EVALUATION AND MODIFICATION OF EXISTING PROTOTYPE DYNAMIC CALIBRATION SYSTEM FOR PRESSURE-MEASURING TRANSDUCERS. VOLUME 3. COMPUTER PROGRAMS

Abstract

Abstract : The Transfer Function Approximation Program (TFAP) is an IBM 7909 FORTRAN program which will compute the approximate transfer function for any linear pressure transducer system from the system's time response to a step input. Input data to the program contains information which specifies test conditions, information which defines the data range and density for the approximation, and information which specifies the amplitude of the time response at each of a number of equally spaced sample points in the time domain. Primary output data from the program contains the amplitude and phase of the approximate transfer function for the transducer system at equally spaced points in the frequency domain. With minor modifications, the program is adaptable to any problem which requires the computation of a linear system's transfer function from its time response to a known input. The program has been tested with time response data for an analytically known two degree-of-freedom system excited by a step input. The results of these tests indicate that the accuracy of the approximate transfer function is determined by the data sampling frequency and the data range. For sampling frequencies greater than twenty times the highest frequency of interest and a data range which includes the time response out to a point at which the time response has reached 99% of its final value, the approximate transfer function was found to be within .5% of its known value.