Constant frequency pulsed phase-locked loop measuring device
US5214955A · kind A · utility
30Cited by
9References
7Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Aug 26, 1991 |
| Grant date | Jun 1, 1993 |
| Priority date | — |
| Expiry date | Aug 26, 2011 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2291/02872
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A measuring apparatus uses a fixed frequency oscillator to measure small changes in the phase velocity ultrasonic sound when a sample is exposed to environmental changes such as changes in pressure, temperature, etc. The invention automatically balances electrical phase shifts against the acoustical phase shifts in order to obtain an accurate measurement of electrical phase shifts.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.