A microwave radiometer with an extended signal measurement range

A microwave radiometer for measuring high effective antenna temperatures us ing the modified zero receive method is described. This radiometer controls the input signal by adjusting the duration of the reference noise signal. Based on this signal duration, an antenna signal is determined. The modific ation of the radiometers is analyzed, and two signal combinations are chose n for modulation in the radiometer receiver, which is characterized by a li near dependence of the pulse-duration modulated reference signal on the ant enna signal, allowing one to measure signals in different ranges. Block dia grams of the radiometer input and control units are given, allowing one to double the measurement range by an automatic selection of the modulation si gnal combinations without a decrease in accuracy.