Transponder detector for an RFID system generating a progression of detection signals
First Claim
1. A transponder detector comprising:
- an antenna assembly;
a first circuit coupled to said antenna assembly, said first circuit configured to generate and transmit a first detection signal at a first frequency and a second detection signal at a second frequency via said antenna assembly;
a second circuit coupled to said antenna assembly, said second circuit configured to receive response signals from said antenna assembly resulting from transmission of said first and second detection signals, wherein said response signals have a transponder detection parameter; and
a controller operable to switch the detector between a detection mode and a data transaction mode, the controller further configured to detect the presence of a transponder having a transponder frequency in a proximal space of said transponder detector based on said detection parameter and upon such detection to switch the detector into the data transaction mode;
wherein said first circuit comprises a series resistance having a first switched series resistor, a first resistance switch, a second switched series resistor, and a second resistance switch, and further comprises a parallel capacitance having a first switched parallel capacitor, a first capacitance switch, a second switched parallel capacitor, and a second capacitance switch, wherein the series resistance and parallel capacitance are connected by an inverter, and wherein said first and second detection signals are generated by cooperatively controlling positions of said first and second resistance and capacitance switches.
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Accused Products
Abstract
A transponder detector is provided with capabilities for detecting the presence and type of a transponder in its read range while operating at low power. The transponder detector includes an antenna assembly and a detection signal generator circuit coupled to the antenna assembly. The detection signal generator circuit is capable of generating a progression of detection signals on the antenna assembly across a range of frequencies. The transponder detector further includes a response signal receiver circuit coupled to the antenna assembly to receive a progression of response signals from the antenna assembly resulting from the progression of detection signals. A controller is coupled to the response signal receiver circuit which determines the presence and type of the transponder based on an evaluation of a transponder detection parameter in the progression of response signals.
34 Citations
24 Claims
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1. A transponder detector comprising:
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an antenna assembly; a first circuit coupled to said antenna assembly, said first circuit configured to generate and transmit a first detection signal at a first frequency and a second detection signal at a second frequency via said antenna assembly; a second circuit coupled to said antenna assembly, said second circuit configured to receive response signals from said antenna assembly resulting from transmission of said first and second detection signals, wherein said response signals have a transponder detection parameter; and a controller operable to switch the detector between a detection mode and a data transaction mode, the controller further configured to detect the presence of a transponder having a transponder frequency in a proximal space of said transponder detector based on said detection parameter and upon such detection to switch the detector into the data transaction mode; wherein said first circuit comprises a series resistance having a first switched series resistor, a first resistance switch, a second switched series resistor, and a second resistance switch, and further comprises a parallel capacitance having a first switched parallel capacitor, a first capacitance switch, a second switched parallel capacitor, and a second capacitance switch, wherein the series resistance and parallel capacitance are connected by an inverter, and wherein said first and second detection signals are generated by cooperatively controlling positions of said first and second resistance and capacitance switches. - View Dependent Claims (2, 3, 4, 5)
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6. A transponder detector comprising:
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an antenna assembly; a first circuit coupled to said antenna assembly, said first circuit configured to generate and transmit a first detection signal at a first frequency and a second detection signal at a second frequency via said antenna assembly; and a second circuit coupled to said antenna assembly, said second circuit configured to receive response signals from said antenna assembly resulting from transmission of said first and second detection signals, wherein said response signals have a transponder detection parameter, wherein said first circuit comprises a series resistance having a first switched series resistor, a first resistance switch, a second switched series resistor, and a second resistance switch, and further comprises a parallel capacitance having a first switched parallel capacitor, a first capacitance switch, a second switched parallel capacitor, and a second capacitance switch, wherein an inverter is connected between the series resistance and parallel capacitance, and wherein said first and second detection signals are generated by cooperatively controlling positions of said first and second resistance and capacitance switches.
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7. A transponder detector comprising:
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an antenna assembly; a first circuit coupled to said antenna assembly, said first circuit configured to generate and transmit a first detection signal at a first frequency and a second detection signal at a second frequency via said antenna assembly; and a second circuit coupled to said antenna assembly, said second circuit configured to receive response signals from said antenna assembly resulting from transmission of said first and second detection signals, wherein said response signals have a transponder detection parameter, wherein said first circuit comprises a series resistance having a switched series resistor and a resistance switch and a parallel capacitance having a switched parallel capacitor and a capacitance switch, said series resistance and parallel capacitance connected between a ping output signal source and said antenna assembly such that frequency of said detection signals is changeable by cooperatively controlling positions of said resistance and capacitance switches, wherein an inverter is connected between the series resistance and the parallel capacitance. - View Dependent Claims (8, 9, 10)
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11. A transponder detector comprising:
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an antenna assembly; a first circuit coupled to said antenna assembly and configured to generate and transmit a detection signal progression including a high frequency detection signal at a high frequency, a middle frequency detection signal at a middle frequency and a low frequency detection signal a low frequency via said antenna assembly, wherein said first circuit comprises a series resistance having a first switched series resistor, a first resistance switch, and a second switched series resistor and a second resistance switch, and said first circuit further comprises a parallel capacitance connected to the series resistance via an inverter and the parallel capacitance having a first switched parallel capacitor, a first capacitance switch, a second switched parallel capacitor and a second capacitance switch, further wherein said detection signal progression is generated by cooperatively controlling positions of said first and second resistance and capacitance switches; and a second circuit coupled to said antenna assembly, said second circuit configured to receive a progression of response signals from said antenna assembly, said response signals having a transponder detection parameter. - View Dependent Claims (12, 13, 14)
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15. A frequency ranging method for transponder detection comprising:
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transmitting a first detection signal at a first frequency and a second detection signal at a second frequency via a first circuit coupled to an antenna coil in an antenna assembly, wherein said first circuit comprises a series resistance having a first switched series resistor, a first resistance switch, a second switched series resistor, and a second resistance switch, and further comprises a parallel capacitance having a first switched parallel capacitor, a first capacitance switch, a second switched parallel capacitor, and a second capacitance switch, wherein the series resistance and capacitance are connected via an inverter, and wherein said first and second detection signals are generated by cooperatively controlling positions of said first and second resistance and capacitance switches; receiving a plurality of response signals from said antenna assembly resulting from transmission of said first and second detection signals, wherein said response signals have a transponder detection parameter; detecting a transponder having a transponder frequency in a proximal space of said antenna assembly based on a change in value of said transponder detection parameter for said response signals. - View Dependent Claims (16, 17, 18)
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19. A frequency ranging method for transponder detection comprising:
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transmitting a progression of detection signals via a first circuit coupled to an antenna assembly, said progression of detection signals including a high frequency detection signal at a high frequency, a middle frequency detection signal at a middle frequency and a low frequency detection signal a low frequency, wherein said first circuit comprises a series resistance having a first switched series resistor, a first resistance switch, a second switched series resistor, and a second resistance switch, and further comprises a parallel capacitance having a first switched parallel capacitor, a first capacitance switch, a second switched parallel capacitor, and a second capacitance switch, wherein an inverter is connected between the series resistance and parallel capacitance, and wherein said progression of detection signals are generated by cooperatively controlling positions of said first and second resistance and capacitance switches; receiving a progression of response signals from said antenna assembly resulting from transmission of said progression of detection signals, wherein said response signals have a transponder detection parameter; detecting a transponder having a transponder frequency in a proximal space of said antenna assembly based on a change in value of said transponder detection parameter for said progression of response signals.
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20. A reader for an RFID system comprising:
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a reader antenna assembly; an excitation signal generator circuit coupled to said reader antenna assembly; a transponder signal receiver circuit coupled to said reader antenna assembly; a main controller coupled to said excitation signal generator circuit and said transponder signal receiver circuit; and a detection signal generator circuit coupled to said reader antenna assembly and configured to generate and transmit a detection signal progression including a high frequency detection signal at a high frequency, a middle frequency detection signal at a middle frequency and a low frequency detection signal a low frequency via said antenna assembly, wherein said detection signal generator circuit comprises a series resistance having a first switched series resistor, a first resistance switch, and a second switched series resistor and a second resistance switch, and said detection signal generator circuit further comprises a parallel capacitance having a first switched parallel capacitor, a first capacitance switch, a second switched parallel capacitor and a second capacitance switch, wherein the second parallel capacitor is connected between an inverter and the parallel capacitance, further wherein said detection signal progression is generated by cooperatively controlling positions of said first and second resistance and capacitance switches; a response signal receiver circuit coupled to said reader antenna assembly, said response signal receiver circuit configured to receive a progression of response signals from said antenna assembly, said response signals having a transponder detection parameter; and a wakeup controller coupled to said detection signal generator circuit and said response signal receiver circuit, said wakeup controller configured to evaluate a change in value of said transponder detection parameter to detect a transponder in a read range of said reader. - View Dependent Claims (21, 22, 23, 24)
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Specification