Fluxgate: tuned vs. untuned output

Fluxgate voltage output contains information about the measured DC magnetic field in amplitude of even harmonic components. Tuning the sensor output causes the concentration of output energy to specific harmonics (usually 2f) and parametric amplification. A short-circuited output current fluxgate cannot be tuned, but it in principle requires less turns of the pick-up coil. The noise measurements performed on amorphous ring-core sensors show no significant difference between current-output and tuned voltage-output, and higher noise level for untuned voltage-output