Calibration: Hardware Schemes

In this section, hardware solutions to the problem of calibrating the MMA amplitude and phase are described. Both solutions use the blocked area in the center of the subreflector as the source of radiation from either a two-temperature load or a cohere nt signal source. A simple mirror mechanism is used to select between the two systems. The coherent source may be made phase stable through a round-trip measurement scheme so raising the possibility of continuous phase measurement and correction as well a s providing a valuable trouble shooting tool.