Multiple protocol transponder
First Claim
1. A multi-protocol transponder for communicating with a reader using RF communications in accordance with a plurality of possible protocols, the reader using a selected one of the plurality of possible protocols, the transponder comprising:
- an antenna;
an RF modem connected to the antenna for receiving an RF signal induced in the antenna by radiated RF energy from the reader, the RF modem demodulating the received RF signal and outputting a digital signal; and
a digital controller for receiving the digital signal and controlling the generation of a response signal in accordance with the selected protocol, the RF modem including a protocol detector for receiving the RF signal and identifying the selected one of the plurality of possible protocols based upon the radiant energy level of the received RF signal.
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Accused Products
Abstract
A multi protocol transponder for a communications network having a antenna for receiving a first RF signal transmitted according to a communications protocol and a detector for identifying the communications protocol from the first RF signal. A protocol controller is provided for executing the identified communications protocol to generate a second RF signal. Thereafter an antenna transmits the second RF signal according to the communications protocol either by active transmission or modulated backscatter. The transponder may implement a variety of wide area and localized lane based protocols for Automatic Vehicle Identification systems such as CVO and Toll systems.
74 Citations
16 Claims
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1. A multi-protocol transponder for communicating with a reader using RF communications in accordance with a plurality of possible protocols, the reader using a selected one of the plurality of possible protocols, the transponder comprising:
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an antenna;
an RF modem connected to the antenna for receiving an RF signal induced in the antenna by radiated RF energy from the reader, the RF modem demodulating the received RF signal and outputting a digital signal; and
a digital controller for receiving the digital signal and controlling the generation of a response signal in accordance with the selected protocol, the RF modem including a protocol detector for receiving the RF signal and identifying the selected one of the plurality of possible protocols based upon the radiant energy level of the received RF signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method for operating a multi-protocol transponder communicating with a reader using RF communications in accordance with a plurality of possible protocols, the reader using a selected one of the plurality of possible protocols, the transponder including an antenna, the method comprising the steps of:
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receiving an RF signal induced in the antenna by radiated RF energy from the reader;
identifying the selected one of the plurality of possible protocols based upon the radiant RF energy level of the received RF signal;
demodulating the received RF signal to obtain a digital signal; and
generating a response signal in accordance with the selected protocol. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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Specification