Dbm; Figure 2-10 Typical Dbm Operation Display - Agilent Technologies U3401A User's And Service Manual

2 Operations and Features

dBm

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 impedance
(typically 50, 75 or 600 Ω). The formula used for conversion from the
voltage reading is:
dBm = 10 x Log

Figure 2-10 Typical dBm operation display

The default reference impedance value is 600 Ω.. You can select the
following 21 reference impedance values:
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, 8000 Ω..
The dBm operation can be applied to DCV, ACV and DCV + ACV
measurement functions only. The multimeter displays the dBm modifier on
the primary display and displays the reference impedance selection on the
secondary display.
Procedure 1
1 Press
2 Use
3 Press
38
[1000 x (Reading
10
to enter dBm modifier mode.
and to select the desired reference impedance.
to enable the dBm operation and read the display.
2
/ reference impedance)]
U3401A User's and Service Guide