02-09-2012, 03:25 PM
For those asking what the correct levels are..
Here are the specs for the Motorola SB 51XX modems
Motorola SB51XX SURFboard DOCSIS 2.0 Cable Modem
General Features:
USB and 10/100Base-T Ethernet
F-connector, female, 75 ohm coaxial input
Data protocol: TCP/IP
Energy Star certified power adapter
Lead-free components (RoHS compliant)
Downstream:
Modulation: 64 or 256 QAM
Maximum Data Rate: DOCSIS < 38 Mbps
Bandwidth: 6 MHz
Symbol rate: 64 QAM 5.057 Msym/s, 256 QAM 5.361 Msym/s
Operating Level Range: -15 to +15 dBmV
Input impedance: 75 ohm
Upstream:
Modulation: 8, 16, 32, 64, 128 QAM or QPSK
Maximum Channel Rate: 30 Mbps
Bandwidth: 200 kHz, 400 kHz, 800 kHz, 1.6 MHz, 3.2 MHz, 6.4 MHz
Symbol rates: 160, 320, 640, 1280, 2560, 5120 ksym/s
Operating Level Range:
A-TDMA: +8 to +54 dBmV (32 QAM, 64 QAM), +8 to +55 dBmV (8 QAM, 16 QAM),
S-CDMA: +5 to +58 dBmV (QPSK), +8 to 53 dBmV (all modulations)
Output Impedance: 75 ohms
Frequency range: DOCSIS 5 to 42 MHz (edge to edge)
Here are the specs for the Motorola SB 51XX modems
Motorola SB51XX SURFboard DOCSIS 2.0 Cable Modem
General Features:
USB and 10/100Base-T Ethernet
F-connector, female, 75 ohm coaxial input
Data protocol: TCP/IP
Energy Star certified power adapter
Lead-free components (RoHS compliant)
Downstream:
Modulation: 64 or 256 QAM
Maximum Data Rate: DOCSIS < 38 Mbps
Bandwidth: 6 MHz
Symbol rate: 64 QAM 5.057 Msym/s, 256 QAM 5.361 Msym/s
Operating Level Range: -15 to +15 dBmV
Input impedance: 75 ohm
Upstream:
Modulation: 8, 16, 32, 64, 128 QAM or QPSK
Maximum Channel Rate: 30 Mbps
Bandwidth: 200 kHz, 400 kHz, 800 kHz, 1.6 MHz, 3.2 MHz, 6.4 MHz
Symbol rates: 160, 320, 640, 1280, 2560, 5120 ksym/s
Operating Level Range:
A-TDMA: +8 to +54 dBmV (32 QAM, 64 QAM), +8 to +55 dBmV (8 QAM, 16 QAM),
S-CDMA: +5 to +58 dBmV (QPSK), +8 to 53 dBmV (all modulations)
Output Impedance: 75 ohms
Frequency range: DOCSIS 5 to 42 MHz (edge to edge)