| 摘要 |
PURPOSE:To perform a high-precision temperature correction processing with less number of noise sources, by connecting automatically a low noise source, a standard noise source, and plural loss circuits selectably in the microwave radiometer mounted on an aritificial satellite or the like. CONSTITUTION:The signal received in a receiving antenna 1 is inputted to a switch B9 through a switch A8 and is switched to the signal from a comparison noise source 4 at a constant frequency and is amplified by a receiver 5 and is inputted to a comparing circuit 15 through a square-law detector 6 and a synchronous detector 7. A low noise source antenna 2 where the noise temperature is known, switches D13 and E14 to which loss circuits 11 and 12 are connected, and a switch C10 to which a standard noise source 3 monitoring the temperature are connected to the switch A8. On a basis of a detection voltage of a measured noise temperature, switches 10, 13, and 14 are switched through the comparing circuit 15 by a control circuit 16 to generate an optimum correcting noise source, and it is inputted to the switch A8. Thus, 5 correction points are generated with one standard noise source. |
