Summer of LabVIEW The Sunny Side of System Design

Transcription

1 Summer of LabVIEW The Sunny Side of System Design 30th June - 18th July 1

2 Real Time Spectrum Monitoring and Signal Intelligence Abhay Samant Section Manager RF and PXI Aerospace and Defence National Instruments

3 What Is Spectrum Monitoring? RF Measurements & Signal Processing that shows how frequency spectrum is being used. Spectrum Monitoring always Signal Intelligence 3

4 Who Does Spectrum Monitoring? Government: Ensure spectrum users obey licensing to minimize interference amongst users. Commercial Spectrum Owners: Monitor operation of systems and troubleshoot interference problems. Defense Intelligence: Characterize the radio frequency environment to support their missions. 4

5 Why do we need Spectrum Monitoring Limited Spectrum Crowded Spectrum Interference 5

6 Modern Challenges in RF Applications RADAR Spectrum Monitoring Cellular/Wireless Electronic Warfare Short duration, nonperiodic pulses. Weak signals in the presence of strong signals. Overlapping, crowded bands. Weak signals in the presence of strong signals. Wideband bursted transmissions Complex modulation algorithms Short duration pulses Wideband bursted transmissions Complex modulation algorithms Weak/Strong signals 6

7 Typical Measurement for Spectrum Monitoring Receiver Over the air Measurement Detection of weak signal of interest in presence of strong interferers 7

8 History of RF Analyzers Early 1960s Around 1967 RF RF ADC CPU Swept-Tuned VSA (Not Real Time) 8

9 Swept Tuned Spectrum Analyzers RF Signal is missed! dbm SAs return Power vs. Freq data SAs have large dynamic range SAs sweep an LO across frequency segments ƒ 1 ƒ 2 ƒ 3 f 9 SAs have narrow BWs and are analog As the LO sweeps, SAs could miss a transient signal

10 FFT Based Vector Signal Analyzers RF ADC CPU Signal is missed during CPU processing! dbm VSA Acquire Process VSAs return Mag & Phase vs. Freq data VSAs have a digital back-end VSAs have large dynamic range VSAs acquire a wide bandwidth As VSAs process acquired data, it could miss a transient signal ƒ 1 ƒ 2 ƒ 3 f 10

11 History of RF Analyzers Early 1960s Around 1967 RF RF ADC CPU Mid 2000s Swept-Tuned VSA (Not Real Time) RF ADC FPGA RTSA (Real-Time) 11

12 Real Time Spectrum Analyzers RF ADC FPGA Signal is not missed due to Real-Time processing! dbm RTSA Process & Acquire RTSAs return Mag & Phase vs. Freq data - new types of displays RTSAs have a digital back-end with a co-processor RTSAs have large dynamic range RTSAs acquire a wide bandwidth RTSAs acquire and process data in Real-Time specify 100% POI ƒ 1 ƒ 2 ƒ 3 f 12

13 RTSA - Gap Free Conversion Measure Power Traditional Tune Tune Tune Tune Tune Tune Tune Vector Acquire Process Acquire Process Acquire Real-time Acquire Acquire Acquire Acquire Acquire Acquire Process Process Process Process Process Time FPGA 13

14 Probability of Intercept (POI) and Gap-Free Processing 100% POI - how long, in seconds, a signal must be present in order for an RTSA to guarantee that the signal will be detected 100% of the time within a certain amplitude accuracy. IQ Rate fs (S/s) = 1 GS/s FFT Overlap Lgap (S) = S FFT Length Lfft (S) = 1024 S t min t min FFT 0 Gap FFT 1 Gap FFT 2 FFT 0 FFT 2 FFT 1 FFT 3 t fft t gap VSA sequential FFTs 0% overlap RTSA 50% overlap FFTs 14

15 Comparison Product Real-Time Bandwidth Maximum Frequency 100% POI NI PXIe-5668R+7976R 765 MHz 26.5 GHz 1.5 µs Keysight UXA 510 MHz 26.5 GHz 3.51 µs R&S FSW 160 MHz 67 GHz 1.87 µs Tektronix RSA5000/RSA MHz 26.5 GHz 3.7 µs 15

16 Persistence Display 16

17 Persistence Display z-axis: brighter colors represent frequencies and powers where signals are more present Adjusts Accentuates Applies the level a decay at the which less effect frequent the to image the events image clips Power (dbm) Frequency (Hz) 17

18 Spectrogram Display 18

19 Spectrogram Display A spectrogram display presents spectral activity over time - each line is the result of averaging a number of spectrums. z-axis: amplitude (dbm) Configure the max/min pwr brighter Amount Peak colors or of are averages higher for per pwr each a levels line Time (s) Frequency (Hz) 19

20 Frequency Mask Trigger Mask Trigger All-Time Signal Peak 20

21 Demonstration: Real-Time Spectrum Analysis Gapless persistence, spectrogram, and trace statistics (max hold, min hold, average) calculated on FPGA Process up to 2 M FFTs/s using overlapped, windowed FFTs Real-time frequency mask triggering 100% probability of intercept (POI) minimum duration options: 1 µs or >15 µs Source available upon request 21

22 NI RTSA P2P and Data Throughput PXIe-5668R VSA + PXIe-7976R FlexRIO in PXIe-1085 P2P - IQ data from VSA to FlexRIO bypasses host Potentially add more FlexRIOs for greater processing power DMA - Spectral data from FlexRIO to Host CPU for viewing PXIe-7976R FlexRIO PXIe-5668R VSA Spectral IQ data Data at at <100 MB/s 3 GB/s via DMA via P2P 22

23 FPGA Technology What is an FPGA? Software defined hardware No operating system is needed for execution of logic Dedicated logic in silicon for highest reliability I/O Blocks FPGA Logic Inline signal processing with minimal latency High-speed and deterministic control 23

24 NI RTSA Block Diagram FlexRIO FPGA Module VSA IQ Data P2P Persistence To Host Spectral Data Spectrogram To Host To Host Frequency Mask + Trace Math Triggers 24

25 Out-of-the-Box Functionality + FPGA Enhancements I/O Additional DSP P2P and additional co-processing or record to disk Custom displays like Persistence and Spectrograms Customer triggering and routing Application-Specific Enhancement 25

26 RTSA Hardware Options 100% POI Sample Rate PXIe-5644R/45R 12.8 µs 120 MS/s PXIe-5663/65/ µs 150 MS/s PXIe-5646R 6.1 µs 250 MS/s NI PXIe-5644R/45R/46R VST PXIe-5668R 1.5 µs 1G S/s NI PXIe-5668R VSA NI PXIe-7976R FlexRIO NI PXIe-5663/65/67 VSA 26

27 IF Digitizer with User-Programmable FPGA NI PXIe-5624R High sample rate: 2 GS/s High dynamic range: 12-Bit Analog bandwidth: 2 GHz High speed bus: Gen. 2 x8 PCI Express (up to 3.2 GB/s) User-programmable: Xilinx Kintex-7 FPGA Application Areas IF-Digitizing of signals from Downconverters / Mixers Direct RF acquisition 27

28 NI RTSA Value Proposition NI RTSA Other RTSAs BW 765 MHz 500 MHz POI 1.5 us 2 us Dynamic Range 119 dbc 119 dbc Record to Disk Yes, full BW Some have it, but not full BW IQ Data Yes No Open FPGA* Yes No Multi-channel Yes No Modularity Yes No *Custom triggering, channelization, data throughput control 28

29 NI Spectrum Monitoring Advanced Features FPGA/DSP Measurements & Calculations Real time spectrum analyzer Real time processing for DDC channelization Raw IQ Data, Spectrum & Mask Violations GPS Position, Timestamp & Synchronization Modulation Toolkits for RF Standards Multi channel with phase coherence and time synchronization 12 TB RAID Storage (>8 hrs continuous) Compatible with 3 rd party Post-Processing Software 29

30 RTSA Resources The example, NI RTSA Host Example for the NI 7976R is distributed using VI Package Manager. Please view this webcast for more information 30

31 Any Questions? Next Sessions 12:45 13:45 13:45 14:30 Automated Test and RF Increase Test Flexibility by Standardizing on a Software- Defined, Modular Hardware Architecture Lunch and Exhibition Aerospace and Defence Multi-Channel Phase Coherent Measurements 31