Analog-to-digital converter using dither and method for converting analog signals to digital signals
US5889482A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 6, 1997 |
| Grant date | Mar 30, 1999 |
| Priority date | — |
| Expiry date | Oct 6, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03M3/458
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
An analog-to-digital converter (100) has a first path (110) with a first sigma-delta modulator (114) which transforms an analog input signal X.sub.0 (111') from an input terminal (101) to a digital output signal Y.sub.0 at an output terminal (102). In a second path (120), a digital dither signal D (121') is combined with a digital intermediate signal Z.sub.0 (115') from the first modulator (114) and digitally processed by a second sigma-delta modulator (124) to an intermediate signal Y.sub.1 (125') Y.sub.1 is fed to the first modulator (114) and to the output terminal (102) with opposite sign ("+" and "-", respectively). Thereby, multipliers (133 and 127) attenuate Y.sub.1. The dither signal D (121') is used substantially only within the converter (100), and is substantially canceled before the output terminal (102). This features preserve a high SNR of the converter (100) and low spectral tones in output signal Y.sub.0.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.