On-Line Frequency Analysis of Neurophysiological Data

This document is a DECUS program library write-up for two programs, OLFFT1 and FETCHFFT, developed by the Burden Neurological Institute. These programs are designed for the on-line frequency analysis of neurophysiological data (EEG) using a PDP-12 computer with at least 8K memory, a real-time clock, and A/D converters.

• OLFFT1: Handles the transformation of one to four channels of data into power spectra using the Fast Fourier Transform (FFT). It supports two modes of operation: continuous and non-continuous, with data storage on magnetic tape.
• FETCHFFT: Used for retrieving, displaying, and plotting the stored power spectra. It allows for inspection, logarithmic scaling, and printing of specific frequency components.

The manual details operational procedures, hardware requirements, memory layout, scaling factors for spectral analysis, and instructions for handling potential aliasing issues.