Digital/analog converter
US5323159A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 22, 1991 |
| Grant date | Jun 21, 1994 |
| Priority date | — |
| Expiry date | Apr 22, 2011 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03M1/68
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A D/A converter divides an input digital data into at least two overlapping digital ranges. The data in the two ranges are converted separately from digital to analog by a low-range and a high-range DAC. The resulting analog signals are then added with a weighting that maintains the proper loudness relationships in the final combined analog output. In a low range of amplitudes, only the low-range DAC performs D/A conversion. Above a predetermined amplitude threshold, some of the high significant bits to the low-range DAC are frozen, while a remaining low significant bits of the low-range DAC are permitted to vary with the input digital data. Above the predetermined amplitude threshold, a digital value is subtracted from the data fed to the high-range DAC. The subtracted value is equal to the frozen value in the low-range DAC. In some embodiments, one or more supplementary bits are developed to smooth the transition between ranges. In other embodiments, more than two DACs receive overlapping ranges of the input digital data. In some of the embodiments, positive and corresponding negative analog representations of the ranges are connected in push-pull.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.