Patent ID: 9166617
Filing Date: 2015-10-20
Classification: H03G,H03K,H03M,H04L

Abstract:
1. A communication unit comprising a power digital to analog converter comprising: a switched mode power amplifier; a digital band-pass sigma-delta modulator operably coupled to the switched mode power amplifier and comprising: wherein the digital band-pass sigma-delta modulator is arranged to digitally oversample the input baseband signal such that a ratio of a sampling frequency employed by the digital band-pass sigma-delta modulator to a radio frequency (RF) output from the power digital to analog converter is fixed and the sampling frequency is tuned or wherein the sampling frequency is fixed and the ratio is adjusted, such that at least one first feedback branch in the digital band-pass sigma-delta modulator is formed using at least one from a group of: a zero gain, an additive inverse of a second feedback branch.