Additive & Spectral: Partial Tracking
Partial tracking is the process of detecting single sinusoidal components in a signal and obtaining their individual amplitude, freuquency and phase trajectories.
Monophonic

STFT
A short term fourier transform segments a signal into frames of equal length.
Fundamental Frequency Estimation  YIN (de Cheveigné et al, 2002)  Swipe (Camacho, 2007)

Peak Detection
For every STFT frame, local maxima are calculated in the range of integer multiples of the fundamental frequency.
Trajectories of partial amplitudes for a violin sound.
Trajectories of partial frequencies for a violin sound.
Trajectories of unwrapped partial phases for a violin sound.