Abstract: A method cleans a plurality of filters in parallel, each filter having an inlet side and an outlet side separated by a filter barrier. In an operational phase, water is filtered using a plurality of the filters, by passing the water through the filter. In a cleaning phase, at least one of the filters is cleaned while the other filters are filtering water in the operational phase. Each filter is cleaned by supplying sodium hypochlorite to an inlet side of the filter when the filter is off-line. The inlet side of the filter is allowed to soak in the sodium hypochlorite for at least 30 seconds without the sodium hypochlorite being pressurized through the filter barrier during the soaking process. The filters are cycled through the cleaning phase such that each filter is repeatedly cleaned while other filters are filtering in the operational phase.

Abstract: An active sonar detection system may include a transmitter, which may project into the transmissive medium signals of any frequency, amplitude or phase using one or more transducers. A transmit beamformer to provide transmission directionality may also be included. Generated transmit waveforms may have different temporal and frequency spectra that are adapted for different purposes.