Method and system for processing measurement signals to obtain a value for a physical parameter
US6092419A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 21, 1997 |
| Grant date | Jul 25, 2000 |
| Priority date | — |
| Expiry date | Nov 21, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2291/101
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
In a measurement system wherein time-varying physical signals containing frequency information related to a physical parameter of an object are measured to obtain corresponding time-varying measurement signals, a method and system are disclosed for processing the measurement signals to obtain a value for the physical parameter by first extracting the frequency information from the measurement signals. The frequency information includes at least one desired frequency and its amplitude and decay rate. Then, the frequency information is converted to a value for the physical parameter. The measurement signals are discrete time ultrasonic signals. Extraction is performed by transforming the ultrasonic signals to a Z-domain and converting at least one zero or pole in the Z-domain to the at least one frequency and its decay rate. The physical signals may be coherent light signals which are modulated based on the frequency information which is related to propagation of longitudinal ultrasonic waves in the object. When the object is a static film such as a cured layer formed on a substrate, the physical parameter may be thickness of the layer. When the object is a dynamic curable film such …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.