A linear frequency transducer using a quadrature circuit†
P. V. DEO · International Journal of Control · 1970
A quadrature circuit consists of a resistance and a reactance in series. To convert non-electrical quantities, such as velocity, acceleration, pressure, temperature, etc., into frequency, this circuit is used along with a variable frequency generator. One of the components of the circuit is a parametric transducer which converts the measured quantity into the electrical parameter, such as resistance or inductance. The circuit, working as a self-adjusting device, possesses two advantages, namely, the linearity and the accuracy of measurement. The non-linearity introduced by the residuals of the quadrature circuit components has been investigated. It can be kept below a desired value by judicious selection of the components.