Digital spectrometers for the Nobeyama 45-m telescope

Kazuo Sorai; Kazuyoshi Sunada; Sachiko Kawabe Okumura; Iwasa Tetsuro; Atsushi Tanaka; Kazuhito Natori; Hirofumi Onuki

doi:10.1117/12.390466

3 July 2000 Digital spectrometers for the Nobeyama 45-m telescope

Kazuo Sorai, Kazuyoshi Sunada, Sachiko Kawabe Okumura, Iwasa Tetsuro, Atsushi Tanaka, Kazuhito Natori, Hirofumi Onuki

Proceedings Volume 4015, Radio Telescopes; (2000) https://doi.org/10.1117/12.390466
Event: Astronomical Telescopes and Instrumentation, 2000, Munich, Germany

Abstract

New digital spectrometers for the 25-BEam Array Receiver System (BEARS) of the Nobeyama 45-m telescope are described. A commercial digital oscilloscope is used as a digitizer. The digitizer samples analogue data with 2 bits (4 levels). Data of 512 MHz bandwidth are processed for four beams at the same time. The data-formatting unit demultiplexes 2 bits 8 data in parallel to 32 parallels and sends outputs to LSIs. General purpose LSIs for autocorrelation read the digital data with a clock rate of 32 MHz. Thirty-two LSIs of 32 lags connected in cascades calculate 1024-lag autocorrelation, and output a 1024-channel power spectrum of 512 MHz bandwidth. The bandwidth of 32 MHz is achieved by picking up the data in a rate of 1/16 in the front part of the autocorrelator module. The total performances have been demonstrated by long-term integration of noise signals from receivers and observations of the Galactic star-forming region W51 in CO line.

Citation Download Citation

Kazuo Sorai, Kazuyoshi Sunada, Sachiko Kawabe Okumura, Iwasa Tetsuro, Atsushi Tanaka, Kazuhito Natori, and Hirofumi Onuki "Digital spectrometers for the Nobeyama 45-m telescope", Proc. SPIE 4015, Radio Telescopes, (3 July 2000); https://doi.org/10.1117/12.390466

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