Frequency selective detecting system for detecting alternating magnetic fields
US3983475A · kind A · utility
8Cited by
2References
2Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Dec 30, 1974 |
| Grant date | Sep 28, 1976 |
| Priority date | — |
| Expiry date | Dec 30, 1994 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R33/04
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A system for detecting an AC magnetic field of a desired frequency using a magnetic sensing element of the parametrically excited second harmonic oscillator, in which a reference signal having a repetition period substantially equal to the repetition period of the AC magnetic field is adopted for synchronous detection of the detected output of the magnetic sensing element, and in which a current proportional to the intensity of a noise magnetic field is applied to the oscillation winding of the magnetic sensing element to lessen the influence of the noise magnetic field to greatly improve the SN ratio of the detected signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.