Digital-to-analog converter with delta-sigma modulation
US5245345A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 11, 1991 |
| Grant date | Sep 14, 1993 |
| Priority date | — |
| Expiry date | Oct 11, 2011 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03M3/50
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
The digital-to-analog conversion apparatus operates in synchronization with a system clock signal having a short period to oversample and delta-sigma-modulate a digital input to produce a requantized digital signal. The system clock signal is mixed with noise leaked back due to the oversampling and delta-sigma modulating operation. The system clock signal is frequency-divided by the rate of one-fourth or less to produce a divided clock signal having a long period and being free of the noise. The requantized digital signal is detected each long period, and is pulse-modulated according to the detected results to generate a pulse signal having the long period. This pulse signal is low-pass-filtered to produce an analog output having improved S/N ratio.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.