python 4 ltspice 3 ultrasonic-transducer 2 rms-amplitude 2 resistance 2 pycharm-ide 2 phase 2 non-linear-distortions 2 linear-network 2 inductance 2 frequency 2 fourier-series 2 complex-signals 2 analog-discovery-2 2 ac-bridge 2 current 2 kirchhoff-voltage-law 2 least-sqaure-method 2 least-square-fit 2 least-square-regression 2 matrix-equations 2 ohms-law 2 overdetermined 2 scipy-library 2 voltage 2 transfer-function 1 circuit 1 kirchoff-current-law 1 linear-equations 1 ltspice-simulation-files 1 harmonics 1 average-amplitude 1 angular-frequency 1 waveform 1 transfer-functions 1 spectrum 1 harmonic 1 linear-systems 1 kirchhoff-current-law 1 electrical-circuits 1