Electrical conductivity tester and methods thereof for accurately measuring time-varying and steady state conductivity using phase shift detection
First Claim
1. An electrical conductivity tester for accurately measuring the time-varying conductivity and steady-state conductivity of a test material, comprising:
- an oscillator means for generating a reference oscillator signal;
a single probe coil means for receiving said reference oscillator signal, for magnetically coupling to said test material, and for modifying said reference oscillator signal via electromagnetic induction to derive a modified transmission phase signal;
a phase detector means for deriving a transmission phase signal indicative of a phase difference by comparing said reference oscillator signal to said modified transmission phase signal, said transmission phase signal being convertible to said time varying conductivity; and
means for averaging said transmission phase signal over time and for generating an average phase signal, said average phase signal being convertible to steady-state conductivity of said test material.
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Accused Products
Abstract
An electrical conductivity tester accurately measures the time-varying electrical conductivity σ(t) and steady-state electrical conductivity σss of a test material. In a first embodiment, the transmission phase of a probe circuit is monitored to determine the conductivity of a test material. In the first embodiment, an oscillator circuit generates a reference oscillator signal. A probe circuit receives the reference oscillator signal, magnetically couples to the test material, and modifies the reference oscillator signal via electromagnetic induction to derive a modified transmission phase signal. Finally, a phase detector circuit derives a transmission phase signal by combining the reference oscillator signal and the modified transmission phase signal, the transmission phase signal being directly convertible to the conductivity. In a second embodiment, an amplifier is connected to the probe circuit to form an oscillator circuit. The oscillator circuit generates an oscillator signal in response to the magnetic coupling of the probe circuit with the test material. A frequency discriminator generates a frequency signal from the oscillator signal, the frequency signal being convertible to the conductivity.
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Citations
35 Claims
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1. An electrical conductivity tester for accurately measuring the time-varying conductivity and steady-state conductivity of a test material, comprising:
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an oscillator means for generating a reference oscillator signal; a single probe coil means for receiving said reference oscillator signal, for magnetically coupling to said test material, and for modifying said reference oscillator signal via electromagnetic induction to derive a modified transmission phase signal; a phase detector means for deriving a transmission phase signal indicative of a phase difference by comparing said reference oscillator signal to said modified transmission phase signal, said transmission phase signal being convertible to said time varying conductivity; and means for averaging said transmission phase signal over time and for generating an average phase signal, said average phase signal being convertible to steady-state conductivity of said test material. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 14)
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11. A method for accurately determining the time varying conductivity and steady-state conductivity of a test material, the method comprising the steps of:
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sending a reference oscillator signal to a single probe coil means; magnetically coupling said reference oscillator signal and said test material with said single probe coil means to derive a modified transmission phase signal; comparing said reference oscillator signal to said modified transmission phase signal to derive a transmission phase signal indicative of a phase difference, said transmission phase signal being convertible to said time-varying conductivity; and averaging said transmission phase signal to determine an average phase signal, said average phase signal being convertible to said steady-state conductivity of said test material. - View Dependent Claims (12, 13, 15)
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16. An electrical conductivity tester for accurately measuring the conductivity of a test material, comprising:
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an oscillator means for generating a reference oscillator signal; a probe means for receiving said reference oscillator signal, for magnetically coupling to said test material, and for modifying said reference oscillator signal via electromagnetic induction to derive a modified transmission phase signal; a phase detector means for deriving a transmission phase signal by comparing said reference oscillator signal to said modified transmission phase signal, said transmission phase signal being convertible to said conductivity; and a feedback means for filtering said transmission phase signal to derive an average transmission phase signal and for forwarding said average transmission phase signal to said phase detector means, said feedback means and said phase detector means for adjusting a phase of said reference oscillator signal so that said transmission phase signal is reduced to zero with a steady-state conductivity. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23, 24, 25)
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26. A method for accurately determining the conductivity of a test material, the method comprising the steps of:
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sending a reference oscillator signal to a probe circuit; magnetically coupling said reference oscillator signal and said test material to derive a modified transmission phase signal; comparing said reference oscillator signal to said modified transmission phase signal to derive a transmission phase signal, said transmission phase signal being convertible to said conductivity; filtering said transmission phase signal to derive an average transmission phase signal; and using said average transmission phase signal to adjust a phase of said reference oscillator signal so that said transmission phase signal is reduced to zero with a steady-state conductivity. - View Dependent Claims (27, 28, 29, 30, 31, 32, 33, 34, 35)
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Specification