V.G.Basovsky, I.V.Vovk, A.G.Leiko On some specific errors occurring when evaluating sound reflection coefficient in a hydroacoustic tube by a two-hydrophone technique |
Acoustic bulletin, Vol. 8 ¹ 1-2, (2005) |
| A hydroacoustic tube designed for measuring a coefficient of sound reflection from various materials and constructions by a two-hydrophone technique is examined. It is shown that the specific, unstudied before, vibrational interferences essentially affecting the measurement accuracy may arise in such devices. It is ascertained that the reason of their occurrence is a mechanical contact between the sound source and the walls of the tube through its structure elements. On the basis of offered calculation scheme the relative noise level and coefficient of sound reflection from thin air layer were numerically estimated. It is shown that for some frequencies the determining of reflection coefficient might become practically impossible. The two ways of noise level reduction are proposed. One of them consists in rational choice of tube structure elements, while the second one is based on special processing of the signal received from vibrosensors and hydrophones placed inside the tube. |
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KEY WORDS: a hydroacoustic tube, two-hydrophone technique, vibrosensor |
| TEXT LANGUAGE: Russian |