| Due to consumer demand for wireless devices that support multimedia services ranging from voice and data transfer to video on demand, there is a need for flexible and adaptable base stations. These systems are typically implemented using a wide-band receiver that captures and digitizes the entire cellular band which contains multiple wireless standards. In order to digitize the entire cellular band, there is a requirement for wide bandwidth, high-resolution analog-to-digital converters (ADCs). In general, these ADCs are hard to realize and require some form of calibration to meet the requirements. In this thesis, two novel digital background calibration techniques targeted for pipeline and piΛSigma architecture ADCs are reported. The two calibration schemes are realized by introducing a redundancy in the system. For the pipeline architecture converters, two extra stages located at the end of the pipeline are implemented and are active only during calibration process. This calibration is suitable for implementation in a fully monolithic pipeline ADCs. For the piΛSigma architecture converters, an extra channel that is linearly dependent on the piΛSigma channels is implemented to correct for channel gain mismatches. All channels are calibrated simultaneously, and calibration of the overall system depends on the convergence rate of a recursive-least-squares algorithm. |
