Long-Range Shallow-Water Propagation Loss Fluctuations,
NAVY ELECTRONICS LAB SAN DIEGO CALIF
Pagination or Media Count:
One of the most striking features of the long-range shallow-water propagation of sonic frequencies is the fluctuation of the received signals. When a steady single-frequency tone is transmitted, the received signal level will vary over a range as much as 50-db. The fluctuation characteristics of a typical record of received sound were studied to yield information about 1 the amplitude distribution functions, 2 the cross-correlations between signals received at different hydrophones, and 3 the autocorrelations and power spectra of the signal envelopes. The shallow water results presented are for an almost ideal flat 60-fathom sand bottom at ranges of 10, 15, 20, and 30 kyd for frequencies of 350, 700, 1200, and 2,400 cps and for a 50-fathom nondepositional miocene sandstone bottom at ranges of 4, 8, 16, and 25 kyds for frequencies of 700 and 1200 cps and, at ranges of 4 and 16 kyds for frequencies of 1200 and 2,400 cps.
- Acoustic Detection and Detectors