Abstract: A method and apparatus for increasing the resolution and accuracy of flow measurements made by vortex flowmeters. A signal conditioning circuit connected to a vortex sensor generates a vortex signal having a period that varies with the frequency of the vortex street. The period of this vortex signal is measured by a period sampling circuit, which generates a vortex period signal. When a programmable control circuit determines that the change in the frequency indicated by successive values of the vortex period signal is relatively small, the displayed flow value is based on the current frequency of the vortex signal; when the change in frequency indicated by successive values of the vortex period signal is relatively large, the displayed flow value is based on the running average frequency of the vortex signal.