Dual mode transmitter-receiver and decoder for RF transponder tags
First Claim
1. An RFID reader, comprising:
- a transmitter configured to transmit RF signals to a plurality of RFID tags configured to modulate the RF signals according to first and second modulation schemes;
a receiver including a demodulator configured to demodulate RF signals received from said plurality of RFID tags that are modulated according to the first and second modulation schemes; and
a decoder configured to decode received signals that are encoded according to different encoding schemes.
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Abstract
An enhanced backscatter RF-ID tag reader system and multiprotocol RF tag reader system is provided. In a multiprotocol mode, the system emits a non-stationary interrogation signal, and decodes a phase modulated backscatter signal by detecting a stronger phase component from quadrature phase representations or determining phase transition edges in a phase of a received signal. The RF tag reader system predicts or follows the phase of the backscatter signal, thereby avoiding interference from nulls in the received signal waveform due to the non-stationary interrogation signal, relative movement or environmental effects. An acoustic RF-ID tag detection system detects the reradiated signal corresponding to respective transformation of a signal in the tag. Detection of either type of RF-ID tags therefore is possible, and the absence of any tag or absence of any valid tag also determined.
56 Citations
18 Claims
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1. An RFID reader, comprising:
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a transmitter configured to transmit RF signals to a plurality of RFID tags configured to modulate the RF signals according to first and second modulation schemes; a receiver including a demodulator configured to demodulate RF signals received from said plurality of RFID tags that are modulated according to the first and second modulation schemes; and a decoder configured to decode received signals that are encoded according to different encoding schemes. - View Dependent Claims (2, 3, 4, 5, 6)
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7. An RFID reader, comprising:
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a transmitter configured to transmit RF signals to a plurality of RFID tags; a receiver including a demodulator configured to demodulate RF signals received from the plurality of RFID tags; and a decoder configured to decode received signals that are encoded according to different encoding schemes. - View Dependent Claims (8, 9, 10, 11, 12, 13)
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14. An RFID reader, comprising:
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a transmitter configured to transmit RF signals to a first backscatter modulation tag configured to backscatter modulate RF signals according to a first modulation scheme and to a second backscatter modulation tag configured to backscatter modulate RF signals according to a second backscatter modulation scheme; and a receiver including a demodulator configured to demodulate RF signals backscattered from the first backscatter modulation tag and demodulate RF signals backscattered from the second backscatter modulation tag. - View Dependent Claims (15, 16, 17, 18)
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Specification