:DIFF:DESkew
Command Syntax
:DIFF{1:8}{A|C}:DESkew
Where the required specifier {1:8}{A|C} identifies the differential channel by its module slot and channel letter. For example, the differential waveform of channels 1A and 1B would be identified as :DIFF1A.
The channel specifier will fail if it does not include a slot number. If instead the suffix's channel letter is missing, the command defaults to letter A. As a result, the best practice is to always explicitly specify the channel by including both the module slot number and channel letter.
Description
For N1000-series plug-in modules (for example, N1045A), DCA-M modules (for example, N1094A/B), and an 86118A-H01 modules, starts an Auto Differential Deskew which removes all skew between differential inputs of the modules, regardless of the source of the skew. The skew could be introduced by fixtures, the device-unter-test, or the transmitter. Use this feature if you want to remove the skew and you are not interested in measuring the skew. You can also use this command to apply simulated hardware skew to simulated channels. Hardware skew is applied to both channels. To manually apply hardware skew to the individual channels, use the :CHANnel:SKEW command.
The :DIFF:DESkew command is not designed to correct for skew that has been introduced by external hardware between two waveforms; use the :TIMebase:DESKew:FIXTure command instead.
An identical signal must be applied to both input channels before performing an Auto Deskew.
Avoid bending the remote-head cables after the deskew is performed. The cables connecting the 86118A remote heads to the plug-in module contain a high-frequency sampling strobe signal. The cables are designed to minimize the change in phase of the strobe signal as the cable is bent. However, bending either cable will change the cable's phase by several picoseconds, thereby skewing that channel relative to the other channel, as seen on the DCA display. Before performing a deskew on the channels, it is best to position the remote sampling heads as they will be used during the measurement.
Requires FlexDCA revision A.02.00 and above.
Example Command
:DIFF2A:DESkew