Analog to digital conversion using non-uniform sample rates
US5485152A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 25, 1994 |
| Grant date | Jan 16, 1996 |
| Priority date | — |
| Expiry date | Oct 25, 2014 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03L2207/50
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A method and apparatus for analog 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 errors produced by non-uniform sampling are frequency-shaped to a region (i.e., shifted to higher frequencies) where they can be removed by conventional filtering techniques. In one embodiment, digital data is interpolated under control of a sigma-delta modulated frequency selection signal that represents, on average, the data rate of the digital data to be output by the converter and then decimated by a fixed ratio. The frequency selection signal is modulated using an n-th order m-bit sigma-delta modulator. Data thus emerges from the interpolation/decimation process at the sample rate selected by the n-th order m-bit sigma-delta modulator. The method and apparatus converts the data rate of an incoming digital data stream from an ADC to the data rate determined by the n-th order m-bit sigma-delta modulator.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.