Optimizing the Performance of Very Wideband Direct Conversion Receivers

03/12/1027 Introduction Zero-IF receivers are not new; they have been around for some time and are prominently used in cell phone handsets. However their use in high performance wireless base stations has had limited success. This is due primarily to their limited dynamic range and that they are less well understood. A new wide bandwidth zero-IF IQ demodulator helps relieve the dynamic range and bandwidth shortcomings for main as well as DPD (digital predistortion) receivers, and enables 4G base stations to cost effectively address the ever-increasing bandwidth needs of mobile access. This article discusses how to optimize performance by minimizing IM2 nonlinearity and DC offset that reduce the dynamic range of zeroIF receivers, thus offering a viable alternative to an otherwise challenging design.