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EuroDOCSIS Upstream and Downstream Specifications
Table A-7
EuroDOCSIS Cable Upstream RF Specifications (continued)
Specification
Micro reflections (single echo) –10 dBc @ < 0.5 ms
Seasonal/diurnal signal level
variation
Carrier to second order
Digital Signal Levels
From cable modem (upstream) +8 to +58 dBmV (QPSK)
Input amplitude to modem
card (upstream)
Signal as relative to adjacent
video signal
1. EuroDOCSIS specifications are baseline settings for a EuroDOCSIS-compliant, two-way cable system.
2. Minimum settings are slightly different than the EuroDOCSIS settings to account for cable system variations over time and temperature. Using these
settings should increase the reliability of EuroDOCSIS-based, two-way cable systems.
3. QPSK = Quadrature Phase-Shift Keying: a method of modulating digital signals onto a radio-frequency carrier signal using four phase states to code
two digital bits.
4. These settings are measured relative to the digital carrier. Add 6 or 10 dB, as determined by your company's policy and derived from the initial cable
network setup, relative to the analog video signal.
5. QAM = Quadrature Amplitude Modulation: a method of modulating digital signals onto a radio-frequency carrier signal involving both amplitude and
phase coding.
6. dBc = decibels relative to carrier.
Table A-8
EuroDOCSIS Cable Downstream RF Specifications
Specification
System/Channel
RF channel spacing (bandwidth)
3
Transit delay
Carrier to noise ratio
Carrier to ingress power ratio
Composite triple beat distortion
Carrier to second order
Cross-modulation level
Amplitude ripple
Group delay
Micro reflections bound for dominant
echo
Carrier hum modulation
Cisco uBR7100 Series and Cisco uBR7100E Series Universal Broadband Router Hardware Installation Guide
A-6
EuroDOCSIS Specifications
–20 dBc @ < 1.0 ms
< 8 dB
< –50 dBc
+8 to +55 dBmV (16 QAM)
–10 to +25 dBmV
–6 to –10 dBc
EuroDOCSIS Specifications
8 MHz
0.800 ms
> 28 dB (64 QAM
> 33.5 dB (256 QAM)
> 35 dB
6
< –50 dBc
< –50 dBc
< –40 dBc
0.5 dB in 8 MHz
7
75 ns
in 8 MHz
–10 dBc @ < 0.5 ms
–15 dBc @ < 1.0 ms
–20 dBc @ < 1.5 ms
–30 dBc @ < 1.5 ms
< –26 dBc (5%)
1
2
Minimum Settings
–10 dBc @ < 0.5 ms
–20 dBc @ < 1.0 ms
< 8 dB
< –50 dBc
+8 to +58 dBmV (QPSK)
+8 to +55 dBmV (16 QAM)
–10 to +25 dBmV
–6 to –10 dBc
1
Minimum Settings
8 MHz
0.800 ms
4
5
)
> 28 dB (64 QAM)
5
> 31.5 dB (256 QAM)
> 35 dB
< –50 dBc
< –50 dBc
< –40 dBc
0.5 dB in 8 MHz
75 ns in 8 MHz
–10 dBc @ < 0.5 ms
–15 dBc @ < 1.0 ms
–20 dBc @ < 1.5 ms
–30 dBc @ < 1.5 ms
< –26 dBc (5%)
Appendix A
System Specifications
Your Headend Settings
2
Your Headend Settings
5
5
OL-5916-01
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Troubleshooting
