Abstract
The invention relates to a measurement device for measuring weak magnetic fields, such as fields in the sub-picotesla range (e.g. lower than a few nanotesla). The measurement device comprises ultrasensitive magnetic sensors (or arrays of ultrasensitive magnetic sensors) coupled to low-noise processing circuitry. The processing circuitry comprises a two-stage design including low-noise amplifiers and analog filters. The invention is suitable for magnetocardiovascular (MCV) applications thanks to its ability to measure very small magnetic fields with good accuracy and very little noise.