DIGITAL IMPLEMENTATION OF A ROBUST RADIO ASTRONOMICAL SPECTRAL ANALYSER : TOWARDS IIIZW35 RECONQUEST (WedAmOR8)

Author(s) : Rodolphe Weber (LESI, france) Lionel Amiaud (LESIA, france) Andrée Coffre (Nançay, france) Laurent Denis (Nançay, france) Alain Lecacheux (LESIA, france) Carlo Rosolen (LESIA, france) Cédric Viou (Nançay, france) Philippe Zarka (LESIA, france)

Abstract : In radio astronomy, the radio spectrum is used to detect weak emission from celestial sources. By spectral averaging, noise estimation is reduced and weak sources can be de-tected. However, more and more observations are polluted by man-made radio frequency interferences (RFI). The im-pact of these RFI on spectral measurement ranges from total saturation to tiny distortions of the data. To some extent, the final spectral estimation can be preserved by blanking in-fected channels in real time. With this aim in view, a com-plete real time processing line has been implemented on a set of FPGA and DSP. The current functionalities of the sys-tem are high dynamic range (at least 70 dB), band selection facilities (from 875 kHz to 14 MHz), high spectral resolu-tion through polyphase filter bank (up to 8192 channels with 49152 coefficients) and real time time-frequency blanking with a robust threshold detector.

Menu