Remote state measurement, e.g. of complex impedance temp., pressure or humidity sensor - analysing voltages across sensor and series circuit contg. sensor and other components and forming quotient or difference of stored complex amplitude and phase of frequency components

摘要

A sensor in the form of a complex impedance is placed in series with circuit elements of selected types. Pulse voltages are applied to the series circuit. The amplitude and phase of the intensity distribution of frequency components of the total voltage across the series circuit, and of the same components across the circuit elements, are measured and separately stored. The complex impedance of the sensor is derived from the quotient or difference of the stored complex frequency components. USE/ADVANTAGE - Eg for plate capacitor eg of vehicle seat, body work, passenger space, tank, acceleration sensor or strain gauge. Universally applicable and involves low circuit costs. Accuracy is independent of external parameters.