Appendix B RF Specifications

EuroDOCSIS Transmission Characteristics

3.For hum measurements above the normal downstream operating frequency band, a continuous-wave carrier is sent to the test frequency at the same level as the highest-frequency PAL/SECAM carrier.

Upstream RF Channel Transmission Characteristics

Transmission is from the cable modem output at the customer location to the headend.

Table B-8

EuroDOCSIS Assumed Upstream RF Channel Transmission Characteristics

 

 

 

Parameter

 

Value

 

 

 

Frequency range

 

5 up to 65 MHz to edge

 

 

Transit delay from the most distant cable modem to the

0.800 msec (typically much less)

nearest cable modem or cable modem termination system

 

 

 

Carrier-to-noise ratio in active channel

Not less than 22 dB

 

 

Carrier-to-ingress power (the sum of discrete and broadband

Not less than 22 dB1

ingress signals) ratio in active channel

 

 

 

Carrier-to-interference (the sum of noise, distortion,

Not less than 22 dB

common-path distortion, and cross-modulation) ratio in

 

active channel

 

 

 

 

Carrier hum modulation

Not greater than –23 dBc (7%)

 

 

 

Burst noise

 

Not longer than 10 microseconds at a 1 kHz average rate for

 

 

most cases2, 3

Amplitude ripple

5 to 65 MHz: 2.5 dB in 2 MHz

 

 

Group delay ripple

5 to 65 MHz: 300 ns in 2 MHz

 

 

Micro-reflections—single echo

–10 dBc @ 0.5 microseconds

 

 

–20 dBc @ 1.0 microseconds

 

 

–30 dBc @ > 1.0 microseconds

 

 

Seasonal and diurnal signal level variation

Not greater than 12 dB min to max

 

 

 

1.Ingress avoidance or tolerance techniques may be used to ensure operation in the presence of time varying discrete ingress signals that could be as high as 0 dBc.

2.Amplitude and frequency characteristics sufficiently strong to partially or wholly mask the data carrier.

3.Impulse noise levels more prevalent at lower frequencies (<15 MHz).

Cisco uBR7225VXR Universal Broadband Router Hardware Installation Guide

 

OL-17309-02

B-7

 

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Cisco Systems UBR7225VXR specifications Upstream RF Channel Transmission Characteristics