US Patent 9335403 Optical distance measurement device

A sensing device comprises a transmitter and a receiver. The transmitter repetitively emits a modulated electro-magnetic signal and the emitted signal interacts with an object producing a counter propagating return signal. The return signal is detected and converted into digital signals by the receiver via a reception channel through the use of edge transitions rather than logic levels from one or more comparator outputs to reconstruct the return signal waveform. Waveform acquisition and reconstruction are based on edge sampling. Methods of providing optical feedback using a moving waveguide in time-of-flight distance measurements are also disclosed.