PXI-5661 Stream to Disk Using Win32 File IO and NI-RFSA
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This example demonstrates using continuous acquisition to fetch IQ data from the PXI-5661 Vector Signal Analyzer while continuously streaming the data to a binary file using the Win32 File I/O VIs. The vertical range and the IQ rate of the NI Vector Signal Analyzer (VSA) are configured using the NI-RFSA VIs. The VSA is configured to run continuously with the niRFSA Configure Number of Samples.vi, and data is continuously fetched from the onboard memory of the device within the producer loop using the niRFSA Fetch IQ.vi. Benchmarks with the recommended hardware below have been at 100MB/s of data streaming to disk. The producer loop continuously fetches data from onboard memory into the LabVIEW memory using DMA transfers. This data is placed into a queue in order to efficiently transfer the data to a parallel consumer loop where it is written file. If the sampling rate is low, the computer can fetch all the data from the VSA, so data is never overwritten. However, at faster sampling rates, the computer will not be able to fetch the data before it is overwritten by new data. This results in the "data overwritten" error. The consumer loop continuously empties data from the queue and writes data to disk using the Win32 Write File.vi. The file is opened using the Win32 Open File.vi, which disables Windows caching during the write process, resulting in increased performance. However when Windows caching is disabled, data must be written to file in a multiple of the sector size of the disk (typically 512 bytes).
Downloads
Filename: ni-rfsa.zip
Requirements: View
NI Recommended Hardware:
- PXI 5661
- PXI 8105/8106 controller
- Addonics eSATA 4-drive RAID (ST5X1PM-4)
- ExpressCard34 to eSATA Adapter (ADEXC34R5-2E)
Software:
- NI-RFSA 2.0.1 or above
- LabVIEW 8.0 or above
Recommended Input Signal: 100 MHz, 0dBm, sine wave
Requirements
Filename: ni-rfsa.zip
Software Requirements
Application Software: LabVIEW Professional Development System 8.0
Hardware Requirements
Hardware Group: RF
Hardware Model: PXI-5661
Driver: NI-RFSA 2.0.1
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