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US5753902A
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IC card, reader/writer
Assignee: Renesas Design Corp
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Filing: 1996-11-01
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Granted: 1998-05-19
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Expires: 2016-11-01
Abstract
Abstract A noncontact IC card, a card reader/writer, and a card system, for surely detecting a start flag, thereby reducing a communication error rate and achieving higher communication reliability. The noncontact IC card has a control unit, which includes a CPU, ROM, RAM, etc., and it further has a 1-bit flip-flop (F/F) connected between a receive circuit and the control unit. According to a program of the control unit, data are received one bit at a time, and a UART is set ready for receiving when a bit pattern of the start flag is detected. A card reader/writer is equipped with a control unit which includes a CPU, ROM, RAM, etc. The control unit inserts 1-byte dummy data "00 H " between a trigger signal and the start flag at the time of transmission. A card system has a card reader/writer and a noncontact IC card. The card reader/writer is provided with a control unit, a transmitting antenna, which includes a series resonance circuit, and a switching circuit, which is connected between a receiving antenna and a receive circuit. Further, the noncontact IC card is provided with a 1-bit flip-flop (F/F), which is connected between the receive circuit and the control unit.
Inventors
- 👤 Shuzo Fujioka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 17:26
CPC Classifications
G; G06; G06K; G06K7/00; G06K7/10; G06K7/10009; G06K7/10316; G06K17/00; G06K19/00; G06K19/06; G06K19/067; G06K19/07; G06K19/0723; G06K7/0008; G06K7/10297
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
111 words
A card reader/writer comprising: a UART for converting a digital signal in serial form into parallel form and vice versa; a send circuit for modulating a digital signal in serial form from said UART and converting it into a send electrical signal; a transmitting antenna for transmitting the send electrical signal as a radio wave; a receiving antenna for converting a received radio wave into a received electrical signal; a receive circuit for demodulating a received electrical signal and converting it into a digital signal; a control unit for controlling said card reader/writer; and a switching circuit connected between said receiving antenna and said receive circuit for disconnecting them during transmission.
Claim 2
Dependent Claim
111 words
A card reader/writer comprising: a UART for converting a digital signal in serial form into parallel form and vice versa; a send circuit for modulating a digital signal in serial form from said UART and converting it into a send electrical signal; a transmitting antenna for transmitting the send electrical signal as a radio wave; a receiving antenna for converting a received radio wave into a received electrical signal; a receive circuit for demodulating a received electrical signal and converting it into a digital signal; a control unit for controlling said card reader/writer; and a switching circuit connected between said receiving antenna and said receive circuit for disconnecting them during transmission.
Claim 3
Dependent Claim
33 words
The card reader/writer according to claim 1, wherein said switching circuit disconnects said receiving antenna and said receive circuit with a timing that prevents switching noise from being transmitted to said receive circuit.
Claim 4
Dependent Claim
117 words
A card reader/writer comprising: a UART for converting a digital signal in serial form into parallel form and vice versa; a send circuit for modulating a digital signal in serial form from said UART and converting it into a send electrical signal; a transmitting antenna for transmitting the send electrical signal as a radio wave; a receiving antenna comprising a parallel resonance circuit and a switching circuit set to ON to prevent said parallel resonance circuit from resonating during transmission and for converting a received radio wave into a received electrical signal; a receive circuit for demodulating a received electrical signal and converting it into a digital signal; and a control unit for controlling said card reader/writer.
Claim 5
Dependent Claim
117 words
A card reader/writer comprising: a UART for converting a digital signal in serial form into parallel form and vice versa; a send circuit for modulating a digital signal in serial form from said UART and converting it into a send electrical signal; a transmitting antenna for transmitting the send electrical signal as a radio wave; a receiving antenna comprising a parallel resonance circuit and a switching circuit set to ON to prevent said parallel resonance circuit from resonating during transmission and for converting a received radio wave into a received electrical signal; a receive circuit for demodulating a received electrical signal and converting it into a digital signal; and a control unit for controlling said card reader/writer.
Claim 6
Dependent Claim
34 words
The card reader/writer according to claim 3, wherein said transmitting antenna comprises a parallel resonance circuit and a second switching circuit set to ON to prevent said parallel resonance circuit from resonating during receiving.
Claim 7
Dependent Claim
16 words
The card reader/writer according to claim 3, wherein said transmitting antenna is a series resonance circuit.
Claim 8
Dependent Claim
119 words
A card reader/writer comprising: a UART for converting a digital signal in serial form into parallel form and vice versa; a send circuit for modulating a digital signal in serial form from said UART and converting it into a send electrical signal; a transmitting antenna comprising a parallel resonance circuit and a switching circuit set to ON to prevent said parallel resonance circuit from resonating during receiving and for transmitting the send electrical signal as a radio wave during transmission; a receiving antenna for converting a received radio wave into a received electrical signal; a receive circuit for demodulating a received electrical signal and converting it into a digital signal; and a control unit for controlling said card reader/writer.
Claim 9
Dependent Claim
119 words
A card reader/writer comprising: a UART for converting a digital signal in serial form into parallel form and vice versa; a send circuit for modulating a digital signal in serial form from said UART and converting it into a send electrical signal; a transmitting antenna comprising a parallel resonance circuit and a switching circuit set to ON to prevent said parallel resonance circuit from resonating during receiving and for transmitting the send electrical signal as a radio wave during transmission; a receiving antenna for converting a received radio wave into a received electrical signal; a receive circuit for demodulating a received electrical signal and converting it into a digital signal; and a control unit for controlling said card reader/writer.
Claim 10
Dependent Claim
99 words
A card reader/writer comprising: a UART for converting a digital signal in serial form into parallel form and vice versa; a send circuit for modulating a digital signal in serial form from said UART and converting it into a send electrical signal; a transmitting antenna comprising a series resonance circuit for transmitting the send electrical signal as a radio wave; a receiving antenna for converting a received radio wave into a received electrical signal; a receive circuit for demodulating a received electrical signal and converting it into a digital signal; and a control unit for controlling said card reader/writer.
Claim 11
Dependent Claim
99 words
A card reader/writer comprising: a UART for converting a digital signal in serial form into parallel form and vice versa; a send circuit for modulating a digital signal in serial form from said UART and converting it into a send electrical signal; a transmitting antenna comprising a series resonance circuit for transmitting the send electrical signal as a radio wave; a receiving antenna for converting a received radio wave into a received electrical signal; a receive circuit for demodulating a received electrical signal and converting it into a digital signal; and a control unit for controlling said card reader/writer.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2001-05-18 | 2001-11-17 | 2002-05-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-05-18 | 2005-11-17 | 2006-05-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-05-18 | 2009-11-17 | 2010-05-19 | $7700.00 | Window Closed / Lapsed |