A quantitative echo sounder includes delay circuits, phase correction circuits, an incidence angle calculator and a directivity correction unit. The converter control method includes, in each cycle, a first phase of first duration with first switch controlled to make it conductive, and to increase current in the induction coil, and a second phase with second switch controlled to be conductive and to decrease current in the induction coil during a second adjustable time period. The fluid carrying conduits link the oxygen source to diseased sites within the patients lungs. In the event a UNDI driver is found, a PCI network device that is associated with the UNDI driver is scanned for. The installation guide may be configured to properly align the frame and the first grounding fiber relative to the rotatable motor shaft.