A programmable sonar signal processor

A 36-channel digital sonar processor has been designed and constructed based on computer simulation results. For CW pulse operation, 16 stored doppler replicas in ROM units are used for correlation with the received signal. For FM pulse operation, a hard limited replica stored in a ROM is used to correlate with this received signal. The advantage of processing the signals in this way is that the replicas can be adjusted to change the effective filtering characteristic. For example, increasing the length of the stored replica reduces the effective bandwidth. Also, replicas can be changed with range or provide different doppler selections for different beams. Experimental results using ideal and real signals are provided.