Here we go..... A cable system in North America, USA, Canada, Mexico and South America are a broadband system carrying a spectrum of 50 to 750 or 870 MHz from a center point to all the customer where the cable system is distributed. CBS, NBC, ABC are a 6 MHz channel in thes broadband system. The format in North America is called NTSC (6 MHZ wide) In Europe the same TV channel can be PAL-* ( many type depending of the country, SECAM, both are 7 or 8 MHz wide. A system can carry many 6 MHz wide channel (as much as 110 TV channel, it can also transport 6 MHz wide QAM signal (digital form of NTSC signal, one 6 MHz wide can carry as much as 12 ch. in one QAM signal). This broadband system in North America utized two type of transmission system, fiber optic for the long distance (between the communications center and a OPTICAL NODE) and coaxial cable for the distribution at each customer on the system.
The retrun section is from all the customer to the HEADEND (5 to 40 MHz in North America) 5 to 65 MHz in Europe)
Below is a HFC system from the node to the customer.
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