Contactless data processing apparatus

• US 5,354,975 A
• Filed: 06/03/1993
• Issued: 10/11/1994
• Est. Priority Date: 07/01/1992
• Status: Expired due to Fees

• Current Assignee: Tokyo Keiki Inc.
• Original Assignee: Tokyo Keiki Inc.
• Inventors: Hayakawa, Shin-ichi, Ishibashi, Yoshihito, Matsumoto, Masakatsu
• Primary Examiner(s): Hajec, Donald
• Assistant Examiner(s): FILIPEK, JEFFER
• Application Number:
  US08/070,789
• Time in Patent Office: 495 Days
• Field of Search: 235/380, 235/449, 235/382, 380/23, 380/24, 380/49, 380/2, 375/1, 371/57.1, 340/825.5
• US Class Current: 235/380
• CPC Class Codes: G06K 7/0008 General problems related to the reading of electronic memory record carriers, independent of its reading method, e.g. power transfer
• CPC Class Codes: G06Q 20/367 involving electronic purses or money safes
• CPC Class Codes: G07B 15/02 taking into account a variable factor such as distance or time, e.g. for passenger transport, parking systems or car rental systems G07B15/06 takes precedence; taximeters G07B13/00; parking meters per se G07F17/24; car rental systems per se G07B15/00

Abstract

When a control section of a data carrier discriminates a command from a reader/writer, either one of two kinds of pseudo random signals is returned in accordance with a bit 0 or 1 of response data. When two autocorrelation values obtained by correlation arithmetic operations are simultaneously equal to or greater than a predetermined threshold value, the reader/writer determines that a communication has been executed with two or more data carriers, so that an error warning, an access stop, a retry, or the like is executed. The reader/writer compares the autocorrelation peak value obtained from the pseudo random signal from the data carrier with a threshold value. When it is equal to or greater than the threshold value, the reading operation is executed. In the reading operation of continuous data bits from the data carrier, the reader/writer selects the minimum value from among the autocorrelation peak values of the bits obtained by the correlation arithmetic operations and stores the selected minimum value. When the minimum memory value is smaller than a threshold value, it is determined that data could not correctly be read, so that an error is indicated.

Claims

1. A contactless data processing apparatus comprising:

a portable data carrier means for receiving a contactless coupling from an outside source and for executing at least a reading operation of data from said outside source to a built-in memory means; and

a data processing means for executing at least the reading operation of data from said outside source to said data carrier means by the contactless coupling;

wherein said data carrier means has a response means for returning one of two kinds of pseudo random signals which have been predetermined in correspondence to a bit 0 or 1 of response data when a predetermined command is received from said data processing means; and

said data processing means has;

a correlation operating means for holding the same signals as said two kinds of pseudo random signals of said data carrier means and for obtaining autocorrelations with a received signal; and

a judging means for determining that two or more data carrier means have been simultaneously accessed by an outside source when the autocorrelation values of said two kinds of pseudo random signals which have been obtained by said correlation operating means are simultaneously equal to or greater than a predetermined threshold value.

2. An apparatus according to claim 1, wherein when said judging means of said data processing means has determined that two or more data carrier means have been simultaneously accessed, an access inhibiting command to inhibit the subsequent access is generated and inputted to said data carrier means.

3. An apparatus according to claim 2, wherein said data carrier means has access suppressing means for making it impossible access to all of the memory areas when said access inhibiting command is received.

4. An apparatus according to claim 2, wherein said data carrier means has access suppressing means for making it impossible access to a part of the memory areas when said access inhibiting command is received.

5. An apparatus according to claim 1, wherein the occurrence of an error is indicated when said judging means of said data processing means determines that two or more data carrier means have been simultaneously accessed.

6. An apparatus according to claim 1, wherein when said judging means of said data processing means have been determines that two or more data carrier means simultaneously accessed, the access is stopped at a time point when said determination has been made.

7. An apparatus according to claim 1, wherein when said judging means of said data processing means have been determines that two or more data carrier means simultaneously accessed, said access is retried.

8. An apparatus according to claim 1, wherein said data carrier means has a power supply means for generating an operating electric power from a transmission signal of said data processing means, and when said judging means determines that two or more data carrier means have been simultaneously accessed, said data processing means stops the transmission to the data carrier means, thereby shutting off the electric power supply.

9. An apparatus according to claim 1, wherein said data processing means has a write access means for writing data into said data carrier means, and in the case when said judging means of said data processing means determines that two or more data carrier means have been simultaneously accessed, the write access to the data carrier means is inhibited.

10. A contactless data processing apparatus comprising:

a portable data carrier means for receiving a contactless coupling from an outside source and for executing at lest a reading operation of data from said outside source to a built-in memory means; and

a data processing means for executing at least the reading operation of data from said outside source to said data carrier means by the contactless coupling;

and wherein said data carrier means has a response means for returning a predetermined pseudo random signal when a predetermined command is received from a reader/writer means; and

said data processing means has;

a correlation operating means for obtaining an autocorrelation between the same signal as said pseudo random signal of said data carrier means and a received signal; and

a read control means for executing the reading operation when an autocorrelation peak value obtained by said correlation operating means at a time point when the received signal coincides with a reference signal is equal to or greater than a predetermined threshold value;

wherein said read control means of said data processing means has a first threshold value TH₁ and a second threshold value TH₂ which is smaller than said first threshold value, and when the autocorrelation peak value obtained by said correlation operation means is equal to or greater than said first threshold value TH₂, the reading operation is executed, and when the autocorrelation peak value is smaller than the first threshold value TH₁ and is equal to or greater than said second threshold value TH₂, a comparing process for comparing the received signal of the pseudo random signal returned from the data carrier means and the autocorrelation peak value is repeated by a generation of a command, and when the autocorrelation peak value is smaller than the second threshold value TH₂, the reading operation is stopped.

11. A contactless data processing apparatus comprising:

a portable data carrier means for receiving a contactless coupling from an outside source and for executing at lest a reading operation of data from said outside source to a built-in memory means; and

a data processing means for executing at least the reading operation of data from said outside source to said data carrier means by the contactless coupling;

and wherein said data carrier means has a response means for returning a predetermined pseudo random signal when a predetermined command is received from a reader/writer means; and

said data processing means has;

a correlation operating means for obtaining an autocorrelation between the same signal as said pseudo random signal of said data carrier means and a received signal; and

a read control means for executing the reading operation when an autocorrelation peak value obtained by said correlation operating means at a time point when the received signal coincides with a reference signal is equal to or greater than a predetermined threshold value;

wherein said read control means of said data processing means obtains a differential coefficient indicative of an aging change between the preceding and present autocorrelation peak values, and when said differential coefficient is positive, it is determined that there is a tendency such that the autocorrelation peak value is increasing, and the comparing process to compare the autocorrelation peak value with the predetermined threshold value TH is repeated and, when the autocorrelation peak value is equal to or greater than the threshold value TH, the reading operation is executed, and further when the differential coefficient is negative, it is determined that there is a tendency such that the autocorrelation peak value is decreasing, and the reading operation is stopped.

12. A contactless data processing apparatus comprising:

a portable data carrier means for receiving a contactless coupling from an outside source and for executing at least a reading operation of data from said outside source to a built-in memory means; and

a data processing means for executing at least the reading operation of data from said outside source to said data carrier means by a contactless coupling;

wherein said data carrier means has a response means for receiving and decoding a command from said data processing means and for returning arbitrary response data as a predetermined pseudo random signal corresponding to a bit; and

said data processing means has;

a correlation operating means for obtaining an autocorrelation between the same reference signal as said pseudo random signal of said data carrier means and a received signal;

a minimum value selecting means for selecting a minimum value among the autocorrelation peak values of every bit obtained by said correlation operating means and for storing said minimum value in a memory, and

a comparing means for generating a signal indicative of a read error when said minimum memory value in said memory is smaller than a predetermined threshold value.

13. An apparatus according to claim 12, wherein said comparing means of said data processing means displays a message for allowing the data carrier means to approach a position at a distance where said data processing means can communicate by the generation of said read error signal.