HP 8591C User Manual page 113

System Measurements
Making System Measurements
5. Fix- using an external ampli$er @weamp): An external amplifier may be
required for the carrier-to-noise test. See Chapter 8 for more information
about when a preamplifier is required for the carrier-to-noise test. The
carrier-to-noise test calculates the noise contribution of the external
amplifier and reports that correction on the MORE INFO screen of the
carrier-to-noise test.
Connect the output of the external amplifier to the analyzer input (or
l
input of coupler).
Connect the cable TV signal to the input of the external amplifier.
l
Press Analyzer Input EXT AMP YES NO to underline YES.
l
Press EXT AMP GAIN then enter the gain value of the external
l
amplifier. The default value is 20 dB for the HP 85905A preampliEer.
Press EXT AMP NZ FIG then enter the noise figure value of the
l
external amplifier. The default value is 7 dB for the HP 85905A
preamplifier.
Press Prev Menu to return to the Setup menu.
l
The TOTL PWR Q INPUT function measures the total RF power into the
analyzer. Use this function to externally adjust the total power into the
analyzer or preamplifier for optimization of measurement dynamic range.
C E N T E R 5 7 . 8 8 8 M H z
RI :S BW
Figure 3-2. Analyzer Input Configuration Menu
3-6
30 kHz
T O T L P W R
S P A N fi.RBB RHz