Communication unit, digital band-pass sigma-delta modulator and method therefor
US9166617B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 18, 2014 |
| Grant date | Oct 20, 2015 |
| Priority date | — |
| Expiry date | Dec 18, 2034 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L27/368
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A communication unit comprises a power DAC. The DAC comprises: a switched mode power amplifier (SMPA); and a digital band-pass sigma-delta modulator operably coupled to the SMPA. The sigma-delta modulator comprises an input to receive an input baseband signal; a delay; an adder module arranged to add a feedback signal with an output from the delay; and at least two feedback branches. The sigma-delta modulator is arranged to digitally oversample the input baseband signal such that a ratio of a sampling frequency employed by the sigma-delta modulator to a radio frequency (RF) output from the DAC is fixed and the sampling frequency tuned or wherein the sampling frequency is fixed and the ratio is adjusted, such that a first feedback branch in the sigma-delta modulator is formed using at least one from a group of: a zero gain, an additive inverse of a second feedback branch.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.