The present codes are Matlab functions for spectral processing of a signal via Fourier analysis and synthesis. One may obtain the amplitude and phase spectrum of the signal by transforming into the frequency domain, adjust some (or all) spectral components appropriately and then transforming back into the time domain.
The “sgn_analysis.m” function provides a computation of the:
1) one-sided amplitude spectrum;
2) one-sided phase spectrum;
3) frequency vector.
The “sgn_sinthesis.m” function provides a computation of the:
1) signal in the time domain;
2) time vector.
An example is given in order to clarify the usage of the functions. For convenience, the input and output arguments are given in the beginning of the functions.
The codes are based on the theory described in:
 N. Majumdar, S. Banerjee. MATLAB Graphics and Data Visualization. Birmingham, Packt Publishing, 2012.
 D. Manolakis, V. Ingle. Applied Digital Signal Processing. Cambridge, Cambridge University Press, 2011.
 U. Zölzer. DAFX: Digital Audio Effects. Chichester, John Wiley & Sons, 2011.