Rigol DS6104 - Page 5

RIGOL TECHNOLOGIES USA INC
877-4-RIGOL-1 How-To Guide
info@rigol.com
www.rigolna.com

IfyouchangetheunitstodBVrms,herearethevalues:

Whenthesettingsare20dBVrms/divandthereferenceismovedtoone
divisiondownfromthetopoftheFFTdisplay:

Divisionsdownfromtop
ofFFTscreen
dBVrmsfromposition
marker
Valueattopofthat
division
0 +10dBVrms 3.16Vrms
1 0dBVrms 1Vrms(attheposition
marker)
2‐10dBVrms .316Vrms
3‐20dBVrms .1Vrms
4‐30dBVrms .0316 Vrms
5‐40dBVrms .01 Vrms
6‐50dBVrms .00316mVrms
7‐60dBVrms .001 mVrms
8‐70dBVrms .000316mVrms

Tounderstandthisfully,theformulatoderivethedBVrmsvalueisasfollows:
dBVrms=20*log(Vrms/VREF)

 whereVREFinthiscaseis1Vrms,soitcanbesimplifiedto:

dBVrms=20*log(Vrms)

Consequently,whenlookingataspotonthescreenthatisknownto
beX
dBVrmstheactualVrmsvalueexpressedbysignalatthatlocationis:

Vrms=10^(X/20)
Forexample,‐20dBVrms=10^‐1=0.1Vrms