Ultrasonic Doppler flow meter
US5111825A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 6, 1990 |
| Grant date | May 12, 1992 |
| Priority date | — |
| Expiry date | Nov 6, 2010 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01S15/584
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A flow meter for detecting a flow speed in such a manner that an ultrasonic pulsed continuous wave is repeatedly transmitted toward an object at predetermined intervals T, a phase vector indicative of the phase of a reception signal due to the reflected wave is produced at the predetermined intervals, the phase difference between the present phase vector and the preceding phase vector is detected, and a Doppler frequency is calculated from the average value of a plurality of phase difference values to obtain the speed of the object. The phase difference values are classified into a first group consisting of position phase difference values and a second group consisting of negative phase difference values, the cosine and sine values of the central angle of the positive phase difference values and the cosine and sine values of the central angle of the negative phase difference values are calculated, and the argument of a vector indicated by the weighted sum of cosine values and the weighted sum of sine values is calculated to be used as an average phase angle.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.