Device and method for direct mixing of pulse density modulation (PDM) signals
US8937515B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Oct 23, 2013 |
| Grant date | Jan 20, 2015 |
| Priority date | — |
| Expiry date | Oct 23, 2033 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04R3/005
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A device for mixing multiple (N) pulse density modulated (PDM) bit streams of a bit rate, the device comprises an input logic, an error accumulation circuit, an error correction circuit and an adder of more than N bits; wherein the device is arranged to output an output PDM bit stream that represents a mixture of the multiple input PDM bit streams; wherein the output PDM bit stream comprises a plurality of output PDM bits, wherein a certain output PDM bit of a plurality of output PDM bits that form the output PDM bit stream is generated during a certain clock cycle; wherein the input logic is arranged to select, during each fraction of the certain clock cycle, a current bit of a selected PDM bit stream, wherein different PDM bit streams are selected during different fragments of the certain clock cycle; wherein the error accumulation circuit is arranged to store intermediate values during a first fraction till a penultimate fraction of the certain clock signal and to store a last value during a last fraction of the certain clock signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.