Patent ID: 7966141

Claim:
A method for evaluating and correcting a total measurement signal (TS(n)) of a measuring device working according to a travel-time measuring method and applied for ascertaining continuous fill level of a medium in a container, comprising the steps of: transmitting and receiving measurement signals during a measurement cycle toward the medium and reflected on a surface of the medium as wanted echo signals or on a surface of a disturbing element as interference echo signals; producing an intermediate frequency signal, from a total measurement signal having a frequency higher than the intermediate frequency signal, the total measurement signal being composed of the superposition of the transmitted measuring signals, the reflected, wanted echo signals, and the interference echo signals, by a sequential sampling; determining, from the intermediate frequency signal, at least one raw echo curve or digitized envelope curve as a function of travel time or travel distance; wherein the interference echo signals in the raw echo curve or digitized envelope curve are ascertained in a current static reference curve and stored; ascertaining an independent reference curve, in the case of a modification of at least one technical, process condition in the container and/or a modification of at least one technical, measurement condition of the measuring device on the basis of the current static reference curve; and masking out the interference echo signals out of the raw echo curve on the basis of a masking algorithm, which applies said independent reference curve.