Description:
<jats:p>A theoretical model and a computer simulation of a generalized approach to the synthesis of random noises were presented in an earlier paper [K. D. Hsueh and R. P. Hamernik, J. Acoust. Soc. Am. Suppl. 1 85, S40 (1989)]. In this paper, the hardware implementation for this new synthesis technique is described. The digitally generated analog signals transduced through a high-intensity acoustic driver show that manipulations in the phase domain can be advantageous in creating acoustic signals of widely varying descriptors (e.g., skewness, kurtosis, etc.) while maintaining identical amplitude spectra. In essence, entire families of random waveform having identical amplitude spectra but variable statistical properties can be created. The influence of the acoustic driver on the spectra and the statistical properties of the synthesized waveforms will be shown. Some examples of the flexibility of phase manipulations will be presented, e.g., (1) amplitude-modulated random phase and (2) convolutions of the synthesized waveforms with any arbitrary function. These results illustrate that a variety of phase manipulations can be performed to produce interesting families of complex random waveforms. The application of this methodology to acoustic or vibration testing, environmental stress screening, psychoacoustic studies, etc., will be discussed. [Work supported by NIOSH.]</jats:p>