HIGH DYNAMIC RANGE DIGITAL FLUXGATE MAGNETOMETER

摘要

An improved digital fluxgate magnetometer (20) that uses digital logic and a high resolution digital to analog converter (40) to digitize a magnetic signal for use by signal processing algorithms. The magnetometer includes an oscillator (11) that outputs an oscillator signal and a magnetic fluxgate sensor (13) having a drive coil (13a) coupled to the oscillator, a feedback coil (13b), and a sense coil (13c). An analog multiplier (14) is coupled to the sense coil and the oscillator and outputs a signal to an analog low pass filter (21). A comparator (22) is coupled to the analog multiplier, and a register (23) is coupled to the comparator and outputs a logical 1 or a logical 0 in accordance with the output of the comparator. A digital filter (27) receives the output of the register and produces a digital output of the digital fluxgate magnetometer. A high resolution digital to analog converter (40) is coupled between the register and the feedback coil of the magnetic fluxgate sensor in a feedback loop of the sensor. The digital to analog converter produces a very high resolution digitized output (typically > 22 bits) that is necessary to adequately represent the dynamic range of the sensor.