HP 34401A, User Manual

Page: 69 / 236

•
Remote Interface Operation : You can use the following commands to
make dB measurements. Math must be enabled before you can store a
value to the Relative Register.
CALCulate:FUNCtion DB
CALCulate:STATe {OFF|ON}
CALCulate:DB:REFerence {<
value
>|MINimum|MAXimum}
dBm Measurements
The dBm operation calculates the power delivered to a resistance
referenced to 1 milliwatt.
dBm = 10
×
Log
10
( reading
2
/
reference resistance
/
1 mW )
Applies to dc voltage and ac voltage measurements only.
•
You can choose from 17 different reference resistance values.
The factory setting for the reference resistance is 600
Ω
.
The choices are: 50, 75, 93, 110, 124, 125, 135, 150, 250, 300, 500,
600 , 800, 900, 1000, 1200, or 8000 ohms.
•
The reference resistance is stored in non-volatile memory, and does not
change when power has been off or after a remote interface reset.
•
Front-Panel Operation : After enabling dBm, you can select a new
reference resistance by pressing
Shift >
(Menu Recall). Turning
on the menu does not disable the dBm operation; the multimeter
will resume taking measurements when you turn off the menu.
4: dBm REF R (MATH MENU)
See also “To Make dBm Measurements,” on page 41.
•
Remote Interface Operation : You can use the following commands to
make dBm measurements.
CALCulate:FUNCtion DBM
CALCulate:STATe {OFF|ON}
CALCulate:DBM:REFerence {<
value >|MINimum|MAXimum}
Chapter 3 Features and Functions
Math Operations
68