Tektronix CSA8000 Series, Service Manual

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Optical Sampling Modules
CSA8000 & TDS8000 Instruments and Sampling Modules
4–109
7. Zoom into the 50% crossing point of the first rising edge on the C3 clock
signal until the Horizontal SCALE is 10 ps/div and the Vertical SCALE is
10 mV/div. See Figure 4–32
NOTE
. You can most easily zoom in on the 50% crossing point by click dragging
a rectangle around this edge (using the mouse), and then using the SCALE and
FINE control knobs to adjust the settings to 10 mV/div and 10 ps/div.
8. Check that the RMS jitter measurement for C3 is less than 8 ps RMS.
9. Repeat this procedure from step 1 to check the recovered clock timing jitter
for each of the clock recovery rates of the optical sampling module you are
testing. See Table 4–10.
End of Procedure
Figure 4–31: Example of the display when the clock signal from the 80C0X-CR
Optical Sampling Module is synchronous with the data rate input from the pulse
pattern generator. Note the stable clock signal waveform. Compare this with
Figure 4–30, in which the clock signal is not synchronized.