Electronic recognition and identification system for identifying several master keys
First Claim
1. An electronic recognition and identification system for identifying one of a plurality of electrically coded passive objects each having at least one tuned electrical circuit which is resonant at at least one of a plurality of predetermined frequencies, comprising:
- signal source means for generating an alternating current signal, said alternating current signal having a frequency which varies with time over a range of frequencies including said plurality of predetermined frequencies;
a condition pulse generation network connected to said signal source means, said condition pulse generation network being responsive to said alternating current signal and operative to produce a condition pulse when one of the objects is proximate thereto and when the frequency of said alternating current signal passes through its predetermined frequency;
a plurality of reference pulse generating means each responsive to said alternating current signal and operative to produce a reference pulse when the frequency of said alternating current signal passes through a respective one of said plurality of predetermined frequencies;
means for selectively applying said alternating current signal to said plurality of reference pulse generating means; and
control signal generating means responsive to said condition pulses and said reference pulses and operative to produce a control signal when there is time coincidence between said condition pulse and one of said plurality of reference pulses thereby identifying the proximate object.
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Accused Products
Abstract
An electronic recognition and identification system for identifying one of a plurality of electrically coded keys, each having at least one tuned electrical circuit which is resonant at at least one of a plurality of predetermined frequencies. The system comprises a sweep oscillator for generating an alternating current signal. The alternating current signal has a frequency which varies with time over a range of frequencies including the plurality of predetermined frequencies. A condition pulse generating network is connected to the oscillator and produces a condition pulse when one of the keys is proximate thereto and when the frequency of the alternating current signal passes through its predetermined frequency. A plurality of reference pulse generating circuits are selectively connected to the oscillator by a sequential multiplexer. Each reference pulse generating circuit is responsive to the alternating current signal and is operative to produce a reference pulse when the frequency of the alternating current signal passes through one of the plurality of predetermined frequencies. A control circuit is responsive to the condition pulses and the reference pulses and is operative to produce a control signal when there is time coincidence between those pulses.
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Citations
8 Claims
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1. An electronic recognition and identification system for identifying one of a plurality of electrically coded passive objects each having at least one tuned electrical circuit which is resonant at at least one of a plurality of predetermined frequencies, comprising:
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signal source means for generating an alternating current signal, said alternating current signal having a frequency which varies with time over a range of frequencies including said plurality of predetermined frequencies; a condition pulse generation network connected to said signal source means, said condition pulse generation network being responsive to said alternating current signal and operative to produce a condition pulse when one of the objects is proximate thereto and when the frequency of said alternating current signal passes through its predetermined frequency; a plurality of reference pulse generating means each responsive to said alternating current signal and operative to produce a reference pulse when the frequency of said alternating current signal passes through a respective one of said plurality of predetermined frequencies; means for selectively applying said alternating current signal to said plurality of reference pulse generating means; and control signal generating means responsive to said condition pulses and said reference pulses and operative to produce a control signal when there is time coincidence between said condition pulse and one of said plurality of reference pulses thereby identifying the proximate object. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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Specification