Correction - circuit arrangement for geometric deflection errors of a television camera roehre

摘要

A vertical-rate sawtooth waveform amplitude modulates a train of horizontal-rate pulses. Positive and negative pulse clippers receive the pulse train. One generates a clipped waveform during the last half and a zero output for the first half, of a television field. The other generates a clipped waveform during the first half and a zero output the last half of the field. A pair of AC coupled integrators, driven by respective clipped waveforms, generate horizontal-rate sawtooths which are linearly modulated, one from a maximum at the beginning of the field to zero at the center thereof, and one from zero at the center to a maximum at the end of the field. Two pairs of clippers separate the two sawtooths into four half-sawtooths, wherein each is active in a time interval corresponding to respective quadrants of the picture raster. Potentiometers are used to vary the respective waveforms to allow independent correction of the scan in any corner.