Patent ID: 9683954
Date: 2017-06-20
CPC Classifications: G01N

Claim:
1. A material signature detector for non-contact assessment of changes in critical material properties comprising: an electrical circuit comprising a sense resistor in series with both an element and a sample under test; a frequency source electrically coupled between the sense resistor and a ground return; a quadrature demodulator electrically coupled to the sense resistor; and an analog to digital converter to create digital signatures from analog signals received from the quadrature demodulator; a computer having a processor, memory, and access to computer readable media; the computer configured to receive the created digital signatures; a computer program stored on the computer readable media where the computer program executes the steps of: applying a signal between the sense resistor and a ground return; demodulating the signal across the sense resistor using a quadrature demodulator; receiving the demodulated analog signal from the quadrature demodulator with an analog to digital converter; converting with the analog to digital converter the demodulated analog signal to a digital signature that is indicative of material properties of the sample under test; changing the impedance value of the element; applying a signal between the sense resistor and a ground return; demodulating the signal across the sense resistor using a quadrature demodulator; receiving the demodulated analog signal from the quadrature demodulator with an analog to digital converter; converting with the analog to digital converter the demodulated analog signal to another digital signature that is further indicative of material properties of the sample under test.