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Identification transponder circuit

  • US 5,028,918 A
  • Filed: 12/18/1989
  • Issued: 07/02/1991
  • Est. Priority Date: 12/18/1989
  • Status: Expired due to Fees
First Claim
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1. A state variable phase encoded transponder circuit for use in a device for the transmission of identification and other data from the device to an interrogating unit comprisinga memory portion containing stored data including an identification code and three data word enable flags and an external data enable flag;

  • a data bus connected to carry data from the memory portion;

    timing circuitry connected to address the memory portion to access stored data including the identification code therein and to cause it to be transferred from the memory in a series of words in parallel on the data bus;

    parallel to serial data conversion means connected to the data bus to convert data thereon into a serial phase encoded data stream;

    three data enable latches connected to the data bus to test for the external data word enable flags;

    a parallel input external data bus connected so as to be capable of providing external data to the data bus;

    gating means connected for operating the external data bus only when the data enable latch has been activated by the external data enable flag, the gating means being further connected to the timing means to enable the external data bus only during times which do not conflict with the transmission of the identification code from the memory so that the identification code and parallel input data may be converted by the parallel to serial conversion means into a common serial data stream; and

    wherein the message transmitted by the circuit is up to eight words in length, and wherein the other data to be transmitted is any combination of the fifth, sixth and seventh words of the message.

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