By Shlomo Ovadia, Chinlon Lin, and William T. Anderson
The performance characteristics of the 16- VSB cable modem was measured in a hybrid AM/16-VSB lightwave video transmission system using three different laser transmitters with the 16-VSB signal 6 dB below the AM carriers. The hybrid video lightwave system based externally-modulated laser transmitters had s 1.5 dB reflection-independent penalty due to impulse noise with a operating margin :2:9.1 dB for the 16-VSB signal even at high reflection levels (:2: -30 dB). In contrast, the hybrid video lightwave system-based directly-modulated DFB laser transmitter showed a 2.4 dB penalty due to impulse noise with a 9.6 dB operating margin at low reflections with no operating margin if the reflections are above -35 dB. However, for good performance of the AM channels, reflections less than -50 dB are needed.