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2-17
Using the Multi-Wavelength Meter
Defining Laser-Line Peaks
adjacent signal. The peak excursion’s default value is 15 dB. Any laser line that
rises by 15 dB and then falls by 15 dB passes the rule. You can set the peak
excursion value from 1 to 30 dB.
Examples of valid
and invalid signals
In the following figure, three laser lines are identified: responses
➀
,
➂
, and
➃
.
Response
➁
is not identified because it is below the peak threshold. The por-
tion of each signal that is within the peak excursion limits is shown in bold
lines.
Because of the peak excursion rule, responses
➃
and
➄
are identified as one
laser line—the minimum point between
➃
and
➄
does not drop to the peak
excursion limit. This response has the highest power shown which is peak
➃
.
Whenever the peak threshold limit or peak excursion value is changed, the
new limits are applied to the current displayed measurements even if the
instrument is in the
Single
measurement mode.
The following figure shows the same laser lines as the previous figure, but the
peak-excursion value has been changed from 15 to 3 dB. Four laser lines are
now identified with responses
➃
and
➄
identified as two distinct laser lines.