Building Billion-Tap Filters: Prism Signal Processing

Signal processing engineers recognize two main classes of filter: finite impulse response (FIR) and infinite impulse response (IIR), each with distinct properties. The Prism is a new filter type that combines the best of both: the numerical stability and linear phase of FIR together with the low-cost calculation of IIR. Here, we show how to build ultranarrowband FIR filters containing over one billion samples (taps) using a sequence of Prisms. While designing and operating equivalent conventional FIR filters would require supercomputer resources, these Prism filters are designed instantly and implemented on a single field-programmable gate array (FPGA).