Second order demodulator for sigma-delta digital to analog converter
US5821891A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 26, 1996 |
| Grant date | Oct 13, 1998 |
| Priority date | — |
| Expiry date | Dec 26, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03M3/502
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A demodulator subsystem incorporates second-order filtering for use within a sigma-delta DAC. A conventional demodulator is modified to include circuitry which manifests a second-order filtering response to the output of the demodulator. The added circuitry includes an additional pair of phased switched capacitor legs and a fixed capacitor. The combination of the additional circuitry with the existing phase switched and fixed capacitors of the conventional demodulator creates an additional pole which provides second order filtering to the demodulator output, effectively eliminating the high-order post filtering and minimizing both the circuit area required for implementation of the demodulator and its power consumption.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.