Patent ID: 6204661
Filing Date: 2001-03-20
Classification: G01R

Abstract:
A detector for a magnetic field having a low frequency compared to background EMF and having a magnitude approximately 1,000 times less than said EMF, said detector comprising:a pickup coil for capturing said magnetic field and said background EMF;an integrator coupled for receiving a signal having respective components representative of said magnetic field and said background EMF, said integrator having a time constant such that successive positive and negative polarity portions of said component representative of said background EMF cancel out one another in said integrator, but said component representative of said magnetic field results in a net output signal from said integrator, said net output signal being indicative of said magnitude of said magnetic field;a magnetic field strength output indicator responsive to said net output signal from said integrator; anda threshold circuit for equalizing amplitudes of detected magnetic waves to provide uniform operation of said output indicator irrespective of distance of a source of said detected magnetic waves from said detector,whereby said magnetic field can be detected with great sensitivity notwithstanding said background EMF.