| 摘要 |
System for the remote measurement of the relative speeds within a moving fluid, in particular water and air and comprising: - an emission of acoustic wavetrains along at least one specified direction - a reception of the waves diffused in particular by the turbulence remote from the emission - a measurement of the frequency of the waves received - a determination of the frequency deviation, equal to the difference of the emitted and received frequencies - an evaluation of the velocity component of the fluid by the DOPPLER formula. The determination of the value of the real Doppler component is undertaken by a global frequency measurement in a so-called "working" pass band substantially centred on the emission frequency and by a simultaneous estimate of the ratio between the powers of the background noise and of the useful signal which are sensed; this permits this global measurement to be corrected. <IMAGE> |
