Abstract: Apparatus is disclosed for controlling the movement of a movable element to bring said movable element to rest at a desired stopping position. The apparatus comprises a multi-phase drive motor having a drive shaft coupled to the movable element for driving same, a plurality of electrically conductive coils mounted in position-displaced relationship about the shaft, and means coupled to the drive shaft and responsive to the selective energization of the coils by respective motor drive signals for causing the corresponding rotation of the drive shaft and movement of the movable element. A sensor is coupled to the drive shaft and is responsive to the rotation thereof for generating an electrical signal containing information indicative of the direction, speed and distance of movement of said movable element. Further, means are included for detecting from the distance information indicated by the electrical signal whether the movable element is within a predetermined distance of the desired stopping position.

Abstract: A motor speed control system for reducing instantaneous speed variations as a result of hunting in hysteresis synchronous motors utilized to drive optical scanners by controlling the frequency of the drive signal applied to the motor. A laser beam is reflected from the facets of the optical scanner and scans a surface along a scan line, a signal being generated at the start and end of each scan line. A counter is driven by an accurate clock which is started and stopped in accordance with the start and end of scan signals. The resulting count of the counter is thus inversely proportional to the speed of the motor and is converted to an analog input signal and coupled to a voltage controlled oscillator whose frequency is controlled for driving the motor such that undesirable oscillations of the motor are damped out. Additional embodiments for controlling the motor speed are disclosed which utilize only the start of scan signal to both start and stop the counter.

Abstract: A high-speed printer with a printing wheel with the individual type elements supported by radially extending spokes. Separate servo systems provide intermittent movement for the printing wheel and the carriage carrying the printing wheel.

Abstract: A system for generating video information on a display medium which is characterized by a character generation of high quality, variant font definition, and font character off-set. The character generating means within the system provides means for selecting an external video source to be displayed alternative to the output from the character generator itself.