A broadband FFT spectrometer for radio and millimeter astronomy

¹ Institute of Astronomy, ETH, 8092 Zurich, Switzerland e-mail: benz@astro.phys.ethz.ch
² Acqiris SA, 1228 Plan-les-Ouates, Switzerland
³ University of Applied Sciences Solothurn, Nordwestschweiz, Switzerland
⁴ ZMA, Center for Microelectronics, University of Applied Sciences Aargau, Nordwestschweiz, Switzerland

Received: 3 June 2005
Accepted: 4 July 2005

Abstract

The core architecture, tests in the lab and first results of a Fast Fourier Transform (FFT) spectrometer are described. It is based on a commercially available fast digital sampler (AC240) with an on-board Field Programmable Gate Array (FPGA). The spectrometer works continuously and has a remarkable total bandwidth of 1 GHz, resolved into 16 384 channels. The data is sampled with 8 bits, yielding a dynamic range of 48 dB. An Allan time of more than 2000 s and an SFDR of 37 dB were measured. First light observations with the KOSMA telescope show a perfect spectrum without internal or external spurious signals.