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decibel unit in correspondence to a relative reference value. The
calculation of dB is listed below:
Or
dB = (Input signal in dBm) – (relative value in dBm)
※
NOTE: The
in
V
is
the input signal and the
ref
V
is the relative reference.
The dB measurement is applied to DC and AC voltage only. The relative
value is adjustable and is stored in a volatile memory. The range for the
relative value is between 0
dBm and
200 dBm, and the default value is
0 dBm
.
How to use dB feature
You can either manually select a number for the relative reference or let
the multimeter
take the first reading
(0 dB) as the relative reference.
Front Panel Operation (to set the relative reference)
1.
Select a measurement function by pressing DCV or ACV button.
2.
Do the procedure SHIFT + NULL > dB > ENTER > dB REL to access
the setting.
3.
Use
◁
and
▷
to move through the digits and
△
and
▽
buttons to
increase or decrease the numbers to your desired value. Press
ENTER to set the value.
4.
Press ENTER on “RUN” to start measurement.
※
Note: To disable the dB function, you always need to go to Math
submenu and select “OFF” or press other measurement buttons. The
“MATH” annunciator should not be lit when disabled.
Remote Interface Operation
Use the following commands from your PC terminal to make the dB
measurement:
)
log(
20
Vref
V
dB
in
×
=
