EXFO IQS-1600 High-Speed Power Meter for IQS-500/600 - Manual (Page 32)

Setting Up Your High Speed Power Meter
24 IQS-1600
Setting Channel Display(IQS-1620, IQS-1640)
Since operations between channels cannot be made with any type of
measurement unit, the second channel and the operator can be selected
according to the unit of the first channel as described in the following table.
Note: Since a virtual channel consists of a mathematical operation using two
optical channels, the only parameter that can be set for a virtual channel is
its name.
First
Channel Unit
Second
Channel Unit
Virtual Channel Unit and
Allowed Operators
dBm dBm dB (operator −)
dBm dB dBm (operators + and −)
dB dBm dBm (operator +)
dB dB dB (operators + and −)
W W W/W (operator /)
W W/W W (operators * and /)
W/W W W (operator *)
W/W W/W W/W (operators * and /)