Cisco Systems UBR7100E manual Table A-8 EuroDOCSIS Cable Downstream RF Specifications

Appendix A System Specifications

EuroDOCSIS Upstream and Downstream Specifications

Table A-7 EuroDOCSIS Cable Upstream RF Specifications (continued)

Specification	EuroDOCSIS Specifications1	Minimum Settings2	Your Headend Settings
Micro reflections (single echo)	–10 dBc @ < 0.5 ms	–10 dBc @ < 0.5 ms
	–20 dBc @ < 1.0 ms	–20 dBc @ < 1.0 ms
Seasonal/diurnal signal level	< 8 dB	< 8 dB
variation
Carrier to second order	< –50 dBc	< –50 dBc
Digital Signal Levels
From cable modem (upstream)	+8 to +58 dBmV (QPSK)	+8 to +58 dBmV (QPSK)
	+8 to +55 dBmV (16 QAM)	+8 to +55 dBmV (16 QAM)
Input amplitude to modem	–10 to +25 dBmV	–10 to +25 dBmV
card (upstream)
Signal as relative to adjacent	–6 to –10 dBc	–6 to –10 dBc
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		EuroDOCSIS Specifications1	Minimum Settings2	Your Headend Settings
System/Channel
RF channel spacing (bandwidth)		8 MHz	8 MHz
Transit delay3		0.800 ms	0.800 ms
Carrier to noise ratio		> 28 dB (64 QAM4)5	> 28 dB (64 QAM)5
		> 33.5 dB (256 QAM)5	> 31.5 dB (256 QAM)5
Carrier to ingress power ratio		> 35 dB	> 35 dB
Composite triple beat distortion		< –50 dBc6	< –50 dBc
Carrier to second order		< –50 dBc	< –50 dBc
Cross-modulation level		< –40 dBc	< –40 dBc
Amplitude ripple		0.5 dB in 8 MHz	0.5 dB in 8 MHz
Group delay		75 ns7 in 8 MHz	75 ns in 8 MHz
Micro reflections bound for dominant		–10 dBc @ < 0.5 ms	–10 dBc @ < 0.5 ms
echo		–15 dBc @ < 1.0 ms	–15 dBc @ < 1.0 ms
		–20 dBc @ < 1.5 ms	–20 dBc @ < 1.5 ms
		–30 dBc @ < 1.5 ms	–30 dBc @ < 1.5 ms
Carrier hum modulation		< –26 dBc (5%)	< –26 dBc (5%)
	Cisco uBR7100 Series and Cisco uBR7100E Series Universal Broadband Router Hardware Installation Guide
A-6				OL-5916-01