SIGNAL-PROCESSING SOFTWARE FOR TEACHING AND RESEARCH IN PSYCHOACOUSTICS UNDER UNIX AND X-WINDOWS

A package of software is described that generates, analyzes, stores, a nd displays sampled waveforms. The package is designed for use under U NIX and includes C source code, UNIX manual pages, and tutorial docume nts. The programs interact via UNIX pipes using an ASCII-text data for mat, which enables the user to view the data in numerical form as well as through the use of plotting programs. Among many other functions, the programs can do the following: efficiently generate linear-phase F IR filters with arbitrary transfer functions; generate impulse respons es for rectangular rooms of specified dimensions; convolve waveforms w ith each other; perform Fourier transformation and inverse Fourier tra nsformation; filter waveforms in the Fourier domain; filter waveforms according to the peripheral frequency selectivity of the human auditor y system; cross-correlate waveforms; autocorrelate waveforms; synthesi ze complex waveforms, including vowel sounds and white noise. The soft ware can read and write a variety of commonly used waveform file forma ts. The data can be plotted on an X-Window display using the gnuplot s oftware, which has been included in the package. The complete software package is available via anonymous ftp from ftp.ihr.mrc.ac.uk in simi lar to ftp/pub/johncu/wave.tar.Z