Flexible Filter Bank Based on an Improved Weighted Overlap-Add Algorithm for Processing Wide Bandwidth Radio Astronomy Signals

Abstract

Wideband signals from a radio telescope have to be channelized for spectral observations or for dedispersion for pulsar observations. A polyphase filter bank is designed based on the improved weighted overlap-add (IWOLA) algorithm to achieve channelization. The IWOLA algorithm involves applying an equivalent Hilbert transform to the normal WOLA filter bank by shifting the center frequency of every sub-band by a half of the frequency bin, so that the IWOLA filter bank provides K independently output complex subbands instead of the usual K + 1 sub-bands, reducing the subsequent processing units by one set. Performance of the proposed IWOLA filter bank is analyzed by means of MATLAB simulations. We show how the IWOLA filter bank can be used for a two-stage, high-resolution spectrometer, with a much reduced consumption of FPGA on-chip block RAM.