Measuring device for measuring relative speed

摘要

With a measuring device which is arranged inside a body (1), the relative speed with respect to a medium (L) is measured. Said measuring device contains an acoustic transmitter (2), an acoustic receiver (6) and an evaluation device (7). A first part (S1) of the sound wave which is output by the transmitter propagates directly to the receiver; a second part (S2) propagates via the medium. The relative speed is determined from the difference between the frequencies of the two partial waves. <IMAGE>