Operating Basics
60
P7380SMA 8 GHz Differential Probe Instruction Manual
Deskewing Probes
You can measure the skew between two P7380SMA probes by using
a Tektronix 80E04 Sampling Head configured for a TDR output.
Because the skew of the P7380SMA probe inputs is less than 1 ps,
two P7380SMA probes can be deskewed using single-ended drive
signals from a dual-channel TDR source. The TDR output provides a
pair of time-aligned pulses that you can use to compare probe
response times, and if necessary, adjust them to match (deskew).
Figure 26 on page 61 shows a setup for checking and deskewing two
probes. Deskewing aligns the time delay of the signal path through
the oscilloscope channel and probe connected to that channel, to the
time delay of other channel/probe pairs of the oscilloscope.
If you need to deskew more than two probes, keep one deskewed
probe connected to the sampling head as a reference (after
deskewing two probes), and deskew additional probes to that probe.
In this procedure, Channel 1 is used as the reference channel.
1.
Set up the equipment as shown in Figure 26 and let it warm up
for 20 minutes, but don’t make any connections to the TDR
outputs yet.
2.
Do a system compensation for the TDR module, and then verify
the skew of the two outputs with the TDR outputs open, using a
common-mode TDR drive.
Skew between the two outputs can be compensated with the
deskew control. Refer to your sampling head or oscilloscope
manual for instructions.
3.
Attach the probes to the TDR outputs as shown in Figure 26 on
page 61.