초록 ▼

A method and apparatus for processing a time domain reflectometry (TDR) signal having a plurality of reflection pulses to generate a valid output result corresponding to a process variable for a material in a vessel. The method includes the steps of determining an initial reference signal along a pr

A method and apparatus for processing a time domain reflectometry (TDR) signal having a plurality of reflection pulses to generate a valid output result corresponding to a process variable for a material in a vessel. The method includes the steps of determining an initial reference signal along a probe, storing the initial reference signal as an active reference signal, periodically detecting a TDR signal along the probe in the vessel, and computing the output result using the TDR signal and the active reference signal. The method also includes the steps of determining an appropriate time for updating the active reference signal, automatically computing an updated reference signal at the appropriate time, and overwriting the active reference signal with the updated reference signal for use in subsequent computations of the output result.

대표청구항 ▼

[ What is claimed is:] [20.] An apparatus for processing a time domain reflectometry (TDR) signal having a plurality of reflection pulses to generate a valid output result corresponding to a level of a material in a vessel, said apparatus comprising:means for determining an initial reference signal

[ What is claimed is:] [20.] An apparatus for processing a time domain reflectometry (TDR) signal having a plurality of reflection pulses to generate a valid output result corresponding to a level of a material in a vessel, said apparatus comprising:means for determining an initial reference signal along a probe;means for storing said initial reference signal as an active reference signal;means for periodically detecting a TDR signal along said probe in said vessel;means for calculating and storing a baseline signal using said TDR signal and said active reference signal;means for detecting a level reflection pulse on said baseline signal;means for computing said output result based on the position of said level reflection pulse on said baseline signal;means for determining an appropriate time for updating said active reference signal which includes means for determining if said level is stable;means for automatically computing an updated reference signal at said appropriate time; andmeans for overwriting said active reference signal with said updated reference signal for use in subsequent computations of said output result.