I will using the ADA2200 as the basis for reverse engineering an old spinner magnetometer (formerly electron tube technology) that analyzes archaeological samples by spinning them between two coils and comparing the phase and amplitude of the residual magnetism in the three axes of the cubic sample to the encoder signals from the motor to determine the orientation relative to magnetic north. The samples are cast and marked with the current magnetic north orientation in the field. This is compared with a map of the magnetic north as it moves in time to determine another data point for the age of the samples. The motor, powered by a variable frequency drive is equipped with a quadrature encoder (US Digital E5) providing an index pulse plus 2048 pulses/revolution. Motor speed is from about 1000 to 6000 rpm, resulting in a 10 Hz to 100 Hz roughly sinusoidal signal out.