Abstract: Velocity and phase errors in signals derived from a rotating video disc are minimized with the use of a voltage controlled oscillator and an electromechanical transducer. A control circuit employing an active and a passive filter maintains an appropriate frequency response to the voltage controlled oscillator and electromechanical transducer in order to appropriately share a single controlling error signal.

Abstract: When a "locked groove" condition is encountered in the playback of a video disc having sync signal recording locations non-radially aligned in successive groove convolutions, each initiation of a repeat reading of the same groove convolution(s) results in a timing disturbance of recovered sync signals. The disturbance is detected by an arrangement employing a phase locked loop responsive to the horizontal sync component of the recorded signal. A filtered error voltage output of the phase locked loop is applied to a voltage comparator to effect discrimination against noise and minor, transitory timing disturbances. A staircase voltage generator, responsive to the voltage comparator output, provides an output sufficient to trigger generation of a locked groove recognition pulse, when the voltage comparator threshold is exceeded a sufficient number of times within a selected time period to verify locked groove behavior and continuance.