Tektronix OM4006D, User Manual

Page: 94 / 205

Taking measurements
Table 14: Multicarrier spectrum controls
Item Description
Freq/Div Click the narrow spectrum icon (narrower spectrum, more GHz/Div)
or wide spectrum icon (wider spectrum, less GHz/Div) to change the
horizontal frequency axis scale. Units are selectable via the drop-down
menu but also change automatically when a change is made to the
Absolute/Relative/Autocenter choices.
Cent Freq Click the left arrow (spectrum left, higher center frequency) or right arrow
(spectrum right, lower center frequency) to change the center frequency
value one full division at a time or type in the value directly. Units are
selectable via the drop-down menu but also change automatically when a
change is made to the Absolute/Relative/Autocenter choices.
Ref dBW Use the +/- buttons to increase or decrease the power in dBW
corresponding to the top of the plot.
dB/Div Click the tall spectrum icon (taller spectrum, less dB/Div) or short spectrum
icon (shorter spectrum, more dB/Div) to change the vertical axis scale.
Absolute/
Relative Click to toggle between Absolute and Relative (relative to current
Reference Laser frequency) frequency axis modes. A 194 THz signal with
a 193.999 THz Reference Laser frequency will be displayed at 194THz in
Absolute mode and at 1 GHz in Relative mode.
Autocenter
Click to turn Autocenter on or off. With Autocenter on, all channels will be
shifted to zero Hz center frequency to facilitate visual comparison.
Understanding the multicarrier spectrum plot.
Figure 8: Multicarrier spectrum plot
70 OM4000D Series Coherent Lightwave Signal Analyzer