ASA 129th Meeting - Washington, DC - 1995 May 30 .. Jun 06

1aAO3. Signal generation and processing for the R/P Flip ATOC transmissions.

Kurt Metzger

Ted Birdsall

CSPL, Univ. of Michigan, Ann Arbor, MI 48109-2122

The waveforms transmitted during the November 1994 Acoustic Thermometry of Ocean Climate (ATOC) project R/P Flip measurement used an m-sequence phase modulated 75-Hz carrier, two carrier cycles per digit. Because the source had an inherent Q of 5, the drive waveform was modified in order to produce a two cycle per digit output. This paper describes the basic characteristics of the source, the procedure used to broaden the source bandwidth, the enforcement of a source peak power limit, and shows the resulting waveforms. The received waveforms possessed small amounts of Doppler ``shift'' caused by the motion of Flip on its mooring. Doppler limits the amount of time over which receptions can be integrated. Doppler normally must be treated as time compression/expansion. However, if the Doppler is sufficiently small it can be treated as simple time shift. This paper compares the results of using both approaches to account for the motion of Flip. [Work supported by the Strategic Environmental Research and Development Program through ARPA.]