n TV channels is measured by the amount of frequency. The amount of frequency is www.TechnicalPDF.com determined by the difference between the highest and lowest frequencies on the coaxial cabling. For example, a 6MHz channel might be within the 60MHz and 54MHz range ( (60 - 54 = 6). Upgrading to gigahertz from megahertz networks adds capacity for additional video channels and higher-speed Internet access for subscribers. See Chapter 7, "Mobile and Wi-Fi Networks," for information on frequencies. Carrying More Data-Quadrature Amplitude Modulation (QAM) QAM is a modulation technology specified in DOCSIS standards that increase broadband capacity on hybrid fiber cable (HFC) networks. Modulation standards define how signals are placed on networks and how they are transmitted. Full Duplex 4096 QAM enables cable TV networks to carry two to three times as many high definition (HD) movies as the earlier 256 QAM. However, movies must be transmitted using the IP (Internet Protocol). DOCSIS 3.1 specifies 4096 QAM to deliver 10 Gigabits of symmetric capacity shared by nodes within neighborhoods. Currently most cable operators don't transmit movies using the IP (Internet Protocol). QAM 4096 is more sensitive to noise and impairments that occur over long distances on coaxial cabling. This is one reason cable TV providers are expanding their fiber footprint closer into neighborhoods. Fiber closer to homes results in shortened coaxial cable lengths. Shorter coaxial cabling runs have less impairment from electrical noise than longer coaxial cable runs. There is also a DOCSIS 3.1 specification for half duplex, asymmetric service. Asymmetric DOCSIS 3.1 specifies 10 Gigabits downstream and 1 Gigabit upstream www.TechnicalPDF.com from customers to the provider's headend. In these instances, DOCSIS 3.0 spectrum is used for the upstream bits toward the cable TV network and DOCSIS 3.1 spectrum for downstream spectrum to subscribers. Upgrading to 10GHz adds capacity for Internet browsing as well as movies sent using IP. Unlike bonding, 