Active feedback system for suppression of alternating magnetic fields
US5465012A · kind A · utility
Inventor
Key dates
| Filing date | Dec 30, 1992 |
| Grant date | Nov 7, 1995 |
| Priority date | — |
| Expiry date | Dec 30, 2012 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B15/00
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
The present invention features a magnetic field compensation system for suppressing alternating or time-varying magnetic fields in a large volume of space. A magnetic sensor detects within a predetermined range of frequencies and generates a signal. A coil or pair of Helmholtz drive coils is positioned into a volume containing the magnetic sensor. A preamplifier is connected to the magnetic sensor for amplifying the signal. A signal processor is connected to the preamplifier for receiving the signal and for providing phase correction and gain. The signal processor has both an averaging and an absolute peak detector for determining magnetic field average and peak excursions. A power amplifier is connected to the coil or pair of Helmholtz drive coils and to the signal processor for receiving and amplifying the processed signal and for applying it to the coil or pair of Helmholtz drive coils.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.