Upstream Rf Channel Transmission Characteristics; Appendix B Rf Specification - Cisco UBR7225VXR Hardware Installation Manual

Appendix B RF Specifications
Table B-3 DOCSIS 1.0 Assumed Downstream RF Channel Transmission Characteristics (continued)
Parameter
Seasonal and diurnal signal level variation
Maximum analog video carrier level at the cable modem
input, inclusive of above signal level variation
Lowest analog video carrier level at the cable modem input,
inclusive of above signal level variation
1. For measurements above the normal operating frequency band (except hum), impairments are referenced to the highest-frequency NTSC carrier level.
2. This presumes that the digital carrier is operated at analog peak carrier level. When the digital carrier is operated below the analog peak carrier level, the
carrier-to-noise ratio may be less.
3. Decibels relative to carrier, a common measurement in RF engineering to specify the power of a sideband in a modulated signal relative to the carrier in
decibels.
4. For hum measurements above the normal downstream operating frequency band, a continuous-wave carrier is sent at the test frequency at the same level
as the highest-frequency NTSC carrier.

Upstream RF Channel Transmission Characteristics

Transmission is from the cable modem output at the customer location to the headend. Measurement
methods are defined in NCTA or CableLabs2 documentation.
Table B-4 DOCSIS 1.0 Assumed Upstream RF Channel Transmission Characteristics
Parameter
Frequency range
Transit delay from the most distant cable modem to the
nearest cable modem or CMTS
Carrier-to-noise ratio
Carrier-to-ingress power (the sum of discrete and broadband
ingress signals) ratio
Carrier-to-interference (the sum of noise, distortion,
common-path distortion, and cross-modulation) ratio
Carrier hum modulation
Burst noise
Amplitude ripple
Group delay ripple
Micro-reflections—single echo
Seasonal and diurnal signal level variation
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. (CableLabs1)
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).
OL-17309-01
Value
8 dB
17 dBmV
–5 dBmV
Value
5 to 42 MHz edge to edge
≤ 0.800 msec (typically much less)
Not less than 25 dB
Not less than 25 dB
Not less than 25 dB
Not greater than –23 dBc (7%)
Not longer than 10 μsec at a 1-kHz average rate for most
2, 3
cases
5 to 42 MHz: 0.5 dB/MHz
5 to 42 MHz: 200 ns/MHz
–10 dBc @ ≤ 0.5 microseconds
–20 dBc @ ≤ 1.0 microseconds
–30 dBc @ > 1.0 microseconds
Not greater than 8 dB min to max
Cisco uBR7225VXR Universal Broadband Router Hardware Installation Guide
DOCSIS 1.0 Transmission Characteristics
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B-3