Digital-to-digital conversion using nonuniform sample rates
US5892468A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 16, 1997 |
| Grant date | Apr 6, 1999 |
| Priority date | — |
| Expiry date | Jan 16, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03L2207/50
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A method and apparatus for digital-to-digital conversion using sigma-delta modulation of the temporal spacing between digital samples. The method and apparatus of the present invention provides for sigma-delta modulation of the time base such that noise produced by NONUNIFORM sampling are frequency-shaped to a region (i.e., shifted to higher frequencies where it can be removed by conventional filtering techniques. In one embodiment, the digital data is interpolated (16) by fixed ratio and then decimated (21) under control of a first sigma-delta modulated frequency selection signal (26) that represents, on average, the data rate of the incoming digital data stream. Thereafter, the digital data is interpolated (30) under control of a second sigma-delta modulated frequency selection signal (46) that represents, on average, the data rate of the digital data to be output by the converter and then decimated (40) by a fixed ratio. In another embodiment, the digital data is interpolated under control of a first sigma-delta modulated frequency selection signal that represents, on average, the data rate of the incoming digital data stream and then decimated by a fixed ratio. Thereafter, the …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.