A Continuous Spectrum Analyser for Analogue Analysis of ULF Tape Recorded Data

Abstract

A sweep-frequency spectrum analyser for Pel geomagnetic pulsations (0·2-5 Hz) is described. It utilizes a rotating head assembly with two replay heads for scanning the data tape which is transported by a standard audio frequency quarter-inch tape deck. Frequency and time resolutions of O· 1 Hz and 6 s in the Pel band may be obtained.