APPARATUS AND METHOD FOR REDUCING THE EFFECTS OF NOISE ON A LIGHT TRANSMITTER

摘要

According to the present invention, an apparatus and a method that reduce the effects of noise on a light transmitter (140) are disclosed. The current invention is particularly suited to Hybrid Fiber Coax networks. Embodiments of the current invention shape one or more pre-selected, noisy spectra of an electrical signal to be transmitted. The shaping primarily reduces errors due to random noise. The shaped electrical signal is then combined with one or more non-shaped signals and the composite signal is converted to light and transmitted. In addition, the non-shaped signals may be notch filtered around frequencies that have a lot of frequency-specific noise. The embodiments of the current invention essentially limit or reduce power in noisy spectra (which could be noisy because of random or frequency-specific noise), which reduces the chances of the light transmitter (140) being overwhelmed in power. This limits the effects of electrical noise on the light transmitter (140). The signal shaping may be performed in the analog or digital domain. By determining the frequency bands that are more likely to be noisy, the current invention reduces complexity, as only those frequency bands that have the most noise are power limited.