CN103714374B - The demodulator circuit of A type contactless IC card - Google Patents
The demodulator circuit of A type contactless IC card Download PDFInfo
- Publication number
- CN103714374B CN103714374B CN201210376881.8A CN201210376881A CN103714374B CN 103714374 B CN103714374 B CN 103714374B CN 201210376881 A CN201210376881 A CN 201210376881A CN 103714374 B CN103714374 B CN 103714374B
- Authority
- CN
- China
- Prior art keywords
- pulse width
- signal
- card
- groove signal
- groove
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Landscapes
- Near-Field Transmission Systems (AREA)
Abstract
The invention discloses the demodulator circuit of a kind of A type contactless IC card, including: demodulation module and fixed pulse width circuit, fixed pulse width circuit can export second groove signal less than the pulse-time jitter of the first groove signal of demodulation module output.The present invention can make the pulse width of the groove signal that demodulator circuit exports reduce and fixing, the fluctuation making the pulse width of the groove signal that demodulator circuit exports is minimized, and meets the digital decoding requirement to the fluctuation of the pulse width of the groove signal that demodulator circuit exports.The pulse width of second groove signal of the present invention can directly be determined by current source and electric capacity, the fabrication process condition of A type contactless IC card, operational temperature conditions can be greatly reduced, varied in size by magnetic field and the supply voltage that senses, and the impact that different types of card reader is on the pulse width of groove signal, reduce the fluctuation of the pulse width of groove signal further.
Description
Technical field
The present invention relates to a kind of semiconductor integrated circuit, particularly relate to the demodulator circuit of a kind of A type contactless IC card.
Background technology
A type (type) does carrier wave by radiofrequency signal between contactless IC card and card reader and transmits information.A type noncontact
IC-card itself does not has power supply, and electric energy during its work is provided by the radiofrequency signal of card reader, wherein the radio frequency letter of card reader
Number it is 13.56MHz.When card reader and A type contactless IC card pass data mutually, carrier wave is the radio-frequency carrier of 13.56MHz, signal
Transfer rate has 106kbits/s, 212kbits/s, 424kbits/s, 848k bits/s tetra-kinds respectively.
Wherein, from card reader to A type contactless IC card transmit data time, be use amplitude-shift keying (ASK) method to signal
Being modulated, coded system is Miller (miller) coding synchronizing, improving.Card reader and contactless ic calorie requirement carry out numeral
During the communication of communication i.e. 0,1, on the digital signal modulated of card reader to described radio-frequency carrier signal after can be formed and include groove
(pause) modulated signal of signal, the amplitude of groove (pause) signal is less than the amplitude of radio-frequency carrier, signal transmission rate
Amplitude for groove during 106kbits/s (pause) signal is 0.According to pause signal position in the sequential of modulated signal
Difference represents digital signaling zero or 1, so groove signal is the expression way of data.Modulated signal is defeated by being wirelessly transferred
Entering in contactless IC card, contactless IC card is come this modulated signal by demodulator circuit after receiving this modulated signal by antenna
Being demodulated, demodulating process is divided into analog demodulator and digital demodulation two step, by the analog demodulator of demodulator circuit by modulated signal
In pause signal be demodulated into digital signaling zero or 1, will demodulation after digital signal carry out digital decoding, digital decoding according to
Transmit in the position difference confirmation card reader of 0 in the digital signal of input is data 0 or 1.
As it is shown in figure 1, be existing sequential after card reader to three kinds of analog codecs of A type contactless IC card, i.e. pass through A
After pause signal in modulated signal is demodulated into digital signaling zero or 1 by the analog demodulator of the demodulator circuit of type contactless IC card
Including three sequential, each sequential is corresponding to the transmission cycle of a data bit, and three sequential are defined respectively as:
1, sequential X, this sequential X will produce a groove signal, i.e. at (1/2) × (fc/ transfer rate) × (1/fc) place
At txIt is t that place starts to produce a widthaGroove signal.
2, sequential Y, this sequential Y is i.e. t during whole positionbDo not modulate.
3, sequential Z, during the beginning of this sequential Z period in place, producing a width is taGroove signal.
During for the transfer rate of 848kbits/s, 424kbits/s, 212kbits/s and 106kbits/s, a data
The transmission time Tbit of position, respectively 16,32,64 and 128 clock cycle (clk), wherein 1clk=1/13.56MHz=
73.746nS, transmission time Tbit are shown as t at Fig. 1b。
After the decoding circuit analog codec of existing A type contactless IC card, the pulse width of the groove signal of output is change
, and due to the limitation of digital decoding (i.e. miller signal being decoded) algorithm, under any transfer rate, for groove
The maximum of the pulse width of signal and minima, it is desirable to < (1/2) × Tbit, wherein Tmax represents groove signal to Tmax-Tmin
The maximum of pulse width, Tmin represents the minima of the pulse width of groove signal.
The influence factor of the pulse width of the groove signal of existing A type contactless IC card output includes: A type contactless IC card
Fabrication process condition, the operational temperature conditions of A type contactless IC card, A type contactless IC card varied in size by magnetic field and feel
The many factors such as the card reader that the supply voltage that should arrive, different vendor provide, these influence factors can make the pulse of groove signal
Change width is too big, when pulse width excursion beyond formula Tmax-Tmin < during scope defined in (1/2) × Tbit,
Then can not meet decoding algorithm requirement.
Summary of the invention
The technical problem to be solved is to provide the demodulator circuit of a kind of A type contactless IC card, it is possible to make demodulation
The pulse width of the groove signal of circuit output reduces and fixing, makes the ripple of the pulse width of the groove signal that demodulator circuit exports
Move and be minimized, meet the digital decoding requirement to the fluctuation of the pulse width of the groove signal that demodulator circuit exports.
For solving above-mentioned technical problem, the demodulator circuit of the A type contactless IC card that the present invention provides includes:
Demodulation module, this demodulation module is for being demodulated the input signal of amplitude-shift keying modulation, and can export a number
First groove pulse signal of word；It is positioned at the pulse of described first groove signal of the position the most in the same time of described input signal
Width can change.
Fixed pulse width circuit, the input of this fixed pulse width circuit connects the outfan of described demodulation module, for institute
Stating the first groove signal to carry out processing and export the second groove signal, the fluctuation making the pulse width of described second groove signal is little
Fluctuation in the pulse width of described first groove signal.
Further improving is that the carrier frequency of A type contactless IC card is 13.56MHZ.
Further improving is to be positioned at the arteries and veins of described first groove signal of the position the most in the same time of described input signal
The influence factor rushing width generation change includes: the fabrication process condition of A type contactless IC card, the work of A type contactless IC card
Temperature conditions, being varied in size by magnetic field and the supply voltage sensed, different types of card reader of A type contactless IC card.
Further improving is that described fixed pulse width circuit includes a current source and an electric capacity, by described current source to institute
The charging delay time stating electric capacity determines the pulse width of described second groove signal.
Further improving is that described fixed pulse width circuit also includes:
Nmos pass transistor, the grid of this nmos pass transistor is connected with the outfan of described demodulation module, described NMOS crystal
The source ground of pipe, the drain electrode of described nmos pass transistor connects described current source, the two ends of described electric capacity respectively with described NMOS
The source electrode of crystal is connected with drain electrode.
First phase inverter, the input of this first phase inverter connects the drain electrode of described nmos pass transistor.
Second phase inverter, the input of this second phase inverter connects the outfan of described demodulation module.
NAND gate, two inputs of this NAND gate connect the outfan of described first phase inverter and described second anti-respectively
The outfan of phase device, the outfan of described NAND gate exports described second groove signal.
The present invention is by arranging fixed pulse width circuit in demodulator circuit, it is possible to export more recessed than the first of demodulation module output
The second groove signal that the pulse width of the pulse width of groove signal is less and fixing, relative to existing demodulator circuit, the present invention
The pulse width that can make the groove signal that demodulator circuit exports reduces and fixing, makes the arteries and veins of the groove signal that demodulator circuit exports
The fluctuation rushing width is minimized, and meets digital decoding wanting the fluctuation of the pulse width of the groove signal that demodulator circuit exports
Ask.And the pulse width of second groove signal of the present invention can directly be determined by current source and electric capacity, it is possible to greatly reduce A type non-
Contact the electricity of the read write line of the fabrication process condition of IC-card, the operational temperature conditions of A type contactless IC card, A type contactless IC card
The impact on the pulse width of groove signal of the source voltage, further reduces the fluctuation of the pulse width of groove signal.
Accompanying drawing explanation
With detailed description of the invention, the present invention is described in further detail below in conjunction with the accompanying drawings:
Fig. 1 is existing sequential after card reader to three kinds of analog codecs of A type contactless IC card；
Fig. 2 is embodiment of the present invention electrical block diagram；
Fig. 3 is that in Fig. 2, mode transfer block exports each node waveform figure during the first groove signal.
Detailed description of the invention
As in figure 2 it is shown, be embodiment of the present invention electrical block diagram；The embodiment of the present invention non-to A type from card reader
The carrier wave of the demodulator circuit of contact IC-card is 13.56MHZ radiofrequency signal for the frequency provided by card reader, the data in card reader
Signal is modulated in radiofrequency signal through amplitude-shift keying (ASK) method and is input in the demodulator circuit of A type contactless IC card, warp
The input signal of ASK method modulation includes that, by groove signal, the amplitude of groove signal is less than the amplitude of radio-frequency carrier.According to
Groove signal signal position difference in the sequential of input signal represents digital signaling zero or 1.Embodiment of the present invention A type
The demodulator circuit of contactless IC card is for being simulated demodulation, by groove signal to the groove signal of the input signal of ASK modulation
Being demodulated into digital signaling zero or 1, wherein digital signaling zero is a groove, and the digital signaling zero of analog demodulator or 1 includes such as Fig. 1
Three shown sequential, can obtain in card reader after the digital signaling zero or 1 of analog demodulator is carried out digital demodulation is original
The data signal of input.
The demodulator circuit of embodiment of the present invention A type contactless IC card includes:
Demodulation module 1, this demodulation module 1 is demodulated for the input signal modulating amplitude-shift keying, demodulation module 1
Outfan exports output signal CMPOUT, and this output signal CMPOUT is digital signal, and output signal CMPOUT includes
One groove signal, this first groove signal be the groove signal in input signal is decoded after numeral 0 signal that obtains.Position
Pulse width in described first groove signal of the position the most in the same time of described input signal can change, and produces this change
Influence factor include: the fabrication process condition of A type contactless IC card, the operational temperature conditions of A type contactless IC card, A type are non-
The supply voltage, the different types of card reader such as different vendor that contact being varied in size by magnetic field of IC-card and sense are provided
Card reader.
Fixed pulse width circuit 10, the input of this fixed pulse width circuit 10 connects the outfan of described demodulation module 1, is used for
Described first groove signal is processed and export the second groove signal DEMOUT, makes described second groove signal DEMOUT
The fluctuation of pulse width is less than the fluctuation of the pulse width of corresponding described first groove signal.
Described fixed pulse width circuit 10 includes:
One current source 2, one end of this current source 2 and power vd D connect.
One electric capacity 3, one end of this electric capacity 3 is connected with the other end of described current source 2, the other end ground connection of described electric capacity 3.
Determine the pulse width of described second groove signal DEMOUT to the charging delay time of described electric capacity 3 by described current source 2.
Nmos pass transistor 4, the grid of this nmos pass transistor 4 is connected with the outfan of described demodulation module 1, and described NMOS is brilliant
The source ground of body pipe 4, the drain electrode of described nmos pass transistor 4 connects the other end of current source 2, and the two ends of described electric capacity 3 are respectively
It is connected with drain electrode with the source electrode of described NMOS crystal.
First phase inverter 5, the input of this first phase inverter 5 connects the drain electrode of described nmos pass transistor 4, described first anti-
Input one input signal NETA of the input of phase device 5, outfan export output signal NETB.
Second phase inverter 6, the input of this second phase inverter 6 connects the outfan of described demodulation module 1.Described second anti-
Outfan output signal NETC of phase device 6.
NAND gate 7, two inputs of this NAND gate 7 connect the outfan and described of described first phase inverter 5 respectively
The outfan of two phase inverters 6, the outfan of described NAND gate 7 exports output signal DEMOUT, and described first groove signal
Correspondence, described output signal DEMOUT exports described second groove signal in corresponding time sequence position.
As it is shown on figure 3, be that in Fig. 2, mode transfer block exports each node waveform figure during the first groove signal.Wherein work as output signal
CMPOUT decline be produced as amplitude be 0 for the first groove signal time, described nmos pass transistor 4 closes, and described current source 2 is to institute
State electric capacity 3 and charge so that the input end signal NETA of described first phase inverter 5 slowly rises, until on input end signal NETA
When being raised to the upset point of described first phase inverter 5, output signal NETB produces upset.Output signal NETC is output signal
CMPOUT negates, and output signal NETB and output signal NETC obtain output signal DEMOUT of burst pulse i.e. after negating
Second groove signal, it can be seen that the pulse width of the second groove signal is determined by current source and electric capacity, and the second groove
Signal is less than the pulse width of the pulse width of the first groove signal and fixing, it is possible to greatly reduce A type contactless IC card
Fabrication process condition, the operational temperature conditions of A type contactless IC card, A type contactless IC card the supply voltage of read write line to recessed
The impact of the pulse width of groove signal, makes the fluctuation of the pulse width of the groove signal that demodulator circuit exports be minimized, meets
The digital decoding requirement to the fluctuation of the pulse width of the groove signal that demodulator circuit exports.
Above by specific embodiment, the present invention is described in detail, but these have not constituted the limit to the present invention
System.Without departing from the principles of the present invention, those skilled in the art it may also be made that many deformation and improves, and these also should
It is considered as protection scope of the present invention.
Claims (4)
1. the demodulator circuit of an A type contactless IC card, it is characterised in that including:
Demodulation module, this demodulation module is for being demodulated the input signal of amplitude-shift keying modulation, and can export a numeral
First groove pulse signal；It is positioned at the pulse width of described first groove signal of the position the most in the same time of described input signal
Can change；
Fixed pulse width circuit, the input of this fixed pulse width circuit connects the outfan of described demodulation module, for described the
One groove signal carries out processing and export the second groove signal, makes the fluctuation of pulse width of described second groove signal less than institute
State the fluctuation of the pulse width of the first groove signal；
Described fixed pulse width circuit includes a current source and an electric capacity, by described current source to the charging delay time of described electric capacity
Determine the pulse width of described second groove signal.
2. the demodulator circuit of A type contactless IC card as claimed in claim 1, it is characterised in that: the carrier wave of A type contactless IC card
Frequency is 13.56MHZ.
3. the demodulator circuit of A type contactless IC card as claimed in claim 1, it is characterised in that: it is positioned at described input signal
The influence factor of the pulse width generation change of described first groove signal of position includes the most in the same time: A type contactless ic
The fabrication process condition of card, the operational temperature conditions of A type contactless IC card, being varied in size by magnetic field of A type contactless IC card
And the supply voltage sensed, different types of card reader.
4. the demodulator circuit of A type contactless IC card as claimed in claim 1, it is characterised in that: described fixed pulse width circuit is also
Including:
Nmos pass transistor, the grid of this nmos pass transistor is connected with the outfan of described demodulation module, described nmos pass transistor
Source ground, the drain electrode of described nmos pass transistor connects described current source, the two ends of described electric capacity respectively with described NMOS crystal
Source electrode with drain electrode be connected；
First phase inverter, the input of this first phase inverter connects the drain electrode of described nmos pass transistor；
Second phase inverter, the input of this second phase inverter connects the outfan of described demodulation module；
NAND gate, two inputs of this NAND gate connect the outfan of described first phase inverter and described second phase inverter respectively
Outfan, the outfan of described NAND gate exports described second groove signal.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201210376881.8A CN103714374B (en) | 2012-09-28 | 2012-09-28 | The demodulator circuit of A type contactless IC card |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201210376881.8A CN103714374B (en) | 2012-09-28 | 2012-09-28 | The demodulator circuit of A type contactless IC card |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN103714374A CN103714374A (en) | 2014-04-09 |
| CN103714374B true CN103714374B (en) | 2016-08-17 |
Family
ID=50407330
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201210376881.8A Active CN103714374B (en) | 2012-09-28 | 2012-09-28 | The demodulator circuit of A type contactless IC card |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN103714374B (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105577149B (en) * | 2014-10-09 | 2018-08-14 | 上海华虹集成电路有限责任公司 | Waveform shaping circuit after card communication demodulation in 14443 agreements of ISO/IEC |
| JP6450184B2 (en) * | 2014-12-24 | 2019-01-09 | エイブリック株式会社 | Overheat detection circuit and semiconductor device |
| CN106228095B (en) * | 2016-07-19 | 2019-03-29 | 天津市炳华节能技术有限公司 | A kind of implementation method of the automatic card seeking of radio-frequency card |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1805416A (en) * | 2006-01-20 | 2006-07-19 | 清华大学 | Comparison and decision circuit in amplitude keying signal demodulation circuit module |
| CN101615260A (en) * | 2008-06-27 | 2009-12-30 | 株式会社瑞萨科技 | SIC (semiconductor integrated circuit), the IC-card that this circuit is installed and this IC-card method of operating |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0991072A (en) * | 1995-09-22 | 1997-04-04 | Canon Inc | Data processor and its controlling method |
| DK2400665T3 (en) * | 2010-06-22 | 2016-03-29 | Oticon As | High voltage-oscillation input / output that is activated in a standard IC process using passive impedance transformation |
-
2012
- 2012-09-28 CN CN201210376881.8A patent/CN103714374B/en active Active
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1805416A (en) * | 2006-01-20 | 2006-07-19 | 清华大学 | Comparison and decision circuit in amplitude keying signal demodulation circuit module |
| CN101615260A (en) * | 2008-06-27 | 2009-12-30 | 株式会社瑞萨科技 | SIC (semiconductor integrated circuit), the IC-card that this circuit is installed and this IC-card method of operating |
Also Published As
| Publication number | Publication date |
|---|---|
| CN103714374A (en) | 2014-04-09 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN102859841B (en) | Current-collecting device and electrical power transmission system | |
| CN101593285B (en) | Transponder, interrogator, and communication device | |
| CN101826898B (en) | Communication device and communication method | |
| CN103117775A (en) | Varying load modulation in an NFC-enabled device over a range of field strength | |
| CN103714374B (en) | The demodulator circuit of A type contactless IC card | |
| CN207369033U (en) | NFC interface with energy management functionality | |
| CN105160389A (en) | Passive ultrahigh-frequency RFID tag for temperature alarming | |
| CN102270313B (en) | Power on reset circuit of RFID (Radio Frequency Identification) tag | |
| CN102831448B (en) | A kind of rfid device | |
| CN109416751A (en) | RF energy collection device and its application method | |
| CN103870868A (en) | Demodulation circuit of non-contact IC card | |
| US20130225076A1 (en) | Recharge of an nfc device | |
| CN103065188A (en) | Decoding circuit of non-contact integrated circuit (IC) card | |
| CN202736098U (en) | Non-contact IC card radio frequency interface circuit, non-contact IC card, non-contact near-field communication system | |
| CN101739542B (en) | Near field communication radio frequency interface integrated circuit | |
| CN105635011A (en) | Signal demodulation apparatus | |
| CN105930130B (en) | A kind of true random number generation device suitable for RFID reader | |
| CN201307289Y (en) | Near field communication radio-frequency interface integrated circuit | |
| CN201111183Y (en) | Electric cipher key | |
| CN205160520U (en) | Passive NFC communication interface with independent energy receiving antenna | |
| CN104346645B (en) | The demodulator circuit of contactless IC card | |
| CN204302407U (en) | A kind of super high band RFID test macro | |
| CN207637180U (en) | A kind of near-field communication front end hardware circuit, safety chip, dynamic token and contact type intelligent card | |
| CN103001901B (en) | Integrated circuit high-speed digital interface module based on modified difference pulse code modulation (MDPCM) | |
| CN205721741U (en) | A kind of true random number generation device being applicable to RFID reader |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant |