In this paper, a fully automatic pitch synchronous method to derive the voice source characteristics starting from the speech signal itself, and fitting them to a parametrized model, is presented. It does not require additional signals for the closed-phase alignment, like the ECG, and uses a fitting procedure that guarantees a good convergence. Further- more the method seems to work reliably even for the closed phase where the analysis interval becomes short. For the automatic finding of the glottal closure instants the method uses a modified version of a previous epoch-detection method. This modification consists of the application of linear detectors to improve performance and reliability mainly in the high-frequency energy speech signals. The method does not require user interaction during the analysis execution. In addition, the required computational load permits its integration in a personal computer environment.