| 摘要 |
A time-of-flight flow sensor, of the type in which a measured phase difference between upstream and downstream acoustic propagations is representative of fluid flow rates, is operated at two distinct frequencies. Operation at a relatively low propagation frequency yields a first phase difference signal that is unambiguously representative of the rate of flow but that has a larger than desired measurement error. Operation at the higher frequency provides a lower measurement error, but may be ambiguous because of the modular nature of phase detectors. The low frequency phase difference signal can be used by a signal processor to determine a compensation term that can be combined with the higher frequency phase difference signal to remove the phase detector ambiguity, if one is present.
|
