| Autor: |
Sackman, G. L., Barta, A. F., Well, G. C., Robinson, K. G. |
| Zdroj: |
Journal of the Acoustical Society of America; 1967, Vol. 42 Issue 5, p1186-1186, 1p |
| Abstrakt: |
An underwater object is insonified by a 455-kHz pulse from a separate projector, and the reflected waves are focused onto a 9×9-element mosaic transducer fabricated from a single ceramic block, located at the focal plane of 90-cm-diam parabolic reflector. The transducer voltages are amplified by a set of 81 identical amplifiers with range gates, then rectified to charge storage capacitors. The capacitors are scanned in sequence by solid state switches driven by a microcircuit logic network, which also generates sweep voltages for the intensity modulated display. Resolution of 12° and tangential sensitivity of -110 dB re 1 W/cm2 have been measured, with interchannel crosstalk on the order of -20 dB. Digital-computer simulation of the system has emphasized the importance of aperture shading and proper reconstruction of the sampled image, in improving image quality. [This work was supported in part by the Office of Naval Research.] [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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