Uniform signal contribution of the step function modulated sine wave

A canonical problem in the theory of ultrawideband pulse propagation through temporally dispersive, absorptive materials is the propagation of a step function signal through a dielectric material that exhibits anomalous dispersion. Sommerfeld and Brillouin provided the first closed-form approximation of the dynamic evolution of this waveform through a single-resonance Lorentz model dielectric. An improved approximation was then provided by Oughstun and Sherman with use of modern, uniform asymptotic methods. Here, corrections to this expansion are presented which results in a complete uniform asymptotic description