The use of digital techniques to improve modulation-type sectorscanning sonar systems

The methods by which the local oscillator signals for use in a modulation-type sector-scanning sonar system may be produced are briefly reviewed. To achieve good performance in practice, it is often necessary to incorporate many adjustments in the system. An alternative system employing mainly digital techniques is considered, the analysis of which reveals the potential for improvements in performance. A sector-scanning sonar requiring few adjustments has been constructed using these techniques.