User`s guide

Functions and Features 2
34450A User’s Guide 41
Editing dBm measurement
The logarithmic dBm (decibels relative to one milliwatt)
scale is often used in RF signal measurements. The
multimeter’s dBm operation takes a measurement and
calculates the power delivered to a reference resistance
(typically 50, 75, or 600 Ω). The formula used for conversion
from the voltage reading is:
dBm = 10 × Log
10
[(Reading
2
/ R
REF
) / 0.001 Ω ]
You can choose from several reference resistance values:
R
REF
= 2 Ω, 4 Ω, 8 Ω, 16 Ω, 50 Ω, 75 Ω, 93 Ω, 110 Ω, 124 Ω,
125 Ω, 135 Ω, 150 Ω, 250 Ω, 300 Ω, 500 Ω, 600 Ω, 800 Ω,
900 Ω, 1000 Ω, 1200 Ω, or 8000 Ω.
You can view and select the reference value as described in
“Editing math functions reference values” on page 42.
Select dBm option
dBm measurement
Ongoing measurement
Reference value
Press to exit
1
4
2
3
Press to start