Abstract: An electrical circuit device comprises an integrating amplifier arrangement that provides a circuit output signal in response to an input signal from a differential amplifier. The differential amplifier receives at one of its input terminals the circuit input signal and at its other input terminal the circuit output signal. The circuit limits its output signal to change at less than a predetermined rate, and the device is particularly useful in a pendulum unit of a gyroscompass, where the rate limitation can be arranged such that the compass does not respond to acceleration due to motion of the craft or vehicle in which the compass is mounted.

Abstract: A gyrocompass comprises a gyroscopic element having a stabilizing gyro with a relatively heavy rotor rigidly secured to a driving shaft and a control gyro with a rotor of lower inertia mounted on the same driving shaft as a free rotor gyro. A case enclosing the gyroscopic element and a drive motor is mounted in a vehicle with the spin axis in the north south plane in gimbals with a nominally vertical outer axis and an inner or tilt axis in the east-west plane. The stabilizing gyro is slaved to the control gyro by means of signals from pick-offs associated with the latter so as to zeroise misalignment, and the tilt gimbal is pendulous to provide a gravity reference, so that the azimuth misalignment signal between the gyros generates an opposing tilt torquer current which is a measure of the gyro tilt angle.