Cisco Systems UBR7225VXR specifications Docsis 1.0 Transmission Characteristics, Parameter Value

Appendix B RF Specifications

DOCSIS 1.0 Transmission Characteristics

Table B-2	Upstream Channel Data Rates (continued)
		Channel	QPSK Raw	QPSK Nominal	QAM-16 Raw	QAM-16
Symbol Rate,		Bandwidth,	Data Rate,	Data Rate,	Data Rate,	Nominal Data
ksym/sec		MHz	Mbps	Mbps	Mbps	Rate, Mbps
1280		1.60	2.56	~2.3	5.12	~4.6
2560		3.20	5.12	~4.6	10.24	~9.0

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: http://www.cablelabs.com/.

Table B-3 DOCSIS 1.0 Assumed Downstream RF Channel Transmission Characteristics

Parameter		Value
Frequency range1		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.
RF channel spacing (design bandwidth)		6 MHz
Transit delay from headend to most distant customer		≤ 0.800 msec (typically much less)
Carrier-to-noise ratio in a 6-MHz band (analog video level)		Not less than 35 dB2
Carrier-to-interference ratio for total power (discrete and		Not less than 35 dB within the design bandwidth
broadband ingress signals)
Composite triple beat distortion for analog modulated carriers		Not greater than –50 dBc3 within the design bandwidth
Composite second-order distortion for analog modulated		Not greater than –50 dBc within the design bandwidth
carriers
Cross-modulation level		Not greater than –40 dBc within the design bandwidth
Amplitude ripple		0.5 dB within the design bandwidth
Group delay ripple in the spectrum occupied by the CMTS		75 ns within the design bandwidth
Micro-reflections bound for dominant echo		–10 dBc @ ≤ 0.5 microseconds
		–15 dBc @ ≤ 1.0 microseconds
		–20 dBc @ ≤ 1.5 microseconds
		–30 dBc @ >1.5 microseconds
Carrier hum modulation4		Not greater than –26 dBc (5%)
Burst noise		Not longer than 25 μsec at a 10-Hz average rate
Signal level slope, 50-750 MHz		16 dB
	Cisco uBR7225VXR Universal Broadband Router Hardware Installation Guide
B-2		OL-17309-02