Method for achieving high accuracy performance from conventional tracking synchro to digital converter

摘要

A synchro to digital converter which has a programmable read only memory (prom) that operates under control of a feed back counter and register. The prom is programmed to generate a digital signal proportional to the converter's inherent systematic error. The data stored in the prom is empirically derived by running an error (input angle vs. output angle) curve on the uncompensated converter. The corrected error signal from the prom is converted to analog form by conventional digital to analog converter means and subtracted from the closed loop steering signal which is derived from an approximating network thereby increasing the converter output accuracy to within better than 2 arc minutes.