Keysight U1252B - Decibel Display

Functions and Features 3
Keysight U1251B and U1252B User’s and Service Guide 85
Decibel Display
The dBm operation calculates the power delivered to a reference resistance
relative to 1mW and can be applied to DC V, AC V and AC + DC V measurements
for decibel conversion. The voltage measurement is converted to dBm by using
the following formula:
The reference resistance may be selected from 1~9999  in Setup mode. The
default value is 50 .
The decibel of voltage is calculated with respect to 1 V. The equation for the
voltage measurement is as follows:
dBV = 20 log
10
Vin
1 At the , or rotary switch position, press to
scroll to the dBm measurement on the primary display. The secondary display
indicates the AC voltage measurement.
2 Press for more than 1 second to exit this mode.
NOTE
If the rotary switch is at the “~ V” position, press to switch between the
dBV and the dBm measurements. The dBm or the dBV measurements can be
selected at the ACV position. The selection will be the reference for other
voltage measurements.