WO1998043200A1 - Transaction system - Google Patents
Transaction system Download PDFInfo
- Publication number
- WO1998043200A1 WO1998043200A1 PCT/GB1998/000814 GB9800814W WO9843200A1 WO 1998043200 A1 WO1998043200 A1 WO 1998043200A1 GB 9800814 W GB9800814 W GB 9800814W WO 9843200 A1 WO9843200 A1 WO 9843200A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- token
- transaction system
- carrier
- clock
- data
- Prior art date
Links
Classifications
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
- G06K7/00—Methods or arrangements for sensing record carriers, e.g. for reading patterns
- G06K7/0008—General problems related to the reading of electronic memory record carriers, independent of its reading method, e.g. power transfer
Definitions
- This invention relates to a transaction system in which a portable token, for example a
- card is used in conjunction with a device, often termed a reader or terminal, to perform
- the invention also relates to the portable token itself.
- invention is particularly, but not exclusively, related to a portable token of credit card
- Such a token is commonly referred to as a "smart card”.
- Certain portable tokens must be in physical contact with a terminal in order to operate. These are referred to as contact tokens. Other portable tokens which can operate without being in physical contact with a terminal are referred to as contactless tokens.
- Contactless tokens work on, or close to, a terminal which provides power. This power is supplied via a RF (radio frequency) induction field which is referred to as a carrier. Power is transferred from an aerial in the terminal to an aerial on the token.
- RF radio frequency
- both the terminal and the token each have
- a single aerial each of which may comprise a coil having one or more turns.
- the terminal modulates it onto the carrier.
- the token switches an impedance to modulate the amplitude of the carrier at the terminal as the token draws extra power from the terminal
- the token also requires a clock which is used in the token to provide timing information for the processor means to carry out instructions and send data. It is known in
- contactless tokens for the clock to be derived either internally from a frequency source such as a crystal or ceramic resonator, or from the carrier.
- a frequency source such as a crystal or ceramic resonator
- the carrier determines the frequency of the clock.
- the clock frequency it is usual for the clock frequency to be either a divisor of the carrier frequency (for example, a high carrier frequency divided by flip flops and logic operations) or a multiple of the carrier frequency (for example, a lower carrier frequency multiplied by a phase lock loop).
- frequency sources may be generated within
- carrier frequency is limited to be within a relatively narrow operating window in order
- the clock frequency in the token is determined by the carrier frequency, the clock frequency in the token is
- GB 2 207 790 B discloses a transaction system in which data is transmitted by interruption of a carrier. Since the carrier is used directly to provide a clock for a token, interruption of the carrier also interrupts the clock and so means is provided in the token to provide a clock signal which is available during times in which the carrier is being interrupted. Since the carrier is also used as a source of power to power the token, a power storage circuit is needed in the token to prevent interruption of power supply to the token.
- WO 88/02171 discloses a transaction system in which data and clock signals sent by a
- a typical system is designed to have
- Another problem is caused by the need for tokens to communicate with hosts at faster
- the token is used as a travel token in a public
- a transaction between the token and a host has to occur in less
- the vertical line 2 represents the carrier frequency and its amplitude. It is centred in the operating window 4 imposed by the permitted RFI limit 6.
- index is (A-B)/(A+B) which is a relative quantity and is usually expressed as a
- the carrier is modulated by ASK with a
- the invention provides a transaction system comprising a terminal the terminal being capable of sending data to the token during a transaction the
- clock signal being a tone on a continuous carrier in which the clock signal is
- the invention provides a method of sending a clock signal
- the invention provides a transaction system for carrying out
- the clock rates are significantly different.
- the invention may provide a method according to its third aspect.
- the invention provides a contactless token for use with the
- tone simply refers to a signal having characteristics such as amplitude
- the tone is convenient for the tone to be cyclic. Since the tone is independent of the carrier, it is possible to reduce the absolute power level of the carrier without affecting
- the tone can be used by the token to generate a clock for itself.
- the tone can be used by the token to generate a clock for itself.
- data may also be sent by the terminal and/or the token.
- the data may be information which is needed to conduct a transaction and may include
- the carrier undergoes a double modulation in which the carrier is modulated
- the tone is modulated by the data to be sent in order to produce a modulated
- ASK, PSK or FSK may be used to modulate the tone by the data (which may be
- PSK is preferred.
- the modulated tone may then be used to modulate the carrier
- AM Amplitude modulation
- the tone may be generated by a clock supplied by a host.
- the host clock supplied by a host.
- the tone may be divided by a factor of N to provide the tone.
- the factor N is 8.
- the host clock may be multiplied by a factor N to provide the tone.
- the factor N may be multiplied by a factor N to provide the tone.
- N is chosen to provide a tone and thus a clock in the token appropriate to an operation
- the shape of the tone is sinusoidal. However, it could be square, triangular
- the carrier is continuous during a communication procedure, such as a
- the token has a single inductive coil aerial.
- the modulated carrier may be demodulated to provide the modulated tone.
- Demodulation of the modulated tone may provide the data and the tone.
- the clock signal for the token may be extracted from the tone by using a phase lock loop
- the contactless token can be provided with a clock operating at the
- the clock is independent of the carrier and may be varied as desired.
- the terminal and the token can operate and communicate at standard speeds
- carrier frequencies may be chosen to take advantage of locally available operating windows determined by RFI limits.
- the data can modulate the tone either strongly or weakly without the RFI limits for the carrier being exceeded.
- Figure 1 shows a schematic representation of a frequency spectrum generated by
- Figure 2 shows a schematic representation of modulation
- FIG 3 shows a schematic representation of a transaction system
- Figure 4 shows steps in the modulation of a carrier
- Figure 5 shows steps in demodulation of the carrier to obtain a clock signal and a data
- Figures 1 and 2 have already been discussed in the foregoing.
- Figure 3 shows a
- a host supplies the terminal 12 with a clock signal 16 which is sent to
- the clock signal 16 is divided by N, which is typically eight, to produce
- tone generation This step, referred to as tone generation, is shown in Figure 4(a).
- tone signal 20 is supplied to a first modulator 22 where it is modulated by data 24 to
- tone modulation This step, referred to as tone modulation, is shown
- ASK or FSK may be used.
- the data modulated tone 26 is used to modulate
- a carrier signal 28 in a second modulator 30 to produce a modulated carrier signal 32.
- modulation is typically used to modulate the carrier although angular modulation
- the carrier is modulated by the
- the modulated carrier signal 32 is amplified by an amplifier 34 and then used to drive an induction coil 36 which generates the RF induction field of the terminal 12.
- the RF induction field induces in an induction coil 42 in the card 14 a signal 40
- carrier signal occurs in separate parts of the card with a rectifier being used to extract
- the demodulator may be combined because the circuitry which serves as the rectifier
- Data 50 and clock 52 information can then be extracted from signal 48 by known
- phase locked loop (PLL) arrangement 54 This is
- arrangement 54 extracts the data and also multiplies the tone by N to provide a
- tone demodulation is shown in Figure 5(b). In this way the card 14 can receive the
- the PLL arrangement 54 may be configured such that it can extract both the data and the clock thus removing the need for a further step such as multiplication.
- the PLL may be configured such that it can extract both the data and the clock thus removing the need for a further step such as multiplication.
- phase detector receives an incoming signal (the data modulated tone) and
- the phase detector outputs a signal which is sent to a low pass filter.
- a signal may be produced which has a trace signal representative of data.
- This trace signal may be detected and used to generate the data.
- the terminal at which the token will work. If necessary the terminal may adjust its power
- a clock of 1 MHz is supplied to the token so that the token operates at a relatively low
- clock speed allows non-demanding transactions to take place such as hand-shake or
- the clock can be switched to a relatively higher rate of about 5MHz to allow more complex operations such as a full challenge response encryption
- a carrier frequency may be used. Therefore, a carrier may be chosen having a frequency
- a tone is present on the carrier. If the tone is removed
Landscapes
- Engineering & Computer Science (AREA)
- Artificial Intelligence (AREA)
- Computer Vision & Pattern Recognition (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Theoretical Computer Science (AREA)
- Near-Field Transmission Systems (AREA)
- Digital Transmission Methods That Use Modulated Carrier Waves (AREA)
Abstract
Description
Claims
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
AU64145/98A AU6414598A (en) | 1997-03-22 | 1998-03-18 | Transaction system |
EP98909667A EP1016025A1 (en) | 1997-03-22 | 1998-03-18 | Transaction system |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB9706019.8 | 1997-03-22 | ||
GB9706019A GB2323460A (en) | 1997-03-22 | 1997-03-22 | Card reading system |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1998043200A1 true WO1998043200A1 (en) | 1998-10-01 |
Family
ID=10809732
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/GB1998/000814 WO1998043200A1 (en) | 1997-03-22 | 1998-03-18 | Transaction system |
Country Status (4)
Country | Link |
---|---|
EP (1) | EP1016025A1 (en) |
AU (1) | AU6414598A (en) |
GB (1) | GB2323460A (en) |
WO (1) | WO1998043200A1 (en) |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE10050878B4 (en) * | 2000-10-13 | 2012-07-12 | Atmel Automotive Gmbh | Method for transmitting a plurality of information symbols |
Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4654658A (en) * | 1984-08-03 | 1987-03-31 | Walton Charles A | Identification system with vector phase angle detection |
EP0270274A2 (en) * | 1986-12-05 | 1988-06-08 | Meridian Micro-Systems Limited | Transponder and interrogator |
US5453747A (en) * | 1993-06-28 | 1995-09-26 | Texas Instruments Deutschland Gmbh | Transponder systems for automatic identification purposes |
US5504485A (en) * | 1994-07-21 | 1996-04-02 | Amtech Corporation | System for preventing reading of undesired RF signals |
US5585617A (en) * | 1994-07-13 | 1996-12-17 | Mitsubishi Denki Kabushiki Kaisha | Non-contact IC card communicating at multiple frequencies |
US5591951A (en) * | 1995-10-12 | 1997-01-07 | The Regents Of The University Of California | System and method for simultaneously collecting serial number information from numerous identity tags |
-
1997
- 1997-03-22 GB GB9706019A patent/GB2323460A/en not_active Withdrawn
-
1998
- 1998-03-18 EP EP98909667A patent/EP1016025A1/en not_active Withdrawn
- 1998-03-18 AU AU64145/98A patent/AU6414598A/en not_active Abandoned
- 1998-03-18 WO PCT/GB1998/000814 patent/WO1998043200A1/en not_active Application Discontinuation
Patent Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4654658A (en) * | 1984-08-03 | 1987-03-31 | Walton Charles A | Identification system with vector phase angle detection |
EP0270274A2 (en) * | 1986-12-05 | 1988-06-08 | Meridian Micro-Systems Limited | Transponder and interrogator |
US5453747A (en) * | 1993-06-28 | 1995-09-26 | Texas Instruments Deutschland Gmbh | Transponder systems for automatic identification purposes |
US5585617A (en) * | 1994-07-13 | 1996-12-17 | Mitsubishi Denki Kabushiki Kaisha | Non-contact IC card communicating at multiple frequencies |
US5504485A (en) * | 1994-07-21 | 1996-04-02 | Amtech Corporation | System for preventing reading of undesired RF signals |
US5591951A (en) * | 1995-10-12 | 1997-01-07 | The Regents Of The University Of California | System and method for simultaneously collecting serial number information from numerous identity tags |
Also Published As
Publication number | Publication date |
---|---|
GB9706019D0 (en) | 1997-05-07 |
AU6414598A (en) | 1998-10-20 |
GB2323460A (en) | 1998-09-23 |
EP1016025A1 (en) | 2000-07-05 |
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