A novel approach to image distortion compensation due to the east-west pin-cushion effect and tube-related defects is presented as an independent peripheral in an 8-bit monitor-oriented microcontroller. It consists of digitally generating a customised compensation function by storing 256 coefficients related to the pin-cushion effect and tube defects during the monitor fabrication and sequentially sending them during normal operation to a D/A converter whose output is added off-chip to the deflection voltage. This flexible solution brings compensation to tubes normally considered as defective due to departures from an ideal parabola correction when handled by conventional analogue approaches, greatly simplifies the deflection circuit and supports any current monitor standard with a minimum CPU overhead.
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