The δ-function of current which represents an electron traveling in a straight line is Fourier analyzed into a spectrum of infinite linear harmonic currents, having spectral distributions both in frequency and phase velocity. The radiation (and induction) fields associated with these currents are associated either with Cherenkov radiation or with acceleration or deceleration radiation (“bremsstrahlung” in the literal sense) according to whether the velocity of the electron exceeds or is less than that of light in the medium. The analysis of the two situations is identical; indeed, the two types of radiation cannot, in general, be sharply distinguished.