Data communication equipment, data communication system, and data communication method

• US 6,654,466 B1
• Filed: 10/14/1999
• Issued: 11/25/2003
• Est. Priority Date: 04/17/1997
• Status: Expired due to Fees

• Current Assignee: ROHM Co., Ltd.
• Original Assignee: ROHM Co., Ltd.
• Inventors: Ikefuji, Yoshihiro, Yoshioka, Satoshi
• Primary Examiner(s): Peeso, Thomas R.
• Application Number:
  US09/402,484
• Time in Patent Office: 1,503 Days
• Field of Search: 380/270, 380/255
• US Class Current: 380/270
• CPC Class Codes: G06K 19/0723 the record carrier comprising an arrangement for non-contact communication, e.g. wireless communication circuits on transponder cards, non-contact smart cards or RFIDs

Abstract

Data communication means (82) performs data communication and power transmission by utilizing electromagnetic waves. Conversion method designating means (88) is provided with output value measuring means (52) which measures the magnitude of the fluctuating output of a resonance circuit (40), and conversion method select means (100) which selects a conversion method to be executed in accordance with the obtained magnitude of the output of the resonance circuit (40). Data converting means (84) is provided with three conversion methods and performs conversion between original data and processed data by executing conversion in accordance with one of the conversion methods designated by the select means (100). The safety on security can thus be improved with a simple constitution.

Claims

1. A data communication apparatus, comprising:

data communication means (82) for performing communication of processed data with another data communication apparatus (90);

conversion method designating means (88) for selecting and designating one of a plurality of conversion methods for conversion between original data and the processed data as a conversion method to be executed, corresponding to a prescribed condition that may be altered and can be commonly recognized with said another data communication apparatus; and

data converting means (84) for converting the processed data obtained from said data communication means to the original data or converting the original data to the processed data for application to said data communication means, in accordance with the conversion method designated by said conversion method designating means;

said data communication apparatus performing the conversion between the original data and the processed data in accordance with the same conversion method as used in said another data communication apparatus.

2. The data communication apparatus according to claim 1, wherein said data communication apparatus is capable of performing data communication or power transmission by electrically contacting with said another data communication apparatus.

3. The data communication apparatus according to claim 1, wherein

said data communication apparatus is capable of performing data communication or power transmission in a non-contact manner with said another data communication apparatus utilizing electromagnetic waves, and

said conversion method designating means designates said conversion method to be executed corresponding to a prescribed characteristic of said electromagnetic waves that may be altered and can be commonly recognized with said another data communication apparatus.

4. The data communication apparatus according to claim 3, wherein said conversion method designating means designates said conversion method to be executed corresponding to transmission intensity of the electromagnetic waves.

5. The data communication apparatus according to claim 4, wherein

said data communication means includes a resonance circuit (40) having an antenna for performing data communication or power transmission utilizing the electromagnetic waves, and

said conversion method designating means measures magnitude of output of the resonance circuit corresponding to a level of the electromagnetic waves, and designates said conversion method to be executed corresponding to the measured magnitude of the output of the resonance circuit.

6. The data communication apparatus according to claim 5, wherein said conversion method designating means includes

reference voltage generating means (50) for obtaining a constant reference voltage regardless of voltage fluctuation appealing in said resonance circuit,

output value measuring means (52) for measuring the magnitude of the output of the resonance circuit based on the reference voltage obtained by said reference voltage generating means, and

conversion method select means (100) for selecting said conversion method to be executed corresponding to the magnitude of the output of the resonance circuit obtained by said output value measuring means.

7. The data communication apparatus according to claim 3, wherein said conversion method designating means designates said conversion method to be executed corresponding to a frequency of the electromagnetic waves.

8. The data communication apparatus according to claim 7, wherein

said data communication means includes a resonance circuit having an antenna for performing data communication or power transmission utilizing the electromagnetic waves and having a resonance frequency that can be switched by switching means, and

said conversions system designating means includes resonance frequency setting means that uses said switching means to set the resonance frequency of the resonance circuit to a favorable resonance frequency corresponding to the frequency of said electromagnetic waves.

9. The data communication apparatus according to claim 8, wherein

said conversion method designating means includes

frequency detecting means (102) for detecting the frequency of the electromagnetic waves and

conversion method select means (100) for selecting said conversion method to be executed corresponding to the frequency of the electromagnetic waves detected by the frequency detecting means, and

said resonance frequency setting means sets the resonance frequency of the resonance circuit based on the frequency of the electromagnetic waves detected by said frequency detecting means.

10. The data communication apparatus according to claim 7, wherein said data communication apparatus is capable of either

receiving, from said another data communication apparatus, the electromagnetic waves that are utilized for both the data communication and the power transmission, or

receiving, from said another data communication apparatus, both of the electromagnetic waves utilized for the data communication and the electromagnetic waves utilized for the power transmission different in frequency from the electromagnetic waves utilized for the data communication.

11. The data communication apparatus according to claim 7, wherein said data communication apparatus is capable of either

sending, with respect to said another data communication apparatus, electromagnetic waves to be used for both the data communication and the power transmission, or

sending, to said another data communication apparatus, both of the electromagnetic waves to be used for the data communication and the electromagnetic waves to be used for the power transmission with a frequency different from the frequency of said electromagnetic waves to be used for the data communication.

12. The data communication apparatus according to claim 7, wherein said data converting means prepares as the conversion method for conversion between the original data and the processed data, at least two conversion methods including the following systems to be used independently or as a combination thereof:

(a1) a dummy data inserting system in which dummy data are inserted between the original data to obtain the processed data,

(a2) a bit inverting system in which a prescribed bit of the original data is inverted to obtain the processed data, and

(a3) a data dividing system in which the original data are divided to obtain the process data.

13. The data communication apparatus according to claim 7, wherein

said data communication apparatus is either one of an interrogator or a responsor of an IC card communication system, and

said another data communication apparatus is the other one of the interrogator or the responsor of the IC card communication system.

14. The data communication apparatus according to claim 8, wherein said resonance frequency setting means receives an output signal from the resonance circuit at each switched state while the resonance frequency of said resonance circuit is being switched using said switching means, and sets the switched state of the switching means such that a desirable output signal can be obtained.

15. The data communication apparatus according to claim 8, wherein said switching means includes a plurality of transistors.

16. The data communication apparatus according to claim 8, wherein said resonance circuit is able to use the switching means to select capacitance coupled to the antenna.

17. The data communication apparatus according to claim 8, wherein said resonance circuit uses the switching means to selectively change inductance of the antenna connected to a capacitor.

18. The data communication apparatus according to claim 14, wherein said resonance frequency setting means includes

judgement means (44) for obtaining a voltage or a current appearing in said resonance circuit at each switched state while sequentially switching the switched states of said resonance circuit, and obtaining a favorable switched state of the switching means with which a desirable voltage or current is obtained, and

switched state storing means (46) for storing the favorable switched state obtained by said judgement means.

19. The data communication apparatus according to claim 18, wherein said judgement means includes

reference voltage generating means (50) for obtaining a constant reference voltage regardless of voltage fluctuation appearing in said resonance circuit,

output value measuring means (52) for measuring magnitude of output of said resonance circuit at each switched state based on the reference voltage from the reference voltage generating means, and

state determination means (56) for determining the favorable switched state based on the magnitude of the output obtained by said output value measuring means.

20. The data communication apparatus according to claim 18, wherein

said judgement means further includes output storing means (54) for storing the output value of the resonance circuit corresponding to each switched state of the switching means, by relating the output value to each switched state, and

said state determination means determines the favorable switched state based on the output value stored in said output value storing means.

21. The data communication apparatus according to claim 18, wherein said judgement means selects a switched state corresponding to the largest output value as the favorable switched state.

22. The data communication apparatus according to claim 18, wherein said judgement means receives the output value every time the switched state is switched sequentially, and when receiving an output value that exceeds a prescribed threshold value, selects the relevant switched state as the favorable switched state.

23. The data communication apparatus according to claim 14, wherein said conversion method designating means includes conversion method select means for selecting said conversion method to be executed corresponding to the favorable resonance frequency of said resonance circuit obtained by said resonance frequency setting means.

24. The data communication apparatus according to claim 14, wherein said conversion method designating means includes

frequency detecting means (102) for detecting the frequency of said electromagnetic waves obtained via said resonance circuit set at the favorable resonance frequency by said resonance frequency setting means, and

conversion method select means (100) for selecting said conversion method to be executed corresponding to the frequency of the electromagnetic waves detected by said frequency detecting means.

25. The data communication apparatus according to claim 3, wherein said data communication apparatus is capable of either

receiving, from said another data communication apparatus, the electromagnetic waves that are utilized for both the data communication and the power transmission, or

receiving, from said another data communication apparatus, both of the electromagnetic waves utilized for the data communication and the electromagnetic waves utilized for the power transmission different in frequency from the electromagnetic waves utilized for the data communication.

26. The data communication apparatus according to claim 25, wherein

said data communication apparatus is a data communication apparatus having no power supply source provided therein, that is capable of receiving, from said another data communication apparatus, both of the electromagnetic waves utilized for data communication and having a variable frequency and the electromagnetic waves utilized for power transmission and having a fixed frequency that is different from the frequency of said electromagnetic waves utilized for the data communication, and

said conversion method designating means designates said conversion method to be executed corresponding to the frequency of the electromagnetic waves utilized for the data communication.

27. The data communication apparatus according to claim 25, wherein

said data communication apparatus is a data communication apparatus capable of receiving, from said another data communication apparatus, both of said electromagnetic waves utilized for the data communication and said electromagnetic waves utilized for the power transmission,

either one of said electromagnetic waves utilized for the data communication and said electromagnetic waves utilized for the power transmission being electromagnetic waves having a fixed frequency, and the other one being electromagnetic waves having a variable frequency, and

said conversion method designating means detects the frequency of the electromagnetic waves having the variable frequency based on the frequency of the electromagnetic waves having the fixed frequency, and designates said conversion method to be executed corresponding to the detected frequency.

28. The data communication apparatus according to claim 3, wherein said data communication apparatus is capable of either

sending, with respect to said another data communication apparatus, electromagnetic waves to be used for both the data communication and the power transmission, or

sending, to said another data communication apparatus, both of the electromagnetic waves to be used for the data communication and the electromagnetic waves to be used for the power transmission with a frequency different from the frequency of said electromagnetic waves to be used for the data communication.

29. The data communication apparatus according to claim 28, wherein

said data communication apparatus is a data communication apparatus capable of sending, to said another data communication apparatus, both of the electromagnetic waves to be used for the data communication and having a variable frequency and the electromagnetic waves to be used for the power transmission and having a fixed frequency that is different from the frequency of said electromagnetic waves to be used for the data communication, and

said conversion method designating means designates said conversion method to be executed corresponding to the frequency of the electromagnetic waves to be used for the data communication.

30. The data communication apparatus according to claim 28, wherein said electromagnetic waves to be used for the data communication and for the power transmission include at least one of the electromagnetic waves used for the data communication and the electromagnetic waves used for the power transmission having a variable frequency, and said conversion method designating means includes frequency determination means for determining the frequency of the electromagnetic waves having said variable frequency according to a prescribed determination system, and selects said conversion method to be executed corresponding to the variable frequency of the electromagnetic waves determined by the frequency determination means.

31. The data communication apparatus according to claim 30, wherein

said data communication means includes

a resonance circuit having an antenna for performing data communication or power transmission utilizing electromagnetic waves and having a resonance frequency that can be switched by switching means, and

a variable oscillating circuit that is an oscillating circuit of a variable frequency for giving electrical oscillation to the resonance circuit by performing oscillation of the frequency determined by said frequency determination means, and

said conversion method designating means includes resonance frequency setting means that uses said switching means to set the resonance frequency of the resonance circuit to a favorable resonance frequency that corresponds to the frequency of the electromagnetic waves determined by said frequency determination means.

32. The data communication apparatus according to claim 30, wherein said frequency determination means is characterized by determining said variable frequency of the electromagnetic waves at random.

33. The data communication apparatus according to claim 1, wherein

said data communication apparatus is either one of an interrogator or a responsor of an IC card communication system, and

said another data communication apparatus is the other one of the interrogator or the responsor of the IC card communication system.

34. The data communication apparatus according to claim 1, wherein said data converting means prepares as the conversion method for conversion between the original data and the processed data, at least two conversion methods including the following systems to be used independently or as a combination thereof:

(a1) a dummy data inserting system in which dummy data are inserted between the original data to obtain the processed data,

(a2) a bit inverting system in which a prescribed bit of the original data is inverted to obtain the processed data, and

(a3) a data dividing system in which the original data are divided to obtain the process data.

35. A data communication system performing communication of processed data between a data communication apparatus and another data communication apparatus, wherein

said data communication apparatus includes

first data communication means for performing communication of the processed data with said another data communication apparatus,

first conversion method designating means for selecting and designating one of a plurality of conversion methods for conversion of the original data and the processed data as a conversion method to be executed, corresponding to a prescribed condition that may be altered and can be commonly recognized with said another data communication apparatus, and

first data converting means for converting the processed data obtained from the data communication means to the original data or converting the original data to the processed data for application to said first data communication means, according to the conversion method designated by said first conversion method designating means, and

said another data communication apparatus includes

second data communication means for performing communication of the processed data with said data communication apparatus,

second conversion method designating means for selecting and designating one of a plurality of conversion methods for conversion of the original data and the processed data as a conversion method to be executed, corresponding to said prescribed condition, and

second data converting means for converting the processed data obtained from said second data communication means to the original data or converting the original data to the processed data for application to said second data communication means, according to the conversion method designated by said second conversion method designating means,

the conversion method designated in said data communication apparatus and the conversion method designated in said another data communication apparatus being made same.

36. A data communication method for performing communication of processed data between at least two data communication apparatuses, comprising the steps of:

selecting and designating one of a plurality of conversion methods for conversion of original data and the processed data as a conversion method to be executed, corresponding to a prescribed condition that may be altered and can be commonly recognized between respective data communication apparatuses;

converting the processed data obtained from another data communication apparatus to the original data or converting the original data to the processed data for application to the another data communication apparatus, according to the designated conversion method; and

allocating a same conversion method as the conversion method designated for each data communication apparatus.