Cisco Systems UBR7225VXR RF Specifications, Channel Symbol Rate Raw Data Rate Nominal Data

A P P E N D I X B

RF Specifications

Information in the following tables is from the DOCSIS and EuroDOCSIS Radio Frequency Interface Specification, and should be considered minimum recommended performance criteria for reliable data transmission on cable networks. The full specification may be found at the CableLabs website (http://www.cablemodem.com), and additional Euro-DOCSIS information may be found at ComLabs website (http://www.tcomlabs.com).

•NCTA—“NCTA Recommended Practices for Measurements on Cable Television Systems, 2nd Edition”- National Cable Television Association, Washington DC, revised October 1993

•CableLabs1—“Two-Way Cable Television System Characterization,” Cable Television Laboratories, Inc., April 12, 1995

•CableLabs2—“Digital Transmission Characterization of Cable Television Systems,” Cable Television Laboratories, Inc., November, 1999

Note Raw data rate in Table B-1 and Table B-2 includes nominal data throughput plus overhead.

Table B-1	Downstream Channel Data Rates
		Channel	Symbol Rate,	Raw Data Rate,	Nominal Data
Modulation Format		Bandwidth, MHz	Msym/sec	Mbps	Rate, Mbps
QAM-64		6	5.056941	30.34	~27
QAM-256		6	5.360537	42.88	~38
QAM-64		8	6.952	41.71	~37
QAM-256		8	6.952	55.62	~50

Table B-2	Upstream Channel Data Rates
		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
160		0.20	0.32	~0.3	0.64	~0.6
320		0.40	0.64	~0.6	1.28	~1.2
640		0.80	1.28	~1.2	2.56	~2.3

Cisco uBR7225VXR Universal Broadband Router Hardware Installation Guide

OL-17309-02 B-1