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Appendix A
System Specifications
Table A-6
DOCSIS Cable Downstream RF Specifications (continued)
Specification
Signal level slope (50 to 750 MHz)
Maximum analog video carrier level
(at CM)
Minimum analog video carrier level
(at CM)
Digital Signal Levels
From headend
Signal as relative to adjacent video signal –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.
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
EuroDOCSIS Cable Upstream RF Specifications
Specification
System/Channel
Frequency range
Transit delay, CMTS to
furthest customer
Carrier to noise ratio
Carrier to ingress power ratio
Carrier to interference ratio
Carrier hum modulation
Burst noise
Amplitude ripple
Group delay ripple
OL-5916-01
DOCSIS Specifications
16 dB
+17 dBmV
–5 dBmV
–15 to +15 dBmV
Table A-7
EuroDOCSIS Specifications
5 to 65 MHz
< 0.800 ms
3
4
> 25 dB (QPSK
)
5
4
> 25 dB (16 QAM
)
> 25 dB
4
> 25 dB (QPSK)
4
> 25 dB (16 QAM)
6
< –23 dBc
(7%)
< 10 ms
0.5 dB/MHz
200 ns/MHz
Cisco uBR7100 Series and Cisco uBR7100E Series Universal Broadband Router Hardware Installation Guide
EuroDOCSIS Upstream and Downstream Specifications
1
Minimum Settings
16 dB
+17 dBmV
–5 dBmV
–15 to +15 dBmV
–6 or –10 dBc
and
Table
A-8.
1
2
Minimum Settings
5 to 65 MHz
< 0.800 ms
4
> 21 dB (QPSK)
4
> 24 dB (16 QAM)
> 25 dB
4
> 21 dB (QPSK)
4
> 24 dB (16 QAM)
< –23 dBc (7%)
< 10 ms
0.5 dB/MHz
200 ns/MHz
2
Your Headend Settings
Your Headend Settings
A-5
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