I'm new at telecommunications so this may be a simple question, but somehow I can't get my head around this. Can someone explain me in simple words how the terms DOCSIS and DVB-C are related? Both are "standards that define how to transmit data over HFC infrastructure", but what exactly defines DOCSIS and what DVB-C? Is DVB-C a standard for the signal and DOCSIS for the receiver?
DVB-C and DOCSIS coexist on the same medium using frequency-division multiplex (FDM). Each one uses a frequency band dedicated to it.
Basically, DOCSIS uses several DVB-C channels (6 or 8 MHz each, depending on whether DVB is using NTSC or PAL). Within the DOCSIS segment, time-division multiple access (TDMA) is used to separate downstream and upstream - in contrast to television broadcasting, a network connection needs to be bi-directional. Later DOCSIS versions added code-division multiple access (CDMA) to make better use of the spectrum.
As I understand it.
DVB-C is a standard for broadcasting digital TV over cable TV networks while DOCSIS is a standard for providing general purpose bidirectional data communications over cable TV networks. Both are likely to coexxist on the same cable infrastructure as most providers provide a mix of broadcast TV and "broadband" data service.
It seems that the European variants of Earlier versions of DOCSIS borrow the low level modulation techniques from DVB-C (with the american versions using an ITU standard), while the newever versions allow a broader range of modulation depths .