Minimum Settings2 Your Headend Settings

Appendix A System Specifications

EuroDOCSIS Upstream and Downstream Specifications

Table A-6 DOCSIS Cable Downstream RF Specifications (continued)

Specification	DOCSIS Specifications1	Minimum Settings2	Your Headend Settings
Signal level slope (50 to 750 MHz)	16 dB	16 dB

Maximum analog video carrier level	+17 dBmV	+17 dBmV
(at CM)

Minimum analog video carrier level	–5 dBmV	–5 dBmV
(at CM)

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.

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-7and Table A-8.

Table A-7 EuroDOCSIS Cable Upstream RF Specifications

Specification	EuroDOCSIS Specifications1	Minimum Settings2	Your Headend Settings
System/Channel

Frequency range	5 to 65 MHz	5 to 65 MHz

Transit delay, CMTS to	< 0.800 ms	< 0.800 ms
furthest customer

Carrier to noise ratio	> 25 dB (QPSK3)4	> 21 dB (QPSK)4
	> 25 dB (16 QAM5)4	> 24 dB (16 QAM)4
Carrier to ingress power ratio	> 25 dB	> 25 dB

Carrier to interference ratio	> 25 dB (QPSK)4	> 21 dB (QPSK)4
	> 25 dB (16 QAM)4	> 24 dB (16 QAM)4
Carrier hum modulation	< –23 dBc6 (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

Cisco uBR7100 Series and Cisco uBR7100E Series Universal Broadband Router Hardware Installation Guide


OL-5916-01				A-5
OL-5916-01				A-5