Automotive Hall sensor rotary encoder reference design

This is an incremental rotary encoder that uses contactless magnetic sensing to detect rotational speed and direction.  The two Hall Effect sensors measure the 66-pole ring magnet and output two signals in quadrature.  This automotive-qualified solution is a low-cost and far more reliable alternative to conventional mechanical contact-based encoders, as it uses solid-state sensing that is immune to physical wear, dirt, corrosion, and RF noise.