Experimental spherical near-field antenna test facility. Volume 2: Data collecting and controlling system. System description and software

The design and construction of the software in a data collecting and controlling system is described, for the experimental spherical near field antenna test facility developed jointly by ESTEC and Electromagnetics Institute, the Technical University of Denmark. The data collecting and controlling system is based on an Intel microcomputer system. By means of an external bus system and external logic the microcomputer may trigger and read data from the displays (phase and amplitude displays) of the receiving system. The microcomputer also controls the positioning of the antenna probe tower by connections to the antenna positioner servo system and to position displays. Included in the system is a magnetic tape transport and formatter for the purpose of data storage. The external devices are accessed by the microcomputer by memory read/write operations. The execution time of instructions comprising memory read/write to the external devices exceeds the time for internal read/write operations by only a few microseconds.