:CHANnel:SKEW
Command Syntax
:CHANnelN:SKEW <delay>
Where N identifies a specific channel and must be selected from {1:8}{A|B|C|D}. For example, CHANnel3C.
Where <delay> is the delay in seconds and is a double.
Query Syntax
:CHANnelN:SKEW?
Description
For N1000-series plug-in modules (for example, N1045A), DCA-M modules (for example, N1094A/B), and an 86118A-H01 modules, applies hardware skew for the indicated remote sampling head. Hardware skew can also be applied to simulated waveforms. Skew effectively matches the electrical lengths of the two channels by adjusting the timing of the internal sampling. Enter a skew value in seconds for each channel. Applying skew can increase the time required for data acquisition. This command does not work for the channels of modules other than the above mentioned modules. To automatically deskew differential channels, use the :DIFF:DESKew command. To apply software skew to any module's channels, use the :CHANnel:TDELay command.
The module's RF inputs are very sensitive to ESD . Small RF connectors (for example, 1 mm and 1.85 mm RF connectors require special care.
The skew adjust differs from the Horizontal position control (:TIMebase:POSition), which changes the position all of the channels at the same time. Adjusting the skew does not affect the horizontal scale, vertical scale, and offset of the displayed channels.
Skew Non-Linearity. The skew value displayed on the Differential Skew control window is a rough approximation to the amount of skew being introduced into the measurement channel.For instance, setting the left channel skew to 100 ps will skew that channel by roughly100 ps. The actual amount that it moves may be more like 140 ps.
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.
Timebase Jitter. At its default skew setting (0 ps), the circuitry in the 86118A that skews differential signals has virtually no measurable impact on the jitter of the DCA, even if a precision timebase (86107A) is used. However, changing the skew to a value other than the default may affect the jitter of the DCA slightly.