Coarse/fine A-D converter using ramp waveform to generate fine digital signal
US4804939A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 25, 1987 |
| Grant date | Feb 14, 1989 |
| Priority date | — |
| Expiry date | Aug 25, 2007 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03M1/361
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
Analog-to-digital conversion in which a coarse digital representation of an input analog signal is converted to a coarse analog representation, and the difference between the original analog signal and the coarse analog representation is determined. A ramp waveform signal is generated, and a change in that waveform by an amount substantially equal to the difference between the original analog signal and the coarse analog representation is sensed. A plural bit fine digital signal corresponding to the sensed change of the ramp waveform is produced. The combination of the coarse and fine digital signals constitute the digital representation of the input analog signal. In one embodiment, the ramp waveform is increased until it is equal to the difference between the analog signal and the coarse analog representation, whereupon the ramp waveform is digitized. In another embodiment, the ramp waveform is used to reduce the level of a sample of the analog signal until that sample becomes equal to the coarse analog representation, at which time a counter that had been initiated at the commencement of sample reduction is stopped, the count being equal to the fine digital signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.