Delta-sigma modulator for an analog-to-digital converter with low thermal noise performance
US5274375A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 17, 1992 |
| Grant date | Dec 28, 1993 |
| Priority date | — |
| Expiry date | Apr 17, 2012 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03M3/452
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
An analog-to-digital converter includes a two-bit delta-sigma modulator. The delta-sigma modulator is comprised of a first stage integrator (10) that feeds a noise shaping circuit (18). The output of the noise shaping circuit (18) is input to a two-threshold imbedded ADC (20) to provide the two-bit output. This output of the imbedded ADC (20) is input to a digital filter (22) to provide the filtered digital output, this filtering high-frequency noise. The output of the imbedded ADC (20) is also fed back through a three-level DAC (24) to a summing junction on the input of the integrator (10). The three-level DAC 24 has three states that are output with one state being a "do nothing" state. The thermal noise performance of the delta-sigma modulator as a function of the quantizer threshold voltages is first simulated and then the value of the quantizer thresholds selected to provide optimum signal-to-thermal noise performance.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.