Bipolar magnetometer sensor similar to fluxgate device but having equal input and output sinusoidal frequencies and zero Barkhausen noise

A new bipolar magnetometer, having a sensitivity of 80 mu V/nT for 46 turns in each sensor differential output coil, is presented. Merits of the sensor include equal input and output sinusoidal frequencies, zero Barkhausen noise, high sensitivity, ruggedness, and simplicity. The basic magnetic theory involved, the phase-sensitive detector system, and the input-output characteristic of the sensor are also described.