Development of multi-stage filter banks for ASKAP

Radio astronomy instrumentation is continually seeking greater processing bandwidths whilst maintaining output frequency resolutions of order one kHz per channel. With the recent commercial availability of multi Giga sample per second analog to digital converters, instantaneous processing bandwidths of the order of hundreds of MHz to many GHz are now viable for radio astronomy applications. This is driving the design of more efficient filter-bank architectures to manage the significant frequency channelisation task. In this paper we present a new multi-stage filter-bank for the ASKAP instrument. We cover the filter-bank architecture, some of the design constraints governing its implementation, and considerations relating to the filter-bank outputs.