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Cisco uBR7200 Series Universal Broadband Router Hardware Installation Guide
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Chapter 4 Connecting the Cisco uBR7200 Series Router to the Cable Headend
Connecting and Configuring the Downstream
Step 1
Connect a spectrum analyzer to the downstream connector on a Cisco cable interface card installed in a
Cisco uBR7200 series universal broadband router.
Step 2
Turn the power switch on the spectrum analyzer to the ON position.
Step 3
Set the spectrum analyzer to view the downstream intermediate frequency (IF) signal with a center
frequency of 44 MHz for a North American headend or 36.125 MHz for a European headend.
Step 4
Set the resolution bandwidth to 100 kHz, the video bandwidth to 1 MHz, the span to 12 MHz, and the
sweep time to 20 msec. Your analyzer should display a signal similar to the one shown in
Figure 4-7
.
Figure 4-7
Downstream IF Channel Power
Step 5
Stop downstream digital data transmission from the cable interface card by setting the downstream
symbol rate to 0 on your downstream cable interface. This transmits an unmodulated IF carrier signal
over the downstream. To accomplish this, enter the following Cisco IOS command in interface
configuration mode:
Router(config-if)# cable downstream symbol 0
Your analyzer should display a signal similar to the one shown in
Figure 4-8
.
Содержание 7246 - uBR Router
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