Design Device
by Tom DeWitt, 1975 (part 11 of 18)
The Outline Generator will consist of an edge triggered single shot with variable pulse width. This single shot will be fired on two conditions: 1) when there is a level change on a comparator looking at the video input; 2) when there is a level change on a comparator looking at the difference between the incoming signal and a one line delay of the incoming signal. The delay line to be used is identical to that used in the one bit time base corrector.
The four Multipliers on the Design Device are four quadrant multipliers developed for modular synthesizer use by Steve Rutt. The voltage of their outputs is equal to the product of their two inputs. Hence they can be used for amplitude modulation, polarity inversion, and frequency doubling.
The RuttEtra Display system to be used on the first Design Device is a Model 4A Display built in 1974. The rescan camera will be a studio G.E. vidicon being donated by WMHT from surplus stock. The Display will have two buffer amplifiers with manual bias control and an intensity compensated video amplifier.
The two keyer circuits on the Design Device are based on identical circuits. The major difference between them is that Keyer One will use a single signal as both a key and video
The inverter circuit consists of a high speed op amp and is intended for reversing polarity of a video signal while maintaining its black level clamp.
The Voltage Controlled Mixer is based on the MC 1445 integrated circuit. It can be used as a two quadrant multiplier, a video mixer, a keyer, a transparent keyer, a pulse width modulator and a voltage controlled amplifier. Detailed construction designs
Parts
