Signal processor method and apparatus
US4000397A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 21, 1975 |
| Grant date | Dec 28, 1976 |
| Priority date | — |
| Expiry date | Mar 21, 1995 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03K5/082
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
Method and apparatus for processing input binary encoded analog signals to precisely determine the time occurrence of positive-going and negative-going transitions. Such digital signals result, for example, when bar codes (e.g. Universal Product Codes) are optically scanned. Transitions are determined by detecting the zero crossings, at selected gating times, of the second derivative of the input signals. The selected gating times occur whenever the first derivatives of the input signals exceed a threshold level. The threshold level is determined in one embodiment by peak-to-peak detecting the input signals and adding this value to a rectified noise measurement signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.