Instructions

3
.
Functions and Operations
26
 dB Function
dB represents the relative value which is used in the relative operation of dBm value.
When enabled, the multimeter calculates the dBm value of the reading and subtracts the
preset dB from this value and then displays the result:
dB = 10 x Log
10
( reading
2
/ reference resistance / 1 mW) - dB preset
Press the Rel R softkey to select the reference resistance. The value may be 50(default),
75, 93, 110, 124, 125, 135, 150, 250, 300, 500, 600, 800, 900, 1000, 1200, or 8000 Ω.
Press the dB Rel softkey to select the relative value. The relative value must be from -120
to +120 dBm (default 0).
Relative Value
When the relative operation is turned on, the reading displayed on the screen in relative
operation is the difference between measured and preset values. The value is specific to
the present function and will persist even if you leave this function and return to it later.
Reading = Measured value – Preset value
In the measurement function menu, press the Rel softkey to turn on or off the relative
operation. When on, the measured value is stored as a reference value.