Tektronix P7313SMA, Technical Reference

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Operating Basics
Adjusting Cable Skew
If you want to minimize the skew introduced by cable pairs other than those supplied with the probe, you can use a pair of
phase adjusters to bring the skew to within 1 ps. (See page 48,
Optional Accessories .) The phase adjusters have male and
female SMA connectors to simplify connections to your measurement system.
You must add a phase adjuster on each cable to balance the delay and insertion loss introduced by the phase adjuster. You
only adjust (add delay to) the phase adjuster on the cable with the shorter delay.
The adjustment range of the phase adjusters on the Optional Accessories list is 25 ps, so if you use cable pairs other than
those supplied with the probe, the initial delay mismatch should be less than 25 ps.
1. Connect the phase adjusters to the cables.
2. On the cable with the longer delay, loosen the phase adjuster locking nuts, set the phase adjuster to minimum delay
(shortest length), and secure the locking nuts. (See Figure 12.)
Figure 12: Using the phase adjuster
3. Loosen the locking nuts on the adjuster that is connected to the other cable (with the shorter delay).
4. While observing the oscilloscope display, turn the collar on the phase adjuster counterclockwise to increase the delay.
5. When the displayed skew on screen is less than 1 ps, tighten the locking nuts.
6. Con fi rm that the skew is acceptable after you tighten the locking nuts, as the adjustment may change slightly during
tightening.
7. Disconnect the cables from the sampling head, and connect them to the P7313SMA probe head.
P7313SMA Technical Reference 19