We introduce two models for the relaxation modulus: The first is an Analytical Model grounded in the impulse function and Control Theory, well-established in mathematics, nuclear physics, and signal control systems. It utilizes only two constants dependent on the polymer's chemical structure, eliminating the need for ad hoc adjustments. The second, the Unified (Characteristic) Model, builds on the first model's findings, offering a more practical approach by using the measured time-dependent relaxation modulus related to the MWD, w(M). The computational strategy begins with identifying a form of the MWD and its relations using the rapidly analysed Unified Model, then, if necessary, validating these results with the Analytical Model. This section outlines the new method's main principles, utilizing the familiar relaxation modulus, G(t), and describes the process for simultaneously computing the MWD and the broad-range curve of the linear viscoelastic relaxation modulus from simulated measurements of the relaxation modulus.