Analog quadrature signal to phase angle data conversion by a quadrature digitizer and quadrature counter

摘要

The quadrature phase angle &phgr;(t) of a pair of quadrature signals S. sub.1 (t) and S.sub.2 (t) is digitally encoded on a real time basis by a quadrature digitizer for fractional &phgr;(t) rotational excursions and by a quadrature up/down counter for full &phgr;(t) rotations. The pair of quadrature signals are of the form S.sub.1 (t)=k(t) sin &phgr;(t) and S. sub.2 (t)=k(t) cos &phgr;(t) where k(t) is a signal common to both. The quadrature digitizer and the quadrature up/down counter may be used together or singularly as desired or required. Optionally, a digital-to- analog converter may follow the outputs of the quadrature digitizer and the quadrature up/down counter to provide an analog signal output of the quadrature phase angle &phgr;(t).