HP 8591C User Manual

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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 CARRIER LVL&FRCj Then
press CARRIER/NOISE Place the marker to measure the carrier-to.-noise close enough to
the carrier to minimize any roll-off effect of the
bandpass filter.
2. Pressing GO
TO CSO/CTB allows you to measure the CSOKTH without having to turn the
modulation back on, then off again [for analyzers without Option 1071, or to reselect a quiet line
lfor analyzers with Option 107).
3. Carrier-to-Noise Measurement Accuracy is degraded as the cable TV system noise approaches the
analyzer noise. This is reflected in the magnitude of the Analyzer Noise Correction Value.
4. When in the carrier-to-noise measurement, press More, then MORE INFO Note the
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
+37 dBmV total power at the input.
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HP 8591C Specifications

General

Brand	HP
Model	8591C
Category	Measuring Instruments
Language	English