Cisco Systems uBR7200 Series Setting Downstream Test Signals, Configure Unmodulated Test Signals

Chapter 4 Troubleshooting the System

Setting Downstream Test Signals

Table 4-28 Cable Upstream Freq-adj Averaging Syntax Descriptions

Syntax	Valid Values
n	Specifies the upstream port number.
averaging	Specifies that a percentage of frequency adjustment packets is
	required to change the adjustment method from the regular power
	adjustment method to the noise power adjustment method.

%of frequency adjustment Specifies the percentage of frequency adjustment packets required to switch from the regular power adjustment method to the noise power adjustment method. Valid range is from 10 through 100 percent.

The following example shows how to change the power adjustment method when the frequency adjustment packet count reaches 50 percent:

router(config-if)#cable upstream 0 freq-adj averaging 50

Setting Downstream Test Signals

This feature provides configuration commands that allow you to create downstream test signals. Both Pseudo Random Bit Stream (PRBS) and unmodulated carrier test signals are now supported.

A PRBS test signal is a random data pattern that has been modulated to look like a real data stream. An unmodulated test signal is a continuous sine wave that looks like a carrier wave on the downstream transmission.

See the following required tasks to create PRBS and unmodulated carrier test signals:

•Configure Unmodulated Test Signals

•Configure PRBS Test Signals

Configure Unmodulated Test Signals

Table 4-29 Instructions to Configure Unmodulated Test Signals

Step	Command	Purpose
1.	# router(config-if)#cable downstream if-output	Generates an unmodulated continuous-wave signal
	continuous-wave	on the downstream channel. The interface is shut
		down.
2.	Router(config-if)#no cable downstream if-output	Stops sending test signals.
		Note	Remember to reenable the
			interface to resume normal
			operations.

Cisco uBR7200 Series Universal Broadband Router Software Configuration Guide

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