN 201510280314 A CN201510280314 A CN 201510280314A CN 104899534 A CN104899534 A CN 104899534A
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- media reader
- contact media
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Abstract
The present invention relates to a non-contact type card reader. A series-connected LC parallel resonance circuit is additionally arranged between a receiving circuit and an antenna coil of a conventional non-contact type card reader; moreover, a preset threshold value is set to be as small as possible, which shows that a resonant frequency of the LC parallel resonance circuit is as close as possible to a carrier frequency of a chip of the non-contact type card reader; the closer the resonant frequency of the LC parallel resonance circuit is to the carrier frequency of a chip of the non-contact type card reader, the larger the generated inhibiting effect on a carrier signal can be, so that a signal intensity ratio of a card signal to the carrier signal is increased, i.e.,, the card signal is amplified under the condition that the carrier signal is unchanged, and under the condition of not changing a Q value of the antenna coil and an internal receiving gain of the chip of the non-contact type card reader, antenna receiving sensitivity of the non-contact card reader is improved.
Description
Technical field
The present invention relates to a kind of Non-contact Media Reader.
Background technology
Current Non-contact Media Reader adopts 13.56MHz frequency standard, for the technical field of near-field communication, be according to ISO14443 international standard, and the payment standards of the EMV Contactless Specifications for payment systems of EMVco formulation design.Current non-contact card mainly replys data by load-modulate technology to card reader, and card data signal amplitude is very little.Therefore, the antenna of Non-contact Media Reader needs enough receiving sensitivities to realize best reception.
The receiving sensitivity of non-contact card reader antenna is mainly promoted at present by chip internal receiving gain two kinds of modes of the Q value or raising Non-contact Media Reader that improve receiving antenna.But improve the Q value of receiving antenna, mean that non-contact card reader antenna is easy to be affected by the close of card, easily produce blind area, consistance is also relatively poor.Improve the chip internal receiving gain of Non-contact Media Reader, noise, while enlarging card signal, also can amplify by chip receiving circuit, causes chip to be decoded and makes mistakes, Card Reader failure.
Disclosed in application number 200820158571.8, Non-contact radio frequency card reader comprises microcontroller, noncontact device card reader chip FM1702SL, amplifying circuit, one-level resonant circuit, secondary resonant circuit, shaping circuit, MCU controls noncontact device card reader chip FM1702SL by SPI communication interface, the continuous outgoing carrier signal of this chip the 6th pin TX2, by amplifying circuit amplify after sequentially coupling to for filtering higher hamonic wave and by signal resonance amplification one-level LC resonant circuit and secondary LC resonant circuit, carrier signal is amplified and makes antenna has enough energy launch radio magnetic wave to the outside.
But when receiving radio magnetic wave, because carrier signal amplification can suppress the card signal that receives, thus significantly reduce the sensitivity of card reader receiving antenna.
Summary of the invention
Technical matters to be solved by this invention is: provide a kind of Non-contact Media Reader, improves card reader antenna receiving sensitivity.
In order to solve the problems of the technologies described above, the technical solution used in the present invention is:
A kind of Non-contact Media Reader, comprise Non-contact Media Reader chip, EMC wave filter, impedance matching circuit, aerial coil and receiving circuit, described Non-contact Media Reader chip is connected with EMC wave filter and receiving circuit respectively; Described EMC wave filter is connected with aerial coil by impedance matching circuit; Also comprise LC antiresonant circuit; Described aerial coil is connected with receiving circuit by series LC antiresonant circuit; The difference of the resonance frequency of described LC antiresonant circuit and the carrier frequency of Non-contact Media Reader chip is less than pre-set threshold value.
Beneficial effect of the present invention is: the LC antiresonant circuit increasing series connection between the receiving circuit and aerial coil of traditional Non-contact Media Reader, and it is little as far as possible to arrange pre-set threshold value, illustrate that the resonance frequency of LC antiresonant circuit is as far as possible close to the carrier frequency of Non-contact Media Reader chip, when the resonance frequency of LC antiresonant circuit and Non-contact Media Reader chip carrier frequency more close to time, larger inhibiting effect can be produced to carrier signal, and then improve the signal intensity ratio of card signal and carrier signal, be equivalent to when carrier signal is constant, card signal is amplified, thus improve non-contact card reader antenna receiving sensitivity.
Accompanying drawing explanation
Fig. 1 is the structural representation of a kind of Non-contact Media Reader of the specific embodiment of the invention;
Label declaration:
10, Non-contact Media Reader chip; 20, EMC wave filter; 30, impedance matching circuit; 40, aerial coil; 50, LC antiresonant circuit; 60, receiving circuit.
Embodiment
By describing technology contents of the present invention in detail, realized object and effect, accompanying drawing is coordinated to be explained below in conjunction with embodiment.
The design of most critical of the present invention is: the LC antiresonant circuit increasing series connection between the receiving circuit and aerial coil of traditional Non-contact Media Reader, and the difference of the resonance frequency of described LC antiresonant circuit and the carrier frequency of Non-contact Media Reader chip is less than pre-set threshold value, arranges pre-set threshold value little as far as possible.
The explanation of technical terms that the present invention relates to:
Please refer to Fig. 1, a kind of Non-contact Media Reader provided by the invention, comprise Non-contact Media Reader chip 10, EMC wave filter 20, impedance matching circuit 30, aerial coil 40 and receiving circuit 60, described Non-contact Media Reader chip 10 is connected with EMC wave filter 20 and receiving circuit 60 respectively; Described EMC wave filter 20 is connected with aerial coil 40 by impedance matching circuit 30; Also comprise LC antiresonant circuit 50; Described aerial coil 40 is connected with receiving circuit 60 by series LC antiresonant circuit 50; The difference of the resonance frequency of described LC antiresonant circuit and the carrier frequency of Non-contact Media Reader chip is less than pre-set threshold value.
From foregoing description, beneficial effect of the present invention is: the LC antiresonant circuit increasing series connection between the receiving circuit and aerial coil of traditional Non-contact Media Reader, and it is little as far as possible to arrange pre-set threshold value, illustrate that the resonance frequency of LC antiresonant circuit is as far as possible close to the carrier frequency of Non-contact Media Reader chip, when the resonance frequency of LC antiresonant circuit and Non-contact Media Reader chip carrier frequency more close to time, larger inhibiting effect can be produced to carrier signal, and then improve the signal intensity ratio of card signal and carrier signal, be equivalent to when carrier signal is constant, card signal is amplified, thus improve non-contact card reader antenna receiving sensitivity.
Further, described pre-set threshold value is 847KHz.
The antenna receiving sensitivity of usual existing Non-contact Media Reader is about 3.5mV (3.5mV is authentication requesting).If but antenna environment is bad, or antenna size is less, receiving sensitivity can be deteriorated, and according to circumstances, likely sensitivity can be about 10mV (value is less, represents that sensitivity is higher).In this case, if add LC resonant circuit, then receiving sensitivity can improve a lot, and is easy to reach 3.5mV, or even 1mV.
In theory, LC resonant frequency range is between 13.56MHz-847KHz to 13.56MHz+847KHz, and optimal value is 13.56MHz.Sensitivity during optimal value can reach 1mV, even less.(because of testing apparatus problem, below 1mV cannot test.)
| Pre-set threshold value | Antenna receiving sensitivity | Pre-set threshold value | Antenna receiving sensitivity |
| 0.05MHz | 1.0mV | 0.45MHz | 3.0mV |
| 0.10MHz | 1.0mV | 0.50MHz | 3.1mV |
| 0.15MHz | 2.0mV | 0.55MHz | 3.1mV |
| 0.20MHz | 2.3mV | 0.60MHz | 3.3mV |
| 0.25MHz | 2.4mV | 0.65MHz | 3.3mV |
| 0.30MHz | 2.6mV | 0.70MHz | 3.3mV |
| 0.35MHz | 2.8mV | 0.75MHz | 3.5mV |
| 0.40MHz | 3.0mV | 0.80MHz | 3.5mV |
As seen from the above table, when usual antenna receiving sensitivity is 3.5mV, corresponding pre-set threshold value is 0.80MHz, and in actual experiment process, the pre-set threshold value of employing is 0.847MHz.
Further, the carrier frequency of described Non-contact Media Reader chip is 13.56MHz, and the resonant frequency range of described LC antiresonant circuit is between 13.56MHz-847KHz to 13.56MHz+847KHz.
Further, the subcarrier frequency of described Non-contact Media Reader chip is 847KHz; The card data rate of described Non-contact Media Reader chip is 106KHz.
Further, the optimal value of the resonance frequency of described LC antiresonant circuit is 13.56MHz.
In actual experiment process, the optimal value of the resonance frequency of LC antiresonant circuit is 13.56MHz, and now, antenna receiving sensitivity can reach 1mV.
Further, described Non-contact Media Reader chip comprises modulation module and demodulation module;
Described modulation module is connected with EMC wave filter; Described modulation module, transmits to EMC wave filter for modulating and sending;
Described demodulation module is connected with receiving circuit; Described demodulation module, for receiving the Received signal strength that also demodulation receiving circuit sends.
Further, described in transmit as differential square signals, chip output power can be made to reach maximum.
Further, described receiving circuit comprises division module, for obtaining carrier signal and card signal.
The embodiment of the present invention 1
The principle of work of traditional Non-contact Media Reader:
Traditional Non-contact Media Reader comprises Non-contact Media Reader chip, EMC wave filter, impedance matching circuit, aerial coil also have receiving circuit.Non-contact Media Reader chip is used for transmitting and Received signal strength, the modulation and demodulation of settling signal.
When Non-contact Media Reader transmits, radio-frequency driven pin TX1, TX2 pin of Non-contact Media Reader chip exports the differential square signals of 13.56MHz, is transferred to aerial coil again radiate after EMC wave filter filtering higher hamonic wave through impedance matching circuit.
During Non-contact Media Reader Received signal strength, receiving circuit obtains carrier signal and card signal from dividing potential drop aerial coil, and receiving circuit is exported to after Non-contact Media Reader chip carries out inter-process, demodulation by RX pin and obtained card data.
Non-contact Media Reader provided by the invention is a LC antiresonant circuit of connecting between receiving circuit with aerial coil on traditional Non-contact Media Reader basis, and its resonance frequency is about 13.56MHz.
The principle of work of Non-contact Media Reader provided by the invention is:
When LC antiresonant circuit is when being the signal of 13.56MHz by frequency, its impedance is maximum; When being slowly the signal of 13.56MHz away from frequency, its impedance slowly diminishes.
Arrange described Non-contact Media Reader chip operation in the carrier frequency of 13.56MHz, subcarrier frequency is 847KHz, and therefore, the actual effective frequency of card signal is 13.56MHz-847KHz and 13.56MHz+847KHz.
After increasing LC antiresonant circuit, LC antiresonant circuit suppresses larger to the carrier signal that frequency is 13.56MHz, card signal is suppressed relatively little, be equivalent to add signal intensity ratio between card signal and carrier signal (such as: adopt traditional Non-contact Media Reader, the amplitude of card signal and carrier signal is 1:1, after adopting Non-contact Media Reader provided by the invention, the amplitude of card signal and carrier signal is 3:1).When chip reception pin there being the carrier signal of same frequency, the amplitude of card signal becomes large.Therefore, LC antiresonant circuit is equivalent to an amplifier in Non-contact Media Reader provided by the invention, and its enlargement factor is according to relevant to the Q value of LC antiresonant circuit.
Send in data at Non-contact Media Reader: the resonance frequency arranging LC antiresonant circuit is about 13.56MHz.When 13.56MHz, the impedance of LC antiresonant circuit is maximum, and be real impedance, the Q value of card reader antenna coil, coupling and resonance frequency are not affected substantially, therefore LC antiresonant circuit on Non-contact Media Reader transmitted power, send data waveform and also substantially do not affect.
Receive in data at Non-contact Media Reader: during receiving card data, card signal is through LC antiresonant circuit, card signal is entered Non-contact Media Reader chip by after LC antiresonant circuit " amplification ", Non-contact Media Reader chip carries out demodulation process to the card signal received, and obtains card data.
In the whole course of work, do not need the Q value changing aerial coil, do not need to change Non-contact Media Reader chip internal receiving gain yet, only rely on LC antiresonant circuit just can substantially increase card reader receiving sensitivity.
In sum, a kind of Non-contact Media Reader provided by the invention, the LC antiresonant circuit of series connection is increased between the receiving circuit and aerial coil of traditional Non-contact Media Reader, and it is little as far as possible to arrange pre-set threshold value, illustrate that the resonance frequency of LC antiresonant circuit is as far as possible close to the carrier frequency of Non-contact Media Reader chip, when the resonance frequency of LC antiresonant circuit and Non-contact Media Reader chip carrier frequency more close to time, larger inhibiting effect can be produced to carrier signal, and then improve the signal intensity ratio of card signal and carrier signal, be equivalent to when carrier signal is constant, card signal is amplified, when not changing Q value and the Non-contact Media Reader chip internal receiving gain of aerial coil, improve non-contact card reader antenna receiving sensitivity.
The foregoing is only embodiments of the invention; not thereby the scope of the claims of the present invention is limited; every equivalents utilizing instructions of the present invention and accompanying drawing content to do, or be directly or indirectly used in relevant technical field, be all in like manner included in scope of patent protection of the present invention.
Claims (8)
1. a Non-contact Media Reader, comprises Non-contact Media Reader chip, EMC wave filter, impedance matching circuit, aerial coil and receiving circuit, and described Non-contact Media Reader chip is connected with EMC wave filter and receiving circuit respectively; Described EMC wave filter is connected with aerial coil by impedance matching circuit; It is characterized in that, also comprise LC antiresonant circuit; Described aerial coil is connected with receiving circuit by series LC antiresonant circuit; The difference of the resonance frequency of described LC antiresonant circuit and the carrier frequency of Non-contact Media Reader chip is less than pre-set threshold value.
2. a kind of Non-contact Media Reader according to claim 1, is characterized in that, described pre-set threshold value is 847KHz.
3. a kind of Non-contact Media Reader according to claim 1, it is characterized in that, the carrier frequency of described Non-contact Media Reader chip is 13.56MHz, and the resonant frequency range of described LC antiresonant circuit is between 13.56MHz-847KHz to 13.56MHz+847KHz.
4. a kind of Non-contact Media Reader according to claim 3, is characterized in that, the subcarrier frequency of described Non-contact Media Reader chip is 847KHz.
5. a kind of Non-contact Media Reader according to claim 3, is characterized in that, the optimal value of the resonance frequency of described LC antiresonant circuit is 13.56MHz.
6. a kind of Non-contact Media Reader according to claim 1, is characterized in that, described Non-contact Media Reader chip comprises modulation module and demodulation module;
Described modulation module is connected with EMC wave filter; Described modulation module, transmits to EMC wave filter for modulating and sending;
Described demodulation module is connected with receiving circuit; Described demodulation module, for receiving the Received signal strength that also demodulation receiving circuit sends.
7. a kind of Non-contact Media Reader according to claim 6, is characterized in that, described in transmit as differential square signals.
8. a kind of Non-contact Media Reader according to claim 1, is characterized in that, described receiving circuit comprises division module, for obtaining carrier signal and card signal.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105225317A (en) * | 2015-10-03 | 2016-01-06 | 上海大学 | A kind of network access control system of multichannel centralized management |
| CN110598498A (en) * | 2019-09-12 | 2019-12-20 | 北京维普无限智能技术有限公司 | Method for improving signal identification capability of non-contact card reader |
Citations (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1146475A1 (en) * | 1994-03-30 | 2001-10-17 | Mitsubishi Denki Kabushiki Kaisha | Noncontact IC card, card reader/writer, and card system |
| DE69929103T2 (en) * | 1998-03-20 | 2006-08-31 | Hid Corp., Irvine | Transponder system and procedure |
| CN1959697A (en) * | 2006-11-17 | 2007-05-09 | 蒋南峰 | Long-range card read head for ID cards in mid frequency and in radio frequency |
| US20070229281A1 (en) * | 2006-03-15 | 2007-10-04 | Semiconductor Energy Laboratory Co., Ltd. | Semiconductor device |
| CN101706879A (en) * | 2009-11-12 | 2010-05-12 | 武汉盛华微系统技术股份有限公司 | Uhf reader demodulation circuit |
| US20110057610A1 (en) * | 2006-09-29 | 2011-03-10 | Semiconductor Energy Laboratory Co., Ltd. | Wireless power storage device, semiconductor device including the wireless power storage device, and method for operating the same |
| CN102570060A (en) * | 2010-12-15 | 2012-07-11 | 上海安费诺永亿通讯电子有限公司 | CMMB (China Mobile Multimedia Broadcasting) antenna system used for communication terminal and matching method thereof |
| JP2013097957A (en) * | 2011-10-31 | 2013-05-20 | Shimadzu Corp | Quadrupole type mass spectroscope |
| CN103166634A (en) * | 2011-12-09 | 2013-06-19 | 国民技术股份有限公司 | Method and device for adjusting resonant frequency of inductance-capacitance parallel resonant cavities |
| CN103190083A (en) * | 2010-10-29 | 2013-07-03 | 索尼公司 | Portable communication device, reader/writer device, and resonant frequency adjustment method |
| CN203149603U (en) * | 2013-01-17 | 2013-08-21 | 公安部第三研究所 | Identification reader-writer for T5557 radio frequency cards |
| CN103699918A (en) * | 2013-12-30 | 2014-04-02 | 威海北洋电气集团股份有限公司 | RFID (radio frequency identification) tag reader-writer |
| CN103856250A (en) * | 2012-12-05 | 2014-06-11 | 三星电子株式会社 | Smart NFC antenna matching network system and user device including the same |
-
2015
- 2015-05-28 CN CN201510280314.6A patent/CN104899534B/en active Active
Patent Citations (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1146475A1 (en) * | 1994-03-30 | 2001-10-17 | Mitsubishi Denki Kabushiki Kaisha | Noncontact IC card, card reader/writer, and card system |
| DE69929103T2 (en) * | 1998-03-20 | 2006-08-31 | Hid Corp., Irvine | Transponder system and procedure |
| US20070229281A1 (en) * | 2006-03-15 | 2007-10-04 | Semiconductor Energy Laboratory Co., Ltd. | Semiconductor device |
| US20110057610A1 (en) * | 2006-09-29 | 2011-03-10 | Semiconductor Energy Laboratory Co., Ltd. | Wireless power storage device, semiconductor device including the wireless power storage device, and method for operating the same |
| CN1959697A (en) * | 2006-11-17 | 2007-05-09 | 蒋南峰 | Long-range card read head for ID cards in mid frequency and in radio frequency |
| CN101706879A (en) * | 2009-11-12 | 2010-05-12 | 武汉盛华微系统技术股份有限公司 | Uhf reader demodulation circuit |
| CN103190083A (en) * | 2010-10-29 | 2013-07-03 | 索尼公司 | Portable communication device, reader/writer device, and resonant frequency adjustment method |
| CN102570060A (en) * | 2010-12-15 | 2012-07-11 | 上海安费诺永亿通讯电子有限公司 | CMMB (China Mobile Multimedia Broadcasting) antenna system used for communication terminal and matching method thereof |
| JP2013097957A (en) * | 2011-10-31 | 2013-05-20 | Shimadzu Corp | Quadrupole type mass spectroscope |
| CN103166634A (en) * | 2011-12-09 | 2013-06-19 | 国民技术股份有限公司 | Method and device for adjusting resonant frequency of inductance-capacitance parallel resonant cavities |
| CN103856250A (en) * | 2012-12-05 | 2014-06-11 | 三星电子株式会社 | Smart NFC antenna matching network system and user device including the same |
| CN203149603U (en) * | 2013-01-17 | 2013-08-21 | 公安部第三研究所 | Identification reader-writer for T5557 radio frequency cards |
| CN103699918A (en) * | 2013-12-30 | 2014-04-02 | 威海北洋电气集团股份有限公司 | RFID (radio frequency identification) tag reader-writer |
Non-Patent Citations (4)
| Title |
|---|
| 崔晓: "通信电子电路中的LC并联谐振回路", 《现代电子技术》 * |
| 薛涵: "13.56MHz射频识别读卡器芯片接收子系统的设计与实现", 《中国优秀硕士学位论文全文数据库 信息科技辑》 * |
| 谭效武: "基于AT89C52的非接触IC卡读卡器的设计与实现", 《中国优秀硕士学位论文全文数据库 信息科技辑》 * |
| 贾红光: "电磁谐振耦合无线电能传输实验装置的研究", 《中国优秀硕士学位论文全文数据库 工程科技Ⅱ辑》 * |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105225317A (en) * | 2015-10-03 | 2016-01-06 | 上海大学 | A kind of network access control system of multichannel centralized management |
| CN110598498A (en) * | 2019-09-12 | 2019-12-20 | 北京维普无限智能技术有限公司 | Method for improving signal identification capability of non-contact card reader |
| CN110598498B (en) * | 2019-09-12 | 2022-10-25 | 北京维普无限智能技术有限公司 | Method for improving signal identification capability of non-contact card reader |
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| CN104899534B (en) | 2017-12-08 |
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