Time (min)
E'rci. IN. Hpol~ta~lt.occs c~cLiviticw ~r~c:ortlv~l S ~ I I I I I ~ ~ ~ L I I I ! ~ I I I ~ ~ ~
fr,]rn t h ~ ,
I~IIIIS of 11 t10a1.L of
(?io~~cc lignt.urt~cl ill thcl rnitltllcr. It~Ic~rl)~~tit i~~l(-~.vtiId ( I * I . I ~ ~ I I I L ~ . c ~ )
w11ru 1~Ii1111!tI ngnif~st.
t,itncr (nk)wcinra). l'h~! visnvrtd tsr~tl (c.I~~xc.rl oirct11.s) wtrs ch~rraat,oriv~!cl hy rngulnrly
varying lovcrln of high aticl low f r o r ( ~ ~ o ~ ~ c y ;
in thiu prcr()nrrtt,i~)n hypc~t~rnnahial c!nrl
(open oirnlex) vctrit3tl I I I O ~ A OI, IOHH rogulnrly I~ot.wtv~t~ 1nvel.i of high ant1 low frequency
but, with Iongor perir~cis of lligh froq~icmcy than thoso of the vixooral end. (Reproducud, wiBh permission, fro111 Anderson, 1968.)