HP 34401A, User Manual

Page: 41 / 236

To Make dB Measurements
Each dB measurement is the difference between the input signal and a
stored relative value, with both values converted to dBm.
dB = reading in dBm – relative value in dBm
•
Select
DC V
or
AC V
.
•
The first reading taken after you enable dB measurements is
converted to dBm and is stored as the relative value in the
dB Relative Register. Any previously stored value is replaced
with the new value.
•
After enabling dB operations, you can edit the relative value by
pressing
Shift >
(Menu Recall). This takes you to the “
dB REL
”
command in the
MATH MENU
( only if dB is enabled) . Go down to
the “parameter” level, and then edit the value displayed.
•
The register is cleared when you change functions, turn dB off,
turn off the power, or perform a remote interface reset.
Enables dB operation;
Press again to disable. Math annunciator is on when
dB operation is enabled.
To read / edit the dB relative value, use the MATH menu.
Chapter 2 Front-Panel Menu Operation
To Make dB Measurements
40