Frequency domain analysis of neurophysiological data

Six programs are described which constitute a Spectral Analysis Package for the Digital Equipment Corporation LAB-8 computer and a random access magnetic storage device. The programs allow a wide range of data processing to be carried out in the frequency domain on neurophysiological observation in the form of analog voltage or spike train signals. Transformations between the time and frequency domains are possible in either direction using the Fast Fourier Transform Algorithm. Commencing with two observed signals the programs permit the calculation of power spectral density, coherence, describing, auto and cross correlation functions as well as providing techniques for the averaging of successive calculations in order to improve spectral estimates. Mathematical manipulation is provided by modifications to the interpretive language FOCAL which permit powerful flexibility to operate on data in a variety of formats. All data is stored in files within the Disc Monitor System so that the programs may be used on a machine which is also serving other purposes.