| 摘要 |
<p>The testing procedure involves using at least one independent acoustic transducer (12) which is of a non-directional type, and receiving the same signal simultaneously on this transducer and on the aerial (10). Comparison is made between the signals for eventual identification of fixed echoes and verification of whether the aerial (10) and its cabling arrangement, relay system, amplification and signal processing system are or are not in a nominal operating state. The test signals may consist of a signal train, transmitted from the aerial itself (10), so that both the aerial and the test transducer can receive the retro-reflected signals. By use of several test transducers and comparison of their signals it is possible to deduce the direction and distance of the obstacles giving rise to fixed echoes.</p> |
