said by DocDrew:Cable ops would have to change out all the diplex filters in their gear to get more upstream spectrum, but then it would impede on the lower broadcast channels (channel 2 starts at 50 Mhz).
Yes, ARRIS demonstrated a "high-split DOCSIS upstream system" at the 2011 Cable show in Chicago: »
www.prnewswire.com/news- ··· 744.html"The demo will also show a proof-of-concept implementation of a 5-200 MHz high-split DOCSIS upstream system with 575 Mbps of DOCSIS upstream bandwidth being transmitted over 24 DOCSIS Upstream channels out of a single Fiber Node. This demo uses a single ARRIS 24U CAM to receive the high-split 5-200 MHz upstream spectrum from a Fiber Node. This record-breaking upstream bandwidth is intended to help the industry explore the future frequency allocations of HFC to protect its value and viability for many years to come."
I also found this item from a year ago on the CED Magazine website:
Cox, Motorola lay claim to new return path speed record
CED Magazine - March 1, 2011
»
www.cedmagazine.com/news ··· d-record"Using a Motorola DOCSIS 3.0 RX48 return path receiver module operating within a Motorola BSR 64000 cable modem termination system (CMTS) edge router, the record of 356 Mbps for a 5-85 MHz return path was set by transmitting across 12 return path channels, of which six channels employed 256 QAM modulation. Motorola said typical HFC networks today have two or three upstream channels delivering an aggregate of 40-70 Mbps.
:
In addition to establishing the world record at 5-85 MHz, a maximum transmission rate of 141 Mbps was also achieved over a 5-42 MHz return path using six return path channels. Three of these channels were able to operate using 256 QAM modulation, as opposed to 64 QAM maximum in use today, which is also believed to be a record.
Motorola said that for the first time, cable operators could use the 5-42 return path to provide 100 Mbps dedicated to business customers, while at the same time providing residential customers with the return path bandwidth necessary to meet their growing needs."