Non-contact IC card communicating at multiple frequencies
First Claim
Patent Images
1. A non-contact IC card for communication at a plurality of frequencies comprising:
- a battery serving as a power supply;
data processing and storage means for processing and storage of data;
a frequency-variable antenna circuit for switching communication frequency, said antenna circuit receiving electromagnetic waves from an external source, converting them into a received electrical signal, and converting an internally generated electrical signal into electromagnetic waves for transmission;
clock generation means for generating a clock signal at a reference frequency;
variable communication clock generation means for dividing the reference frequency of the clock signal to selectively generate communication clock signals at a plurality of different frequencies respectively corresponding to communication frequencies of said antenna circuit; and
communication control means connected between said antenna circuit and said data processing and storage means for converting a received signal into data and data to be transmitted into a transmission signal in accordance with the communication clock signals from said variable communication clock generation means.
1 Assignment
0 Petitions
Accused Products
Abstract
A non-contact IC card capable of communicating with external equipment at various communication frequencies. An antenna circuit of variable frequency and a frequency switching circuit for supplying communication clock signals of variable frequency to a modulator-demodulator circuit are provided so that communication is performed by switching a constant of the antenna circuit and the frequency of the communication clock signal generated from the frequency switching circuit in accordance with the frequency of external equipment with which communication is effected.
42 Citations
4 Claims
-
1. A non-contact IC card for communication at a plurality of frequencies comprising:
-
a battery serving as a power supply; data processing and storage means for processing and storage of data; a frequency-variable antenna circuit for switching communication frequency, said antenna circuit receiving electromagnetic waves from an external source, converting them into a received electrical signal, and converting an internally generated electrical signal into electromagnetic waves for transmission; clock generation means for generating a clock signal at a reference frequency; variable communication clock generation means for dividing the reference frequency of the clock signal to selectively generate communication clock signals at a plurality of different frequencies respectively corresponding to communication frequencies of said antenna circuit; and communication control means connected between said antenna circuit and said data processing and storage means for converting a received signal into data and data to be transmitted into a transmission signal in accordance with the communication clock signals from said variable communication clock generation means. - View Dependent Claims (2, 3, 4)
-
Specification