Here is an example of why multiple carriers make sense in power-line communications, as explained by Atheros Communications. A review of the transmission qualities of the typical home power-line system shows a series of peaks and notches at specific frequencies. This is called multipath distortion and arises because transmitted signals typically reach a receiver via different paths, some longer and more lossy than others. If a carrier frequency happens to sit at a spectral notch, it can be too weak for the receiver to demodulate. OFDM techniques use numerous carriers to ensure at least some of them will be strong enough when they arrive at a receiver.