Bar code detecting circuitry
US5461223A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 9, 1992 |
| Grant date | Oct 24, 1995 |
| Priority date | — |
| Expiry date | Oct 9, 2012 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S235/901
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A wide bandwidth slope detector has a comparator with first and second time constant circuits coupled to first and second inputs thereof. Where one time constant is on the order of three times the other, the comparator will change state in response to the slopes of an input analog signal coupled to the time constant circuit. Feedback can be provided by a fixed resistor or by a tracking circuit. A smoothing or clipping circuit can be used to pre-process the input analog signals to eliminate noise therefrom. A bar code reading system combines first and second clipping circuits to smooth the highs and lows of the input signal, coupled to a slope detector. The tracking circuit can be used to provide a symmetrical hysteresis characteristic.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.