A calibration of a loop gain in a digital servo system is presented. The loop
gain
can be calibrated measuring the response in a control signal generated by the digital
servo system when the control signal is replaced by a sum of the control signal
and a sinusoidal disturbance. The loop gain can be set to provide a desired gain,
for example unity, between the control signal and the sinusoidal disturbance at
a cross-over frequency.
