US 9,810,756 B2
Zero- and low-field transport detection system
Corey Cochrane, Burbank, CA (US); and Patrick M. Lenahan, Boalsburg, PA (US)
Assigned to The Penn State Research Foundation, University Park, PA (US)
Filed by Corey Cochrane, Burbank, CA (US); and Patrick M. Lenahan, Boalsburg, PA (US)
Filed on Oct. 10, 2013, as Appl. No. 14/50,615.
Claims priority of provisional application 61/712,323, filed on Oct. 11, 2012.
Prior Publication US 2014/0247048 A1, Sep. 4, 2014
Int. Cl. G01V 3/00 (2006.01); G01R 33/385 (2006.01); G01N 24/10 (2006.01); G01R 33/24 (2006.01); G01R 33/32 (2006.01)
CPC G01R 33/385 (2013.01) [G01N 24/10 (2013.01); G01R 33/24 (2013.01); G01R 33/323 (2013.01)] 18 Claims
OG exemplary drawing
 
1. A sensing apparatus for detecting and determining the magnitude of a static magnetic field, the apparatus comprising;
a first set of coils capable of producing a sweeping, quasi static, magnetic field when driven by a direct current;
a second set of coils, for magnetic field modulation, positioned between the first set of coils capable of producing an oscillating magnetic field when driven by an oscillating current;
a precision, bipolar current controller which drives current through the first set of coils to create a linearly sweeping magnetic field;
a signal generator which drives an oscillating current through the second set of coils to create an oscillating magnetic field to modulate the field produced by the first set of coils;
a voltage biased, semiconducting device with a known, low magnetic field magnetoresistance properties positioned in between both sets of coils and having a semiconducting device current;
an analog front end which conditions the semiconducting device current before being sampled;
an analog-to-digital converter which samples the conditioned semiconducting device current; and
a signal processing unit capable of demodulating the conditioned sampled semiconducting device current and recording changes in this signal as a function of sweeping, quasi static magnetic field.