Docsis 1.0 Transmission Characteristics; Downstream Rf Channel Transmission Characteristics - Cisco UBR7225VXR Hardware Installation Manual

DOCSIS 1.0 Transmission Characteristics

Table B-2
Symbol Rate,
ksym/sec
1280
2560
DOCSIS 1.0 Transmission Characteristics
The following tables provide information on the assumed downstream RF channel transmission
characteristics for DOCSIS 1.0.

Downstream RF Channel Transmission Characteristics

Transmission is from the headend combiner to the cable modem input at the customer location.
Measurement methods are defined in NCTA or CableLabs2 documentation.
Go to the following URL: http://www.ncta.com/. Search on "transmission".
Go to the following URL:
Table B-3 DOCSIS 1.0 Assumed Downstream RF Channel Transmission Characteristics
Parameter
1
Frequency range
RF channel spacing (design bandwidth)
Transit delay from headend to most distant customer
Carrier-to-noise ratio in a 6-MHz band (analog video level)
Carrier-to-interference ratio for total power (discrete and
broadband ingress signals)
Composite triple beat distortion for analog modulated carriers Not greater than –50 dBc
Composite second-order distortion for analog modulated
carriers
Cross-modulation level
Amplitude ripple
Group delay ripple in the spectrum occupied by the CMTS
Micro-reflections bound for dominant echo
4
Carrier hum modulation
Burst noise
Signal level slope, 50-750 MHz
Cisco uBR7225VXR Universal Broadband Router Hardware Installation Guide
B-2
Upstream Channel Data Rates (continued)
Channel QPSK Raw
Bandwidth, Data Rate,
MHz Mbps
1.60 2.56
3.20 5.12
http://www.cablelabs.com/.
Value
Cable system normal downstream operating range is from 50
MHz to as high as 860 MHz. However, the values in this table
apply only at frequencies ≥ 88 MHz.
6 MHz
Not less than 35 dB
Not less than 35 dB within the design bandwidth
Not greater than –50 dBc within the design bandwidth
Not greater than –40 dBc within the design bandwidth
0.5 dB within the design bandwidth
75 ns within the design bandwidth
–10 dBc @ ≤ 0.5 microseconds
–15 dBc @ ≤ 1.0 microseconds
–20 dBc @ ≤ 1.5 microseconds
–30 dBc @ >1.5 microseconds
Not greater than –26 dBc (5%)
Not longer than 25 μsec at a 10-Hz average rate
16 dB
QPSK Nominal
Data Rate,
Mbps
~2.3
~4.6
≤ 0.800 msec (typically much less)
2
3
within the design bandwidth
Appendix B RF Specifications
QAM-16 Raw QAM-16
Data Rate, Nominal Data
Mbps Rate, Mbps
5.12 ~4.6
10.24 ~9.0
OL-17309-01