Determination of Time Delay Using Cross Correlation
Original Publication Date: 2002-Sep-01
Included in the Prior Art Database: 2003-Jul-23
Background: Pressure sensors are usually found in both the inspi- ration and the expiration branches of the gas flow circuit in a patient ventilator system. At any time in the breathing cycle there will exist a time delay be- tween pressure sensed by the different sensors. For example, during an inspiration phase the expiration sensor will measure a signal that is delayed with respect to that measured by the inspiration sensor. A ventilator is typically regulated using the combined contemporaneous outputs of these sensors, weighed dependent on the time delay. In the present system this time delay is measured only at the start of its operation but time dependant changes in the tubing system may cause this time delay to vary signifi- cantly during use.