On-Line Digital Spectral Analysis

Abstract

The paper describes a straightforward spectral analysis system using the fast Fourier transform algorithm and an on‐line digital computer in the laboratory. The technique is backed by a sound mathematical foundation and yields directly both components of the cross spectrum for a process measured at two points as well as the power spectrum at either point. For a potential user, certain of the details of implementing the system are included. A specific example, that of correlating density fluctuations in a plasma, demonstrates the sensitivity of such a system.