A variable gain control amplifier and method provides a substantially constant input impedance and output impedance, and provides a substantially constant noise figure and third order harmonic. The phase synchronizing circuit generates and outputs high-resolution absolute phase information based on the position change signals. A method of reducing power consumption by a display system in which a light modulating display modulates incident light from a light source to provide images is characterized in controlling power provided to the light source to reduce output thereof for relatively dark images. Next an application program interface is interfaced with a plurality of processes in connection with memory needed for each process.