Methods and apparatus for analog to digital conversion
US4683456A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 28, 1983 |
| Grant date | Jul 28, 1987 |
| Priority date | — |
| Expiry date | Dec 28, 2003 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03M1/64
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
Methods and apparatus are described for generating a digital representation of an analog condition. In one method high-frequency digital signals are generated with the frequency of each signal being constant and the frequencies bearing a harmonic relationship one to the other. A representation of the analog condition is applied to cause a shift in phase in at least one of the digital signals. The digital signals are then compared to obtain a measure of the phase shift which is utilized to adjust the phase of the phase shifted signal toward its original phase condition. As a result of the measure of phase shift, there is generated a single weighed digital function which is representative of the amplitude of the adjustment utilized to return the phase shifted signal toward its original phase shifted condition. The single weighed digital function is applied to a low-pass digital filter to produce a multi-bit digital word representative of the instantaneous value of the analog condition. Apparatus of invention comprises a pair of oscillators whose frequencies are constant, harmonically related to one another and whose outputs are time spaced digital pulses. An analog condition responsi…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.