An absolute encoding system is provided based on an incremental optical encoder which, together with a low power circuit technology and means for pulsing the light emitter(s) of the encoder (normally the largest power consuming device(s) in such a system) with a signal of low duty cycle and means for sampling the light detector outputs during the appropriate period of response to the emitted light pulses, produces an encoder system having extremely low internal power consumption allowing not only data retention but also data acquisition during periods of isolation from an external power supply by relying on its own relatively small battery-based power source.