The ISL5216 Quad Programmable Digital Downconverter (QPDC) is designed for high dynamic range applications such as cellular basestations where multiple channel processing is required in a small physical space. The QPDC combines into a single package a set of four channels which include: digital mixers, a quadrature carrier NCO, digital filters, a resampling filter, a Cartesian-to-polar coordinate converter and an AGC loop.