Picotest M3500A User Manual page 92

Remote Interface Operation
Use the following commands from your PC terminal to make the dB
measurement:
CALCulate:FUNCtion DB
CALCulate:STATe {OFF|ON}
CALCulate:STATe?
CALCulate:DB:REFerence {<value>|MINimum|MAXimum}
B. dBm
Definition
With dBm selected, a voltage measurement is displayed as the level of
power, relative to 1 milliwatt, dissipated through a reference resistance.
The reference resistance is adjustable in M3500A. The calculation of dBm
is defined as below:
Note: V is the input signal voltage.
※
in
Note: Change of reference resistance will not affect the stored relative
※
reference value.
The Zref is adjustable with a range from 50
value is 600
The selected reference value by you is stored in a volatile memory
and will be cleared after the multimeter has been power-off.
This feature is available for DCV and ACV only.
How to set the reference resistance
You can set the reference resistance either through the front panel
operation or the remote interface operation.
Front Panel Operation
Press CONFIG + SHIFT + MIN/MAX, then use
through the digits and
a desired value. Press ENTER to set the value. The locations of the
buttons are shown with red rectangle frames in Figure 4-23.

2
V

= ×
dB 10 log
in
m Z

.
and to increase or decrease the numbers to
△ ▽


1 / mW

ref
Z is the reference resistance.
ref
to 8000
and
◁
92 92 92 92
. The default
to move
▷