4-21
Cisco uBR7200 Series Universal Broadband Router Hardware Installation Guide
OL-5421-03
Chapter 4 Connecting the Cisco uBR7200 Series Router to the Cable Headend
Measuring the Downstream RF Signal
Figure 4-20
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 4-21
, 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 4-21
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 b50 and +61 dBmV. In
Figure 4-22
, the upconverter output is r57.06 dBmV, which is within the correct range.
