Spread spectrum frequency hopping reader system
AssigneeAmtech Corporation
InventorsWesley M. Mays, Aaron J. Kam Siu, Mike D. Fontanarosa
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Abstract
An apparatus for sourcing an interrogation signal for use in a object identification system including a frequency hopping source for generation of an interrogation signal which is coupled to a homo dyne radio for transmission by a bi-directional antenna to a tag. Upon receipt, the tag provides a return signal that is backscatter modulated to include tag identification or other data which is processed by the sourcing system. The frequency hopping source includes a voltage controller oscillator which is driven by a pseudo random code generator for selecting one of a plurality of hopping frequencies at which the interrogation signal is to be generated based on the available bandwidth.
Claims20
A reader for use in an interrogation system, the reader generating a radio frequency signal to be returned by an electronic tag when the tag enters a predefined envelope region associated with the reader, the reader comprising:
- a radio frequency source outputting a radio frequency signal at one of a plurality of frequencies within a frequency range;
- means for hopping the radio frequency signal according to a first sequence among the plurality of frequencies in the frequency range;
- a detector for detecting destructive interference in a return signal from an electronic tag located within an envelope region associated with the reader;
- and
- a controller operating to vary the hopping upon the detection of destructive interference in the return signal.
A reader for reading data from an electronic tag comprising:
- a bi-directional antenna;
- a frequency hopping source for generating an interrogation signal at a frequency within a frequency range according to a first sequence;
- a homodyne radio for transmitting the interrogation signal to the electronic tag through the antenna and for receiving a radio frequency signal returned from the electronic tag;
- means for processing the radio frequency signal to decode the data from the electronic tag;
- and
- a controller operating to vary the hopping of the frequency hopping source to minimize occurrences of interference among adjacent readers.
Dependencies are inferred from the claim text.