Radix-4 butterfly LSI in direct-imaging Waseda radio interferometer for a Pulsar survey

Naoki Tanaka*, Tsuneaki Daishido, Hiroshi Takeuchi, Yukinori Akamine, Masaya Kuniyoshi, Taisei Suemitsu, Fumiyuki Fujii, Kentaro Gotoh, Tomoya Suzuki, Saori Mizuki, Keiju Mizuno, Koji Fukuoka, Masahiro Suzuki

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    3 Citations (Scopus)


    In the Nyquist rate direct-imaging interferometer at Waseda University, a radix-4 butterfly LSI has been developed for the spatial-temporal (2+1)D FFT processor to survey pulsars. In (2+1)D FFT, the first 2D FFT is a 2D directional finding spatial FFT processing for an 8×8 pixel image. The second 1D FFT is a 1D spectral finding temporal FFT processing for a 64ch frequency analysis in each 64 pixels. Since fewer multipliers are required in radix-4 FFT than in radix-2 FFT, we have implemented radix-4 algorithms in the present butterfly LSI. This implementation, using 512 radix-4 butterfly LSIs, could reduce the circuit size of the parallel and pipeline (2+1)D FFT processor. Additional functions, such as shift registers, digital filters and post-process sections, are also included in the LSI for a radio interferometric pulsar survey.

    Original languageEnglish
    Pages (from-to)447-455
    Number of pages9
    JournalPublications of the Astronomical Society of Japan
    Issue number3
    Publication statusPublished - 2000


    • Instrumentation: interferometers
    • Pulsars: general
    • Techniques: interferometric

    ASJC Scopus subject areas

    • Astronomy and Astrophysics
    • Space and Planetary Science


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