Bandpass sigma-delta analog-to-digital converter (ADC), method therefor, and receiver using same
US5442353A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 25, 1993 |
| Grant date | Aug 15, 1995 |
| Priority date | — |
| Expiry date | Oct 25, 2013 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03M3/414
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A bandpass sigma-delta analog-to-digital converter (ADC) (10) includes first (11) and second (12) bandpass sigma-delta modulators, and a digital filter (13) connected to digital outputs thereof. In the illustrated embodiment, the first bandpass sigma-delta modulator (11) is a second-order, single bit bandpass modulator, and the second bandpass sigma-delta modulator (12) is a first-order, multiple-bit modulator. Coefficients in feedback paths of the first (11) and second (12) modulators are derived from a transfer function of the digital filter. In one embodiment, a receiver (50) for a system such as frequency modulation (FM) radio converts an intermediate frequency (IF) analog signal to digital in-phase (I) and quaternary (Q) signals using the bandpass sigma-delta ADC (10).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.