Agilent Technologies Agilent 4396B - Manual (Page 97)

1F (commonly called the \aperture") is the frequency
dierence that gives 1
T o display group delay , press 4 F ormat 5
NNNNNNNNNNNNNNNNN
DELAY . If the trace needs to be
rescaled, press 4 Scale Ref 5 and
NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN
AUTO SCALE . The default aperture is
very narrow , so the group delay measurement displayed is very noisy .
Figure 5-10. Group Delay
Smoothing Group Delay Trace
By setting a wide aperture , rapid changes in phase are averaged
and have less aect on the measurement. However , some loss in
measurement detail occurs with wide apertures . Press 4 Bw/Avg 5
NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN
GROUP DELAY APERTURE . The value of the aperture is shown at
the upper left of the display . Press 4 * 5 to increase the aperture (the
display becomes less noisy).
Where to Find More Information
F or more information on group delay principles , see the T ask
R eference manual.
Network Measurement Examples 5-11