A Scalable Correlator Architecture Based on Modular FPGA Hardware, Reuseable Gateware, and Data Packetization

摘要

A new generation of radio telescopes is achieving unprecedented levels of sensitivity and resolution, as well as increased agility and field of view, by employing high-performance digital signal-processing hardware to phase and correlate signals from large numbers of antennas. The computational demands of these imaging systems scale in proportion to BMN2, where B is the signal bandwidth, M is the number of independent beams, and N is the number of antennas. The specifications of many new arrays lead to demands in excess of tens of PetaOps per second. To meet this challenge, we have developed a general-purpose correlator architecture using standard 10-Gbit Ethernet switches to pass data between flexible hardware modules containing Field Programmable Gate Array (FPGA) chips. These chips are programmed using open-source signal-processing libraries that we have developed to be flexible, scalable, and chip-independent. This work reduces the time and cost of implementing a wide range of signal-processing systems, with correlators foremost among them, and facilitates upgrading to new generations of processing technology. We present several correlator deployments, including a 16-antenna, 200-MHz bandwidth, 4-bit, full-Stokes parameter application deployed on the Precision Array for Probing the Epoch of Reionization.