Fourier-Transform Technique for Measuring Terminating Impedances
Robert K. Plunkett, L E Wittig · The Journal of the Acoustical Society of America · 1965
The mechanical impedance at the termination of an elastic bar is found from the Fourier transforms of pulse shapes incident upon and reflected from this termination. The transform integrals were evaluated by a digital computer. The termination impedance so obtained is compared with impedance measurements made at the actual termination with an impedance head and driver. Experimental advantages and disadvantages of this technique are discussed, along with the limitations inherent in making measurements by this method. Direct engineering application is demonstrated by the use of an 1 beam as a waveguide terminated with a structural configuration. Good results are highly dependent upon obtaining accurate waveforms. [Work supported by U. S. Navy, Bureau of Ships (Code 345).]