This section provides more information regarding NI-TClk Manual Calibration and adjustment functions on NI Digitizers/Oscilloscopes. Skew adjustment is only part of Manual Calibration.
niScope Adjust Sample Clock Relative Delay.vi
This VI delays to the sample clock relative to the Reference clock. This is the VI that should be used to manually calibrate a NI-TClk session for all supported NI digitizers.
This VI is intended to only be used for NI-TClk Manual Calibration, and behavior outside of this use case in unspecified. This function can only adjust up to +/- 1 sample clock period per call, but the effect of multiple calls is cumulative.
“niScope Trigger Delay” on the niScope Trigger VI
Trigger delay is the amount of time that elapses between when a trigger occurs and when the digitizer actually triggers.
See High-Speed Digitizers Help >> Fundamentals >> Triggering >> Trigger Parameters >> Trigger Delay
When using trigger delay, no trigger or synchronization signals are physically altered or delayed, therefore it is not possible to use this property to create a trigger delay generator.
NI-TClk Sample Clock Delay Property
This property is for setting a delay to a device's sample clock, additional to the NI-TClk synchronization. This property needs to be set before calling the niTClk Syncronize VI. This property is useful if you want to have the sample clocks synchronized, but have a constant delay/offset/phase relationship. This property can only adjust sample clocks within +/- 1 sample clock; NI-TClk should have adjusted the sample clocks to within this window.
For example: To implement TIS (Time Interleaved Sampling) between two digitizers, use this property to configure the two devices have a 180 deg phase relationship (1/2 of period). They would be synchronized using NI-TClk, and then an 180deg phase offset would be applied.
Note: This property can also be used for Manual Skew Adjustment for PXIe-5160/5162 devices.
Property: niScope Oscillator Phase DAC Value
This property is adjusted indirectly through the use of "niScope Adjust Sample Clock Relative Delay.vi", and is the raw value used to adjust the Sample clock relative to the Reference clock.
The intended use case for this property is to allow for repeatable synchronization, when used as outlined in the NI-TClk Manual Calibration steps above. For NI digitizers when this property is set, the synchronization process initiated by the “niTClk Synchronize” VI, will rely on this property for the fine clock adjustment, which leads to reduced time to perform the NI-TClk synchronization.
Note: This property can also be used for Manual Skew Adjustment for PXIe-5185/5186 devices. The value written to the devices will remain valid until Self-Calibration is initiated, any changes to the Reference Clock or External Clock are made, the device is reset, or after reboot.