Correction of pincushion distortion in TV receiver - is effected by modulating horizontal sweep current by vertical deflection frequency

摘要

Pin cushion distortion of the image on a television screen is corrected by modulating the horizontal sweep current in the sweep coils by the vertical deviation frequency. A horizontal sweep generator drives horizontal deflection coils and is coupled to a modulating circuit. The modulating circuit is connected to a vertical sweep generator whose output is made non linear to provide parabolic modulation for the horizontal sweep at the vertical sweep frequency. A reactive load circuit produces a waveform at the horizontal sweep frequency and switching circuits convert this waveform to exponential form having a width equal to the horizontal flyback pulse.