Spectral analysis of stepped test cell ultrasonic spectrometer

A stepped test cell (STC) ultrasonic spectrometer has been developed for characterisation of liquids and suspensions. It enables ultrasonic propagation constants, velocity and absorption coefficient, to be measured simultaneously in a single measurement without requiring any path-length adjustment. A signal processing software was designed to compute the spectra of the two propagation constants in a frequency range of 2-10 MHz via fast Fourier transform (FFT) analysis. With the utilisation of the specially designed stepped test cell, these spectra can be computed without employing any correction procedures. Spectral measurements were carried out on rubber latex of various weight percentages of dry rubber content to investigate the performance of the developed software. The measured spectra of ultrasonic absorption and velocity were comparable to those published in the literature