Patent ID: 6867729
Filing Date: 2005-03-15
Classification: G01F,G01S

Abstract:
1. A guided wave radar transmitter comprising: a probe defining a transmission line and including a target marker above an expected sensing region of the probe, the target marker having a smaller impedance change on the transmission line than impedance chance of a material being sensed; a pulse circuit connected to the probe for generating pulses on the transmission line and receiving a reflected signal from the transmission line, the reflected signal selectively including a target pulse representing the target marker and a level pulse representing material along length of the probe; and a controller operatively connected to the pulse circuit, the controller normally operating at a first select gain to determine a level time to the level pulse to determine material level, and periodically operating at a second select gain to determine a target time to the target pulse, the second select gain being higher than the first select gain, the target time being used to compensate the level time for properties of vapor above the material level.