Optical digitizer for measuring spirometer output
US4307729A · kind A · utility
7Cited by
4References
6Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Jan 3, 1980 |
| Grant date | Dec 29, 1981 |
| Priority date | — |
| Expiry date | Jan 3, 2000 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01F17/00
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A spirometer includes an expansible chamber of the piston type fitted with an indicia strip. The indicia comprise two columns of alternating light and dark bars. The columns are offset from one another by one-half the thickness of a bar and are respectively viewed by two photodetectors which generate signals which are shifted 90.degree. from one another as the columns pass through their respective fields of view. The signals are continuously sampled as digital words and consecutive words are compared to determine whether a counter should be incremented or decremented by one or two counts.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.