shows the operating principle of the extremum-
seeking algorithm. The frequency setpoint is modulated with
a frequency modulation (FM) dithering signal with the FM
rate ν, the FM amplitude fA , and a variable center frequency
fc . The modulated frequency setpoint f (t) of the frontend
results in a modulated output voltage Vout (t) that contains
different harmonics of ν due to the nonlinear mapping from f to
Vout . Near f0 , the output voltage Vout (f ) can be approximated
parabolically