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Cisco uBR7100 Series and Cisco uBR7100E Series Universal Broadband Router Hardware Installation Guide
OL-5916-01
Appendix A System Specifications
EuroDOCSIS Upstream and Downstream Specifications
EuroDOCSIS Upstream and Downstream Specifications
The recommended settings listed in the following tables are based on a hybrid fiber-coaxial cable (HFC)
network in which the digital signal is carried 10 dB below the adjacent analog video channel. If the
digital signal on your network is carried 6 dB below the adjacent analog video channel, add 4 dB to the
recommended settings in Table A-7 and Table A-8.
Signal level slope (50 to 750 MHz) 16 dB 16 dB
Maximum analog video carrier level
(at CM)
+17 dBmV +17 dBmV
Minimum analog video carrier level
(at CM)
–5 dBmV –5 dBmV
Digital Signal Levels
From headend –15 to +15 dBmV –15 to +15 dBmV
Signal as relative to adjacent video signal –6 or –10 dBc –6 or –10 dBc
1. DOCSIS specifications are baseline settings for an DOCSIS-compliant, two-way data-over-cable system.
2. Minimum settings are slightly different than the DOCSIS settings to account for cable system variations over time and temperature. Using these settings
should increase the reliability of DOCSIS-compliant, two-way data-over-cable systems.
3. Transit delay is defined as the “round trip” from the cable headend to the furthest customer and back.
4. QAM = Quadrature Amplitude Modulation: a method of modulating digital signals onto a radio-frequency carrier signal involving both amplitude and
phase coding.
5. 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.
6. dBc = decibels relative to carrier.
7. ns = nanoseconds.
Table A-6 DOCSIS Cable Downstream RF Specifications (continued)
Specification DOCSIS Specifications
1
Minimum Settings
2
Your Headend Settings
Table A-7 EuroDOCSIS Cable Upstream RF Specifications
Specification EuroDOCSIS Specifications
1
Minimum Settings
2
Your Headend Settings
System/Channel
Frequency range 5 to 65 MHz 5 to 65 MHz
Transit delay, CMTS to
furthest customer
< 0.800 ms < 0.800 ms
Carrier to noise ratio > 25 dB (QPSK
3
)
4
> 25 dB (16 QAM
5
)
4
> 21 dB (QPSK)
4
> 24 dB (16 QAM)
4
Carrier to ingress power ratio > 25 dB > 25 dB
Carrier to interference ratio > 25 dB (QPSK)
4
> 25 dB (16 QAM)
4
> 21 dB (QPSK)
4
> 24 dB (16 QAM)
4
Carrier hum modulation < –23 dBc
6
(7%) < –23 dBc (7%)
Burst noise < 10 ms < 10 ms
Amplitude ripple 0.5 dB/MHz 0.5 dB/MHz
Group delay ripple 200 ns/MHz 200 ns/MHz