Raster deflection signal generation apparatus.

摘要

A raster deflection signal generator that generates deflection signals in accordance with sweep control signals provided by a programmable timing generator (14). The programmable timing generator (14) stores digital signals representative of the desired sweep control signals so as to tailor the sweep timing to the input video channel. The digital sweep control signals are synchronized (13) to the input video channel by locking a horizontal sync pulse generated by the programmable timing generator to the horizontal sync pulse of the video input channel by a phase locked loop. Each deflection sweep is compared to a threshold voltage (VCENTER) representative of screen center within a sweep generator (16, 17) to provide a duty cycle signal in accordance with drift of the TV image from screen center. The duty cycle signal is filtered and sampled and fed back to the sweep generator so as to maintain the deflection sweeps properly centered.