Digital flux gate magnetometer

Abstract

Digital logic and a high resolution digital to analog converter are used to adequately digitize a magnetic signal that is subsequently processed by magnetic data processing algorithms. The high resolution digital to analog converter is directly incorporated in a feedback loop of a magnetometer sensor, an expensive precision analog to digital converter is replaced by a less expensive, lower power digital to analog converter. The circuit improvement provided by the present invention includes an analog low pass filter coupled to the sensor, a digital logic circuit coupled to the analog low pass filter for providing an output signal from the magnetometer and a feedback output signal, and the digital to analog converter coupled between the digital logic circuit and a feedback coil of the sensor for coupling the feedback output signal thereto. The digital logic circuit includes an analog to digital converter, an adder having a first input coupled to the analog to digital converter, and an accumulator coupled between an output of the adder and a second input of the adder. The digital logic circuitry processes the error signal from the analog multiplier, eliminates high frequency components, and digitizes the result. Thus, a low resolution analog to digital converter, having a resolution of only a few bits, may be used.