| 摘要 |
A vortex flow transmitter (10) has a filtering circuit (20) receiving a noise contaminated input signal representative of the flow and which has a fundamental frequency varying responsively to flow. The filter (20) filters the input signal using one of a family of HP filter characteristics. Each member of the family of HP filters has varying corner frequencies, each filter having a unique switchup and a unique switchdown value assigned to it. Adaptive response means (40) select a current HP filter for use in the filter means. The adaptive means use one selection method when the flow is increasing and another selection method when the flow decreases. Output means (52) convert the signal from the filter means into a transmitter output, typically a 4-20 mA current or a frequency output representative of the flow. |
