Digital to analog interface conversion circuit

DETAILED DESCRIPTION In accordance with the invention there is provided an interface circuit for use in connecting a rotation sensor and its associated electronics having a digital pulse output to a rotation measuring system for use with a spinning mass rotation sensor.
For purposes of this disclosure, the term "associated electronics" means conventional electronics used to provide loop closure for the rotation sensor and condition the sensor outputs to provide digital pulsed outputs where the pulses represent incremental clockwise and counterclockwise rotation.
The interface circuit includes a first switch for receiving clockwise pulses from a rotation sensor and its associated electronics, such as a fiber optic gyroscope, which pulses are indicative of changing angular position in one direction.
The switch serves to apply a predetermined voltage to a summing integrator for an amount of time equal to the width of the pulses received from the rotation sensor and its associated electronics indicative of changing angular position in a specific direction.
A second switch serves the same purpose as the first switch but is for receiving counterclockwise pulses from the rotation sensor and its associated electronics.
This switch also applies a predetermined voltage to the summing integrator for an amount of time equal to the width of the counterclockwise pulses received from the rotation sensor and its associated electronics.
A convertor receives a command signal representative of change in angular position commanded to a platform on which the position sensor and its associated electronics is mounted, and serves to convert the signal to a voltage proportional to the voltage applied by the first and second switches.
The convertor also supplies the converted signal to the summing integrator.
The summing integrator then receives the three voltages from the switches and converts and sums the voltages to generate an error output in volts per degrees per second when the command signal is not equal to the converted output from the rotation sensor and its associated electronics