Saturday, August 9, 2008

Modulation Powerline Communication

PLC (Powerline communication) must work with the signal power / low frequency. Because of high frequency radiation can occur from power cable that can disrupt the frequency of others. This is contrary to the provisions of the SNR because of a variety of high interference can occur. The process of achieving a good SNR value of the constraints faced by the emergence of radiation effects power cable. But the problem can be solved with the methods of modulation:

1. Modulation CDM (Code division multiplexing) or spreads spectrum
Signal information can be scattered in a wide frequency range. The level of the signal information is made with very low expectations will not be subject to the noise level is very high in the PLC.

2. Modulation OFDM (Orthogonal Frequency division multiplexing)
Modulation method is quite stable. Modulastion efficiency can reach 5 bits per Hz higher modulation from the other.