Abstract: 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.

Abstract: A high accuracy digital to analog resolver converter uses a read only memory device (PROM) programmed to generate a digital signal proportional to the inherent systematic error of a digital to analog resolver converter. This signal is then converted to analog form by conventional means and combined with the primary signal in analog form thereby substantially increasing the accuracy of a digital to analog resolver converter.