Signal processing system for flow velocity in laser doppler velocimeter
US5005144A · kind A · utility
Inventors
Key dates
| Filing date | Jul 10, 1989 |
| Grant date | Apr 2, 1991 |
| Priority date | — |
| Expiry date | Jul 10, 2009 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01P5/26
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A period of a correlation signal from a laser Doppler velocimeter is calculated from crossing points at which a correlation function crosses over a threshold level by clipping and digitizing a Doppler burst signal, thereby enabling an accurate and real time measurement to be made of a flow velocity, even in low SNR Doppler signals. Smoothing the waveform of a correlation signal further improves measurement accuracy. When the threshold level is set to be the 1/2 value of the autocorrelation function at .tau.=0, a crossing point is precisely detected even in an uneven correlation function or small amplitude of the crosscorrelation function, thus further increasing measurement accuracy.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.