To Change System Bandwidth For Reducing Trace Noise - HP 8711C User Manual

Optimizing Measurements
Reducing Trace Noise
By reducing the system bandwidth you reduce the noise that is measured
during the sweep. However, the decreased bandwidth may slow down the
sweep. While averaging requires multiple sweeps to reduce noise, narrowing
the system bandwidth reduces the noise on each sweep. See the previous
section for a more detailed explanation of system bandwidth.
Press (AVG) Systam Bandwidth lkwxw or F&ne .
Narrower system bandwidths cause longer sweep times. When in auto sweep
time mode, the analyzer uses the fastest sweep time possible for any selected
system bandwidth. Auto sweep time mode is the default analyzer setting.
Spurious responses are undesirable signals that result from various internal
mixing products.
The analyzer has two features to eliminate spurious responses. Both features
shift the frequency of the spur without changing the RF output frequency.
They shift the spur by changing frequencies internal to the analyzer that mix
to produce the RF frequency. The features are:
dither
l
Dither is usually most effective for narrow frequency span measurements
(generally ~15 MHz) as explained below. If dither does not eliminate visible
spurs, use spur avoid instead.
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