Cisco Systems UBR7225VXR specifications

Chapter 4 Connecting the Cisco uBR7225VXR Router to the Cable Headend

Measuring the Downstream RF Signal

Figure 4-8 Measuring the RF Signal at the Upconverter Output—Overload Condition Corrected with Attenuation

Step 7 Change the spectrum analyzer settings to view the digital channel power. This setting enables you to see if there is too much power on the upconverter output. In Figure 4-9, the upconverter output is reading +64.31 dBmV, which is beyond the DOCSIS-specified range of +50 to +61 dBmV.

Tip A spectrum analyzer might become overloaded and produce false readings (such as internally generated spurs) when measuring a signal at this amplitude.

Figure 4-9 Measuring the RF Signal at the Upconverter Output—Upconverter Output Level Too High

Step 8 Adjust the power on the upconverter output to ensure that it is between +50 and +61 dBmV. In Figure 4-10, the upconverter output is reading +57.06 dBmV, which is within the correct range.

Cisco uBR7225VXR Universal Broadband Router Hardware Installation Guide

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