Agilent Technologies 8719ES User Manual page 61

The default aperture is the total frequency span divided by the number of points across the
display (i.e. 201 points or 0.5% of the total span in this example).
1. Continue with the same instrument settings and measurements as in the previous
procedure, "Deviation From Linear Phase."
2. To view the measurement in delay format, as shown in
DELAY
Format
3. To activate a marker to measure the group delay at a particular frequency, press
and turn the front panel knob, or enter a value from the front panel keypad.
Marker
Figure 1-37 Group Delay Example Measurement
Group delay measurements may require a specific aperture (∆)F) or frequency spacing
between measurement points. The phase shift between two adjacent frequency points
must be less than 180°, otherwise incorrect group delay information may result.
4. To vary the effective group delay aperture from minimum aperture (no smoothing) to
approximately 1% of the frequency span, press:
When you increase the aperture, the analyzer removes fine grain variations from the
response. It is critical that you specify the group delay aperture when you compare
group delay measurements.
SCALE DIV
Scale Ref
Measuring Electrical Length and Phase Distortion
Figure 1-37, press:
SMOOTHING ON
Avg
Making Measurements
.
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