The method uses a physical phenomenon of dispersion of the optical rotation for identification of the spectral characteristics of light Polychromatic linearly polarized radiation passes through the environment that rotates a polarization plane of its spectral components, depending on their wavelength. The module comprises a latch mechanism for latching the plug-in module in the end mounting position in the reception member. , a cable system, a broadcast program stream is transmitted to broadcast programming content, and the broadcast program stream is recorded in a headend of the system to enable a user to perform network private video recorder functions on the programming content in the recorded program stream. The curve fitting of the phase is performed using linear techniques in one embodiment; an average phase and appropriate sloperamp are calculated to match the phase as accurately as possible.