TAD Digital Quadrature Detection and Its Application to Magnetic Sensing

Abstract

This paper describes the time analog to digital converter (TAD), the TAD digital quadrature detection (TAD-DQD) technique, and their application to magnetic sensing. In-phase and quadrature components of an input signal are obtained by performing only addition and substitution operations on the data digitized by the TAD, using a sampling clock whose frequency is four times higher than the carrier frequency. Application of TAD-DQD to the position sensors using magnetoelastic waves in amorphous wires improves their resolution. TAD-DQD also simplifies the circuits of digital-output fluxgate sensors.