The influence of the waveform of the transmitted signal on the signal to reverberation ratio of a moving sonar array is analysed on an experimental basis. Experiments were conducted during sea-trials in shallow water areas in September 98 and October 99. The aim of the trials was to compare the performance of three waveforms: frequency modulated (FM) signals, continuous wave (CW) signals and a train of linear FM pulses (FM Train). Transmissions were combined (CW/FM and CW/FM Train) in order to compare the performance of the three signals on the same basis. Experimental results on signal to reverberation ratios are presented and compared to theory.