Digital filters: a practising engineer´s perspective

Contemporary sonar systems use the ultrasonic spectrum from DC to 500⁺ kHz; up to ~100 kHz all processing is typically implemented on general purpose DSPs. Narrow transition bands, low passband ripple, high stopband attenuation, etc., are common manifestations of the high `quality´ requirements of the filters used in sonars. This paper states typical requirements for sonar filters, presents classic sonar filters as illustrative examples, considers the technique and tools available to the practitioner, and concludes with a number of hopefully stimulating assertions on best practice, current concerns and desirable developments regarding contemporary design techniques and tools