Power quality measurement is a key issue with the technology advance in power systems. One fo these issues is harmonics estimation of power systems signals. This work shows an algorithm to obtain, simultaneously, the real values of frequency, amplitude and phase of each signal component, based in distorted values originated by the use of FFT. In contrast to other methods, the algorithm requires a small number of data, allowing its implementation in real time. To extended this method to a high harmonic order signal, filter banks are used to decompose it in sub bands and eventually reconstruct it, in a real time operation structure. This work shows results testing the correct operation and robustness of the process. Th eAlgorithm is optimized to its imlementation with a reduced number of float point operations.