Abstract
An optical sub-carrier multiplexed cable TV involves the serious drawback of clipping-induced impulsive distortion by a laser diode. Multi carrier signals have higher probability of being clipped than a single carrier signal, because of their relatively high peak to average power ratio. In order to clarify the characteristics of the clipping-induced distortion for multicarrier signals, here we consider OFDM (Orthogonal Frequency Division Multiplexing) signals. This paper compares three models for clipping : (1) restriction on absolute value of instantaneous amplitude in RF signals as a model for nonlinear amplifier ; (2) restriction on negative instantaneous amplitude in RF signals as a model for laser-diode ; and (3) restriction on root mean square value of base-band in-phase and quadrature-phase signals as a model for pre-restriction of baseband signals. In each case, characteristics of the clipping-induced impulsive distortion for OFDM signals are discussed.
