HP 8591C User Manual page 63

Channel Measurements
Making Channel Measurements
Note that when an external preamplifier is used and EXT AMP YES NO is
activated (YES is underlined), the noise contribution of the preampliEer
is also calculated and corrected for. The values for external preamplifier
gain and noise figure are used for this calculation. This is the only use
made of the values entered with the external preamplifier softkeys
(EXT AMP YES NO , EXT AMP GAIN , or EXT AMP NZ FIG ).
Hints
1. When using a tunable bandpass filter, first peak the filter using
press
CARRIER/NOISE
the carrier to minimize any roll-off effect of the bandpass filter.
2. Pressing GO
TO CSO/CTB
modulation back on, then off again [for analyzers without Option 1071, or to reselect a quiet line
3. Carrier-to-Noise Measurement Accuracy is degraded as the
analyzer noise. This is reflected in the magnitude of the Analyzer Noise Correction Value.
analyzer noise correction value.
if less than 0.5 dB, then C/N accuracy fl dB
if equal to 0.5 dB, then C/N accuracy 411.25 dB
if equal to 3 dB, then C/N accuracy &2 dB
if equal to 7 dB, then C/N accuracy 4~3.5 dB
if greater than 7 dB it is out of measurement range
5. The analyzer input attenuator sets the noise floor of the analyzer. The attenuator is set to not
overload the first mixer. For carrier to noise, the attenuator switch point from 0 to 10 dB is at
2-20
Place the marker to measure the carrier-to.-noise close enough to
allows you to measure the CSOKTH without having to turn the
cable
More, then
MORE INFO
Then
CARRIER LVL&FRCj
TV system noise approaches the
Note the