Broadband doppler simulator

摘要

A broadband doppler simulator is described in which signals from a plurality of hydrophones are simulated by selecting storage addresses of a random access memory whose successive addresses contain samples of an input signal. The range of each hydrophone from the target whose signal it is receiving is determined by the address assigned to the hydrophone relative to the address of the input signal in the random access memory. In order to produce a doppler shift (time compression/expansion), the address of the simulated hydrophone signal is changed with respect to the signal which is being stored in the memory. The rate at which the address of the simulated hydrophone signal is being changed relative to the input signal determines the doppler shift. In order to reduce the size of the random access memory while retaining the ability to change the apparent doppler shift with a higher resolution as well as maintain signal distortion below an acceptable limit, an interpolation technique is used to obtain signals corresponding to delays which are smaller than the delay between adjacent addresses.