Transducer output signal processing using an eight-bit microcomputer

Procedures for dealing with calibration data involving a disturbing variable using an 8-bit microcomputer are described. An interpolation polynomial with coefficients that are themselves polynomials in the disturbing variable is fitted to the calibration data and is used in two alternative ways. In the first, the polynomial coefficients are stored in the read-only memory of the microcomputer and direct computation is used to obtain the primary variable from the incoming data. In the second, the interpolating polynomials are used to generate an equispaced 2-D look-up table that is stored in the read-only memory of the microcomputer. A 2-D interpolating routine is then used to obtain the value of the primary variable from the incoming data. A comparison of the two methods with respect to computation accuracy, speed of operation, and memory requirements is presented, and the procedure for extending these techniques to the case of two disturbing variables is discussed.