The authors have developed a computing system to deal with the Doppler signals. They show how the programmes work, which make it possible both to print the classic curve by calculating the indices, and also to carry out a spectrum analysis. This technique makes it possible to evaluate the extent of stenoses and turbulence, particularly in the area of the carotid bifurcations. Computing improves the quality of vascular evaluations by non-invasive methods, it enables town-laboratories to follow in the best possible way the progress achieved by the new parometers and the complementary investigations of the classic Doppler.