Resolution of Period Measurement with the PCI-6624Hardware: Counter/Timers (TIO)>>Devices>>PCI-6624, Counter/Timers (TIO)>>Devices>>PXI-6624
Problem: While performing a period measurement with the PCI-6624, the resolution appears to be 500 ns. The timebase is 20 MHz, so shouldn't the resolution be 50 ns? Solution: The PCI-6624 has a built-in digital filter functionality that has a default setting of 1 μs. Because of this, the filter clock signal changes every 500 ns and a change in the input signal will only be registered once every 500 ns. Therefore the resolution will be 500 ns. The available filter clock settings for the PCI-6624 are 1 μs, 5 μs, and a customizable filter clock can be used. Please see the Digital Filtering section of the TIO Series Help for more information. Note: This filter cannot be disabled on the NI 6624, as it is required for the proper functionality of the high voltage isolation circuitry. Related Links: Product Manuals: NI 6624 Product Manual Product Manuals: NI 6624 Specifications KnowledgeBase 38J9OSCH: Electrical Considerations for High Voltage I/O With the NI 6624 KnowledgeBase 35RHIHIO: Why Do I See an Incorrect Output on My PCI 6624 TIO Series Help Attachments:
Report Date: 09/01/2005 Last Updated: 04/10/2009 Document ID: 3P0COO88 |
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