Tektronix OM4006D, Руководство пользователя, Страница: 158 / 205

Appendix E: Equivalent-Time (ET) oscilloscope operation
8. Once this is done get equal signal on both polarizations by re-enabling all
four channels:
9. The last step is to set the middle slider to achieve minimum signal in the
Y-polarization. Since the input is a single-pol signal at this point, nothing
should be in the Y constellation or eyes except for noise.
10. Display the Y-I or Y-Q eye diagrams and Y-Constellation to see the signal
going into the wrong polarization. This should just be noise when the middle
slider is set properly.
11. The delay calibration is done if there is only noise in eye plots except the X-I
and only noise in the Y-constellation for a single-pol BPSK signal.
12. Save the setup on the oscilloscope using the File > Save Setup As command
to overwrite the default.stp fi le in My Documents\TekScope\UI\default.stp.
Figure 19: When adjusting the middle slider, watch the Y-Eye and Y-Const to
minimize the signal in the Y-polarization
134 OM4000D Series Coherent Lightwave Signal Analyzer