Abstract: A controller (800) for a pulse width modulated display system. The controller (800) periodically determining the output of a light source by sampling the output of a light detector (808) an creating a smoothed approximation of the periodic waveform of the light source. A processor (806) in the controller (800) reads a base bit split sequence from a read only memory (804) and modifies the sequence by lengthening or shortening the bit periods described therein in order to compensate for the periodic variations of the light source. The modified bit split sequence is stored in two-port random access memory (802) where it is later accessed by both the processor (806) and a sequencer (304). The sequencer (304) reads the modified bit split sequence from the two-port random access memory (802) to determine when to load each bit of image data into a modulator an-ay.