Abstract: A method of position measurement by processing at least two phase displaced signals and by selecting one signal for position measurement at a given position point. Specifically, the two phase displaced signals are quadrature signals and the selected signal has a more linear waveform slope relative to time at a given position point than the non-selected signal.

Abstract: A controlled force fluid delivery system which provides fluid delivery with continuity over a wide range of flow rate. The system sets the force provided by an energy storage device, e.g. a spring and the opening of system outlet valve in response to a low volume due command. Specifically at a low flow rate, the controlled force is decreased and/or the outlet valve of the system closes before the fluid flow reaches stable velocity whereas at a high flow rate the controlled force is increased and/or the outlet valve does not close until the fluid stops flowing. The system also reduces fluid flow rate variation in part by adjusting the timing and the level of opening and closing the outlet valve, and the speed of pumping the fluid out of system central cassette chamber.

Abstract: A dynamic controller for quantitative rapid-pulse flow control over a wide dynamic range (1000-to-1) forms a fluid path from a pressurized source to a sink. The fluid path travels, typically in a disposable cassette, from the pressure source via a fast (one millisecond) on-off source control valve into a volume-displacement interface area, thence to a fast on-off load control valve and on to the sink. The load control valve may be replaced by a passive flow restrictor where less dynamic range is required. From the reusable controller side, fast actuators are energized to open the normally-closed valves. A volume sensor mates with the volume-displacement interface area. This sensor uses an incompressible transfer fluid, typically different than and isolated from the deliverable fluid by membranes, to transmit volume displacement change into a transducer area for conversion from volume to a measurable electrical signal, typically a frequency.