Fluke 289 User Manual page 34

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Users Manual
To select another reference value, press the softkey labeled Ref
to display a message box with the current reference value.
Pressing 7 or 8, scrolls through the nine predefined references:
4, 8, 16, 25, 32, 50, 75, 600, and 1000. Set the reference by
pressing the softkey labeled OK. To add a custom reference
impedance, see the "Setting a Custom dBm Reference" section
later in this manual.
A dBV measurement uses a 1 volt reference voltage to compare
the present measurement against. The difference between the
two ac signals is displayed as a dBV value. The reference
impedance setting is not part of a dBV measurement.
To make a dBV measurement, position the rotary switch to V or
T and place the Meter leads on the voltage to be measured.
Next, press the softkey labeled Menu. Move the menu selector
to the menu item labeled dBV and press the softkey labeled
dBV. The Meter displays the voltage in dBV.
To exit the dBV or dBm function, press the softkey labeled Menu
followed by the softkey labeled dBV or dBm, respectively.
Selecting one of the other modifiers such as ms, %, or CF also
cancels dBV or dBm.
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