On the Performance of Underwater Data Transmission Systems Using Amplitude-Shift-Keying Techniques

As part of a general investigation into various aspects relating to underwater data transmission, an experimental amplitude- shift-keyed (ASK) system has been developed and tested. The system is described and the results from tests carried out with the system are presented. The tests, which were carried out under shallow-water transmission conditions, were designed to provide information relating to the limits of achievable performance. The results obtained indicate that with a simple system, it is possible, when using a peak transmitted power of only 50 mwatts, to transmit data at a rate of approximately 600 bits/sec over ranges up to 650 meters, and to do so with a probability of bit-error that is consistantly of the order of The results indicate that if the probability of bit-error is to be maintained at approximately le3, then significant improvements in system performance in the form of increases in range and data-rate should be possible provided greater transmitter power is used. However, in order to do so it would be necessary, in addition to using increased transmitter power, to employ a much more sophisticated system capable of overcoming the effects of pulse dispersion and multipath. 1. INTRODUCTIOS