| 主权项 |
1. A method for determining physical and/or chemical properties of a medium on the basis of at least one first and one second acoustic wave, which each have at least partly propagated through the medium from at least one transmitter to at least one receiver, wherein
the acoustic waves each are generated by a transmit signal x0, x1. the first acoustic wave propagates through the medium along a first propagation direction and the second acoustic wave propagates through the medium along a second propagation direction different from the first propagation direction, and for a received first acoustic wave a first receive signal y0r, y1r is generated after its propagation through the medium along the first propagation direction and for a received second acoustic wave a second receive signal y0s, y1s is generated after its propagation through the medium along the second propagation direction, from the receive signals y0r, y1r; y0s, y1s a runtime difference Δt of the acoustic waves is determined and by means of a determined runtime difference Δt physical and/or chemical properties of the medium are determined, at least two different transmit signals x0, x1 of substantially the same fundamental frequency f are used, which have a specified phase offset to each other and by which a first and a second acoustic wave each are generated, so that for each propagation direction two receive signals y0r, y1r; y0s, y1s are generated, which originate from different transmit signals x0, x1 and a runtime difference Δt of the acoustic waves propagating along the two different propagation directions is determined by the four receive signals y0r, y1r; y0s, y1s. |
