Electro-optical speed transducer
US4037157A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 5, 1976 |
| Grant date | Jul 19, 1977 |
| Priority date | — |
| Expiry date | Apr 5, 1996 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01P3/486
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A speed transducer for measuring the speed of a moving surface comprises a light chopper for alternately completing and breaking the respective light paths between a light source and first and second photodetectors such that the second light path is completed before the first light path is broken. A pulse generator produces a pulse having a duration which is determined by the time interval between completion of the first and second light paths. A converter converts the pulse to a direct current signal proportional to the speed of the moving surface by generating a comparison pulse, the width of which is controllable by a direct current control signal, and comparing the widths of the generator and comparison pulses to produce an error signal which is indicative of the difference in widths. A control signal is generated in response to the error signal which constitutes the desired output when the compared pulse widths are equal. In a second embodiment, the sum of two pulses representing the speed of a rotating surface at two opposed locations is integrated to produce a direct current signal proportional to the concentric rotational speed only.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.