Abstract: Electrical and mechanical synchronization of two or more synchronously driven gyroscopes, mounted on the same platform, to minimize cross-talk induced drift, is achieved by bringing one gyroscope to a speed which is slightly higher than the other by driving it at a slightly higher frequency. At speed, coincidence of mechanical position is established by means of signals from pick-offs on each gyro and the drive for the faster gyroscope is shifted to the lower frequency. Electrical synchronism is established by restarting the lower frequency generator to instantaneously establish a predetermined relationship between a pick-off signal and the frequency generator. Phase-lock start-up of a single gyroscope by instantaneous shift of the phase of the driving voltage, relative to the gyroscope wheel position, is also provided.

Abstract: A switching circuit turns on at the beginning of a first clock signal and turns off in response to a gyroscope shaft detector signal. During the time the switching circuit remains on, a counter counts the cycles of a second clock signal. This resultant count is employed as an error signal for adjusting the output frequency of a pulse generator which is connected to a gyroscope motor. A feedback loop is created between the aforementioned components for achieving a preselected constant gyroscope motor speed.