ASTRO AOMM-FHM2 Operating Manual page 20

page 20
The button is used to adjust the unit in which the optical power
is displayed. The power meter defaults to the unit of "dBm". Press
this button to shift to "dB" and "mW".
:
NOTE
DRAFT VERSION
absolute value of the meausred power value. If this power
value is less than 1 mW in the unit of "mW", the unit will be
shifted to "uW" automatically.
"dB" is the relative value of the measured power value. Firstly,
the user should set a reference value. Then, the current value
can be compared to the reference value. The formula is "dB"
value equals to "the reference value" minus "the current power
value in dBm".
The button can be used to set the reference value of the power
meter.
The reference value defaults to 0,00 dBm on the optical power
meter module. Long press the button for over 2 seconds and the
instrument will set the current optical power value as the reference.
Short press the key to read the current reference value. The instru-
ment will return to the testing state after two seconds without oper-
ation. If there's operation, the instrument will shift to the reference
editing state.
"dB" and "mW" are the unit representing the
Operating manual AOMM-FHM2 -
Operating the device
Version 11-2021A