Abstract: A data separator for providing data and clock information derived from a floppy disk to a controller includes a synthetic oscillator phase-locked loop which adjusts the phase of the derived clock, thereby to tend to position data inputs within the central portion of their associated half-bit slots. The center frequency of the synthetic oscillator may be modified in accordance with prior phase adjustments to compensate for variations in the speed of the floppy disk drive.

Abstract: A microprocessor based CRT video display system includes a microprocessor, a memory and a video processor and controller. The video processor and controller incorporates data and address bus structure in which a plurality of programmable registers are connected to both the data bus and the address bus. The programmable registers arranged along the data and address buses permit efficient retrieval of information from memory for display and also permit the video display system to provide a number of advantageous system features.

Abstract: There is disclosed a typewriter using a single element print head wherein the tilt and rotate positions for character selection are obtained by servo systems driving tilt and rotate shafts. The system utilizes a digital multiplexing system whereby common elements in the servo channels are time shared. One common element is a binary arithmetic unit which compares binarily represented actual and desired position values of the shafts to fetch from a memory desired velocity information. The fetched velocity information in binary form is compared with the binarily represented actual velocity of the shafts to generate signals for energizing the servo motors which drive the shafts.