Abstract: Transistor motor control incorporates a transistor bridge circuit for controlling application of power to a DC motor for forward and reverse rotation. The speed of the motor is controlled by pulse modulation, under the control of a digital counter. The counter produces a voltage stair-step waveform which is compared with a feed-back voltage. The direction of motor energization is controlled by the sign of the feed-back signal, and the transistors of the bridge are inhibited for at least one cycle prior to reversing direction.

Abstract: A digital resolver incorporates an adder for periodically and repetitively calculating the sum of two operands, one of which is increasing and the other decreasing at a rate determined by the excitation frequency of a resolver. The phase of the one of the operands is responsive to the angular position of the resolver rotor, while the phase of the other operand is responsive to forward and reverse command pulses. The sum produced by the adder is zero when the resolver assumes its commanded position, and at other times identifies the magnitude and direction of the resolver error. A digital-to-analog converter is provided for converting the error signal to an analog voltage.