A fully integrated timing generator for the picturephone video-telephone camera

All the timing intervals necessary for a video-telephone camera have been derived from a multivibrator oscillator by a digital process. These include camera blanking, horizontal and vertical sync, sweep triggering, clamp disable, and locked 2:1 interlace. The timing generator consists of a multivibrator and a pulse-delaying circuit using tantalum integrated RC timing elements and silicon integrated circuits. Output signals are derived digitally using resistor-transistor logic, which best meet the requirements of small size, low power, and producibility while providing adequate noise margin. These logic design considerations are discussed. The complete timing generator has been realized using five beam-leaded silicon and two tantalum integrated circuits including 217 transistors, 345 resistors, and capacitors totaling 4000 pF, all mounted on one square inch of ceramic.