RADIOMETER WITH PROGRAMMABLE NOISE SOURCE CALIBRATION

摘要

Apparatus and a method for radiometric temperature measurement comprises a radiometer receiver coupled to an antenna/calibration switch that has coupled thereto a brightness temperature signal. A driver coupled to the antenna/calibration switch controls the operation of the switch between an antenna mode and a calibration mode. An adjustable cold/warm noise source is coupled to the antenna/calibration switch to provide a calibration radiation temperature applied through the antenna/calibration switch in the calibration mode to the radiometer receiver. An output of the radiometer receiver is coupled to the adjustable cold/warm noise source and is adjusted in accordance with the output of the radiometer receiver for a null comparison measurement. Also coupled between the output of the radiometer receiver and the antenna/calibration switch is a mode selector switch that operates to a mode one position to couple the output of the radiometer receiver to the adjustable cold/warm noise source. A bias source is also coupled to the mode selector switch and actuation of the mode selector switch into a mode two position couples the bias source to the adjustable cold/warm noise source.