An optimization of the FPGA/NIOS adaptive FIR filter using linear prediction to reduce narrow band RFI for the next generation ground-based ultra-high energy cosmic-ray experiment

Zbigniew Szadkowski*, E. D. Fraenkel, Dariusz Glas, Remigiusz Legumina

*Corresponding author for this work

    Research output: Contribution to journalArticleAcademicpeer-review

    11 Citations (Scopus)


    The electromagnetic part of an extensive air shower developing in the atmosphere provides significant information complementary to that obtained by water Cherenkov detectors which are predominantly sensitive to the muonic content of an air shower at ground. The emissions can be observed in the frequency band between 10 and 100 MHz. However, this frequency range is significantly contaminated by narrow-band RFI and other human-made distortions. The Auger Engineering Radio Array currently suppresses the RFI by multiple time-to-frequency domain conversions using an FFT procedure as well as by a set of manually chosen BR notch filters in the time-domain. An alternative approach developed in this paper is an adaptive FIR filter based on linear prediction (LP). The coefficients for the linear predictor are dynamically refreshed and calculated in the virtual NIOS processor. The radio detector is an autonomous system installed on the Argentinean pampas and supplied from a solar panel. Powerful calculation capacity inside the FPGA is a factor. Power consumption versus the degree of effectiveness of the calculation inside the FPGA is a figure of merit to be minimized. Results show that the RH contamination can be significantly suppressed by the LP FIR filter for 64 or less stages. (C) 2013 Elsevier B.V. All rights reserved.

    Original languageEnglish
    Pages (from-to)535-539
    Number of pages5
    JournalNuclear instruments & methods in physics research section a-Accelerators spectrometers detectors and associated equipment
    Publication statusPublished - 21-Dec-2013
    Event13th Vienna Conference on Instrumentation - , Austria
    Duration: 11-Feb-201315-Feb-2013


    • Linear predictor
    • FIR
    • RFI filtering
    • Geo-synchrotron radiation
    • Radio detection
    • Levinson recursion

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