Patent ID: 9025700
Filing Date: 2015-05-05
Classification: H03F,H03M,H04L

Abstract:
1. A digital polar modulator (DPM) for transforming a baseband signal into a modulated digital modulator output signal, the digital polar modulator comprising an input unit, which has a first input part that is configured to receive an amplitude modulating baseband signal component, and which has a second input part that is configured to receive a phase modulating baseband signal component; two low-pass delta-sigma modulators, a first one being connected downstream from the first input part and configured to provide at its output a first pulse train in dependence on the amplitude-modulating baseband signal component, and a second one being connected downstream from the second input part and configured to provide at its output a multilevel quantized signal in dependence on the phase modulating baseband signal component; a multiphase generator, which is configured to provide at its output a set of square-wave carrier signals having a common carrier frequency and exhibiting discrete phase shifts with respect to each other; a multiplexer, which is connected on its input side with the multiphase generator to receive in parallel the set of carrier signals, and which has a select input connected to the second delta-sigma modulator, and which is configured to provide a multiplexer output signal that is formed by switching, in dependence on the signal received at the select input as a function of time, between selected ones of the carrier signals; and a combiner unit that is configured to provide at its output the digital modulator output signal as a combination of the multiplexer output signal and an output signal of the first delta-sigma modulator.