Abstract: A control device for a film or tape transport comprises a control knob having a spindle which forms the rotor of an electric motor. The control knob is spun by the operator to generate a drive signal to advance or retard the film or tape driven by the transport system at a speed dependent on the speed of rotation. The rotational speed is sensed and a signal dependent thereupon is produced by a speed detector to control a servo-loop which drives the electric motor. The motor drives the control knob at substantially the same speed imparted by the operator without any further input by the operator. The control knob continues to be driven at this speed until the operator manually accelerates or decelerates the control knob.

Abstract: Compensation for phosphor burn in a CRT scanner is achieved by offsetting the scan by half a line spacing on alternate scans when the film is stationary in the scanner. To avoid unpleasant effects the offset scan output is supressed and the previous frame output frozen in the frame store 24. The previous frame is output again from the frame store in place of the offset scan output.Offset scanning is not performed when a control adjustment is made to avoid a juddering effect on the displayed output.