Advanced digital flux gate magnetometer

Abstract

Digital logic comprising a high speed analog to digital converter, a high speed analog to digital converter, a digital multiplier, and an infinite impulse response filter and decimation circuit are used to 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, and an expensive precision analog to digital converter is replaced by a less expensive, lower power digital to analog converter. The improvement provided by the present invention includes a high speed analog to digital converter coupled between the oscillator and a first input of a multiplier, and a second analog to digital converter that is coupled between the sense coil of the sensor and a second input of the multiplier. The output of the multiplier is coupled to an infinite impulse response filter and decimation circuit that produces the digital output signal from the magnetometer. The output of the infinite impulse response filter and decimation circuit is coupled by way of a digital to analog converter to the feedback coil of the sensor. Depending on the system requirements, the two analog to digital converters, the digital multiplier, and the infinite impulse response filter and decimation circuit may be implemented in one readily available microcontroller at low cost. This serves to reduce the number of components, complexity, and expense of the magnetometer.