RF Requirements For A Reliable Zenith Network
Carrier/anything of at least 25 dB at the receive port of all modems. To support the time varying nature of an HFC network, 35 dB C/anything was required at the input to the frequency translator in the headend.
Carrier/anything is not a technical term, but is intended to include: C/Noise, C/Interference, and distortion products.
Downstream input to each cable modem of +5 dBmV +/- 2 dB. Due to the non-existence of any real input AGC, the lack of a re-modulating frequency translator, and lack of upstream transmit power control, the tight receive level range accommodated upstream path variation.
In comparison, a 2003 DOCSIS 2.0 compliant CMTS operating at 0.5 to 1 dB from theory will provide both 16QAM and 64 QAM in 6.4 MHz at 25 dB C/noise, and in some cases negative C/I. Next-Gen CMTSs
Read more about this topic: Zenith Cable Modem
Famous quotes containing the words reliable and/or network:
“When the water of a place is bad it is safest to drink none that has not been filtered through either the berry of a grape, or else a tub of malt. These are the most reliable filters yet invented.”
—Samuel Butler (1835–1902)
“Parents need all the help they can get. The strongest as well as the most fragile family requires a vital network of social supports.”
—Bernice Weissbourd (20th century)