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US 5,291,205 AGranted
Radio frequency automatic identification system
AssigneeGordian Holding Corporation
InventorMorton Greene
Life of this patent
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AssigneeGordian Holding Corporation
InventorMorton Greene
Estimating the term…
A radio frequency automatic identification system detects targets which include solid resonators resonating at several frequencies, attributing information to the frequencies at which the target resonates. Preferred resonators are quartz crystals, which may be made by a process of heating quartz to soften it and cutting crystals to approximate size and resonant frequency. Resonators produced by such a process are measured to determine their actual resonant frequency, and preferably the crystals are sorted into predetermined frequency windows in accordance with their measured resonant frequency. A set of resonators having frequencies corresponding to predetermined data is selected from the sorted groups of resonators and incorporated into a target. The preferred target is an ink-like material having a plurality of resonators disposed in a matrix which is radio frequency transparent at the frequency of interest. Targets are preferably detected by repetitively sweeping the frequency of the interrogating signal through a range which includes the information-bearing range of the system.
Apparatus for detecting or identifying radio frequency responsive targets in a target field, said targets being resonant at a plurality of radio frequencies and producing response signals at the frequencies at which they are resonant in response to radio frequency interrogating signals, comprising a transmitter for transmitting radio frequency interrogating signals to a target field and a receiver for receiving radio frequency response signals from said target field, said transmitter transmitting a periodic interrogating signal which during each period continuously varies in frequency over a target frequency range in a predetermined manner, and said receiver continuously receiving radio frequency signals form the target field during each period and producing an output attributing predetermined information to response signals from the target field in accordance with the times during each period at which changes in the response signal occur.
A method of detection, in a target field, of information-bearing radio frequency responsive targets which respond at a plurality of frequencies within a target frequency range, comprising the steps of:
A method of detection, within a target field, of radio frequency responsive targets which resonate at a plurality of frequencies within a target frequency range to provide radio frequency detectable information comprising the steps of:
Dependencies are inferred from the claim text.