Can I Synchronize Different Types of DSA Devices at Different Rates?
Hardware: Modular Instruments>>Dynamic Signal Acquisition and Analysis (DSA)
Problem: I have a 4462 and a 4472. I would like these two devices to be synchronized together but to acquire data at different rates. Is this possible?
Solution: The short answer is no, unless your devices are PXI and you also have a PXI-6652 or PXI-6653.
To synchronize multiple DSA devices together at different rates they must be the same device. For instance you can share the Sample Clock Timebase between multiple PXI-4462 devices and they can all sample at different rates. Please note that there are limitations to what sample rates you can select. For more information on this subject please see the NI-DSA help linked at the end of this KB.
NI DSA Help > DSA Device Concepts > Synchronization > Heterogeneous Synchronization
You can synchronize a 4462 and a 4472 together, but they can acquire data at the same rate only. The one exception to this rule is if the two devices are PXI and you also have a PXI-6652 or PXI-6653. These timing and synchronization modules have DDS or Direct Digital Synthesis clock generation. You can use this feature to generate up to three different oversample clocks needed by the DSA devices. These clocks can be routed to the PXI_STAR or PXI_TRIG lines in the PXI chassis and then to the Sample Clock Timebase on each device. Two of the clocks are a divided version of the main DDS clock, so they will all be related by a power of two. The diagram below is part of the block diagram found on page 27 of the NI PXI-665x User Manual.
Related Links: NI Dynamic Signal Acquisition User ManualNI PXI-665x User Manual
Attachments: 
- 665x_Block.JPG
Report Date: 11/09/2006
Last Updated: 01/28/2008
Document ID: 438CR17E
- 665x_Block.JPG
