Dual mode transmitter-receiver and decoder for RF transponder tags
First Claim
1. A dual mode tag identification system, comprising a radio frequency interrogation signal source, a radio frequency receiver and an analyzer, in which a reradiated modified representation of an interrogation signal from the interrogation signal source is analyzed to determine a data transmission mode, being responsive to respective first and second modes having respectively different formats of a time sequence of characteristic identifying modulation states imposed on said interrogation signal.
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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-DD tags therefore is possible, and the absence of any tag or absence of any valid tag also determined.
135 Citations
24 Claims
- 1. A dual mode tag identification system, comprising a radio frequency interrogation signal source, a radio frequency receiver and an analyzer, in which a reradiated modified representation of an interrogation signal from the interrogation signal source is analyzed to determine a data transmission mode, being responsive to respective first and second modes having respectively different formats of a time sequence of characteristic identifying modulation states imposed on said interrogation signal.
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24. A dual mode tag identification system, comprising a radio frequency interrogation signal source, a radio frequency receiver and first and second analyzers, in which a reradiated modified representation of an interrogation signal from the interrogation signal source is analyzed to determine a data transmission mode, being responsive to respective first and second modes, each having a distinct structure of identifying modulation states, having distinct time-domain characteristics corresponding to modulation states imposed on said interrogation signal, modulation states of said first mode being analyzed by a first analyzer and modulation states of said second mode being analyzed by a second analyzer.
Specification