Abstract: Spatial light modulators (SLMs) can be amplitude-only modulated, phase-only modulated, or the pixel amplitudes can even be a function of phase. However, practical devices providing independently controllable values of phase and amplitude are not expected for some time. It has been possible to design modulation patterns for these limited range SLMs that do produce diffraction patterns similar to those possible from full complex SLMs, but hours of intensive iterative optimization usually have been required. Our approach instead develops and evaluates direct, pixel-by-pixel encoding algorithms that map the limited range modulation properties onto the entire complex plane. The advantage of these algorithms (generally recognized by the name pseudo random encoding) over iterative optimization is that designs can be performed in real-time making systems adaptable to rapidly changing situations.