Abstract: An apparatus and method is presented to provide wide dynamic range balanced measurements of the input phase to an interferometer using a phase generated carrier especially useful utilizing time multiplexing to demodulate a series of interferometers with high accuracy. A modulation drive output is provided by the invention and maintained under operation at the optimum amplitude by an internal feedback loop. The resulting highly stable system which is time balanced, can be fabricated from an analog to digital converter, a digital signal processor, and a digital to analog converter making low cost open loop demodulators a reality.