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elitefx

join:2011-02-14
London, ON
kudos:2

1 edit

Docsis 3 vs Docsis 2 Operating Frequency

What frequency range does Docsis 3 run at? Is it higher or lower than Docsis 2? I've read digital signals run from 5MHZ to 2.4GHZ. Where on the frequency spectrum does Docsis 3 operate?
What frequency range do digital cable channels occupy? Rogers claims that their digital cable and internet use separate pipelines so to speak. Is this true?

scubascythan

join:2005-05-14
It's basically the same frequency range of of up to 1Ghz.

Docsis 3.0 downstream spec starts from 108Mhz to 1.002Ghz. Upstream from 5Mhz to 85Mhz.

Docsis 2.0 downstream spec starts from 88Mhz to 860Mhz. Upstream from 5Mhz to 42Mhz.

Docsis 3.0 uses multi-channel bonding while 2.0 does not.

No Docsis modem for consumer use actually uses close to the full spectrum cause of analog+digital channels.

Docsis 3.0 physical layer specs, RF transmission range in section 5:
»www.cablelabs.com/specifications ··· 0121.pdf

Docsis 2.0 RF interface specs, RF transmission range in section 4:
»www.cablelabs.com/specifications ··· 0422.pdf

Cable TV and internet are not sharing frequency channels so they should not be interfering with each other.

Analog channels occupy from the 50Mhz up to 300 or 400Mhz range depending on how many your cable company provides. Digital TV channels 'usually' start operating on the 500Mhz channels up to 700Mhz, while cable internet usually operates the upper 700Mhz up to 900Mhz. Note the standard in North America for a channel is 6Mhz in width which allows one analog channel, or carries enough bandwidth for approximately 2 HD channels or 10 SD channels.

Sunfox

join:2003-12-14
Markham, ON
Well, according to my modem, Rogers downstream (8 channels) here in Markham is between 615 and 663MHz, while upstream (4 channels) is between 22 and 38MHz.


elitefx

join:2011-02-14
London, ON
kudos:2
reply to scubascythan
Thanks a million....

aereolis

join:2003-06-12
Brampton, ON
reply to elitefx
Rogers currently uses only up to 42mhz for upstream but at one point will probably change it to the higher end of 85mhz to allow for faster uploads (i suspect it's in planning phases already, and probably not very far off).
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