Abstract: Circuitry for producing the signals necessary for driving and controlling a synchro-resolver is disclosed. The circuitry includes a reference generator (84) which is driven by an AC reference signal and thus, the resulting output DC reference voltage on line (82) is locked to the AC reference signal. The DC reference voltage is then combined with a computer generated digital command signal by a MDAC (Multiplying Digital to Analog Converter) (74) to provide a control signal which varies around a selected reference level. A pulse-width modulator (112) provides a high frequency square wave output which square wave is pulse-width-modulated by the AC reference voltage. The pulse-width-modulated high frequency square wave is then provided to an amplitude modulator circuit (106) where the high frequency square wave is itself amplitude modulated by the control signal.

Abstract: A simulated open circuit on high current electrical lines is generated, such that high currents, including transient currents, do not interact with and adversely effect the low current digital computer electronics which control the simulation. A bi-directional triode thyristor in its non-conducting state is triggered to enter its conducting state allowing current to flow through the thyristor and to trip a circuit breaker connected to the output of the thyristor. The tripping allows the thyristor to reset itself to its non-conducting state and to be ready for any new triggering signal.