Teledyne LeCroy LabMaster 9Zi-A - Manual (Page 128)

LabMaster 9 Zi-A
120 922157-00 Rev A
LabMaster De-Skew Calibration
The ChannelSync™ architecture in LabMaster modular oscilloscope systems
utilizes a single 10 GHz distributed clock for all acquisition modules. This
provides precise timing alignment and timing accuracy between all
channels in all acquisition modules as found in a single, conventional
oscilloscope package. However, to ensure that the static skew of all
connecting cables is accounted for, a calibration is required for the most
accurate results.
De-Skew calibration eliminates:

Static skew due to minor differences in length of PCIe
interconnection cables. LabMaster modular oscilloscopes may
consist of multiple acquisition modules. These multiple modules
need to deskewed with respect to each other to account for
connection cable propagation delay (static skew). This propagation
delay is normally 100-200 ps and is a result of the very small
differences in length between the PCIe cables used for connections
on your particular LabMaster setup.

Minor static skew differences between channels and gain settings in
a single acquisition module.

The small amount of static skew remaining after the factory
hardware deskew. At the factory, channels in each Acquisition
Module are deskewed in hardware to within approximately 2 ps at
20 GHz. This can vary slightly over varying gain ranges (V/div
settings) on each channel. Depending on the timing accuracy
desired for your measurements and the bandwidth of your
acquisition module, you may need to correct for this.

Static skew introduced by probe and cable connections. With probes
and cables connected to the acquisition module, additional static
skew will be introduced. When these devices are attached, deskew
signals must be respectively deskewed to each other is again
required to eliminate the propagation delay of the signal due to
these items being added to the signal path.