Inductive loop detector
US4639689A · kind A · utility
4Cited by
2References
16Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Aug 27, 1985 |
| Grant date | Jan 27, 1987 |
| Priority date | — |
| Expiry date | Aug 27, 2005 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03L7/085
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
An inductive loop has its frequency of oscillation controlled by means of a counter, a reference frequency source, a comparator, and an attenuator. The frequency of the loop is compared by the comparator to the frequency of the reference source to produce an error signal which controls the attenuator. The amplitude of the output signal of the attenuator is used to adjust the loop frequency to a desired value.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.