Abstract: In a device having a synchro resolver and a microprocessor, the apparatus of the present invention utilizes a pulse excitation technique for converting a synchro output signal to a digital format. A pulsed waveform is selectively applied to the input windings of synchro resolver and output voltages are induced in the output windings. A sample and hold circuit is selectively enabled and selectively coupled to the output windings of the synchro resolver, and the sampled output signal of the output windings is converted into a digital format via an analog-to-digital converter.

Abstract: The outputs of a three-wire synchro are applied to a multiplexer which provides the multiplexed synchro outputs to an amplifier and demodulator. The demodulated synchro outputs are applied to a demultiplexer whose outputs are filtered to provide demodulated d.c. voltages corresponding to the synchro output signals. The demodulated d.c. voltages are applied to a conversion circuit for providing the sine and cosine of the angular position of the three-wire synchro device. The multiplexer, demultiplexer and demodulator are synchronized by the synchro a.c. reference signal.

Abstract: Apparatus for indicating attitude failure in an attitude indicator system in which energy is stored and isolated from all other apparatus during normal operation and transferred to the attitude indicator when attitude failure is detected, resulting in an indication of attitude failure.