EXFO IQS-1600 High-Speed Power Meter for IQS-500/600 - Manual (Page 47)

Preparing Your High Speed Power Meter for a Test
High Speed Power Meter 39
Nulling Offsets
To perform an offset nulling on one channel:
1. Install the protective cap over the detector port.
2. If necessary, select the desired channel (on a multichannel high-speed
power meter).
To set the channel, see Selecting a Channel (IQS-1620, IQS-1640) on
page 21.
Offset nulling values are applied to the channel until a new nulling is
performed.
3. Under Channel, click the Nulling button. A message prompts you to
ensure that the detector cap is properly installed.
4. Select OK to perform the offset nulling, or Cancel to exit.
A red message appears beneath the power value of the channel for
which you are performing a nulling.
If you are using a multichannel power meter, you will notice that the
other channels will stop reading power while nulling is in progress.