Agilent Technologies 35670A User Manual

To measure phase distortion
1 Complete either the FFT or the swept sine version of the task, “To measure frequency
response.”
2 Activate the trace you will use to measure phase distortion.
3 Press [
Trace Coord
][
MORE CHOICES
][
GROUP DELAY
].
4 Press [
DELAY APERTURE
] <number> [
ENTER
].
5 Press [
Scale
], then press [
AUTOSCALE ON OFF
] to highlight ON.
Group delay is the derivative (or slope) of the phase response. This makes it useful for
measuring a device’s phase linearity. The formula for group delay is:
−
∆(ph )⁄360
∆(f )
‘’delta(ph)’’ is the phase difference (in degrees) of two frequencies separated by
delta(f). ‘’delta(f)’’ is the group-delay aperture (in Hz), which you enter—as a
percentage of the current span—under [
DELAY APERTURE
]. Larger apertures increase
the amount of trace smoothing.
Group-delay trace using a 0.25% aperture.
The same trace using a 2.5% aperture.
Agilent 35670A
Measuring Spectra and Networks Operator's Guide
4-14

Agilent Technologies 35670A Specifications

General

Brand	Agilent Technologies
Model	35670A
Category	Measuring Instruments
Language	English