Drive techniques for a digital flowmeter

Drive techniques for a digital flowmeter are described. The drive techniques account for delays caused during digital signal processing of sensor signals that correspond to a motion of a flowtube, as well as drive signals that impart motion to the flowtube. Such delays may be caused by a variety of factors, including delays associated with analog/digital conversion of the signals and/or filtering of the signals. The techniques include open-loop techniques and closed-loop techniques, which can be used separately or together during the start-up and operation of the digital flowmeter. Startup and operational techniques for a digital flowmeter also are described. The startup and operational techniques select an optimal mode of operation for the digital flowmeter, depending on a current environment of the flowmeter, where the mode of operation might be chosen from, for example, a random sequence mode, a positive feedback mode, or a digital synthesis mode. In either the positive feedback mode or the digital synthesis mode, the digital flowmeter may revert to a previous mode to regain stable and desired oscillation of the flowtube, such as might be required during a recovery operation associated with a disturbance to an operation of the digital flowmeter.