Digital signal processing hardware for a fast fourier transform radio telescope

Abstract

21-cm tomography is a devoloping technique for measuring the Epoch of Reionization in the universe's history. The nature of the signal measured in 21-cm tomography is such that a new kind of radio telescope is needed: one that scales well into very large numbers of antennas. The Omniscope, a Fast Fourier Transform telescope, is exactly such a telescope. I detail the implementation of the digital signal processing backend of a 32-channel interferometer designed to help characterize the non-digital parts of the system, starting at the point analog signal enters the FPGA and ending when it is written to a file on a computer. I also describe the accompanying subsystems, my implementation of a scaled-up, 64 channel design, and lay out a framework for expanding to 256 channels.