Measuring Phase Distortion - Agilent Technologies 8719D User Manual

electrical length until you achieve the best flat line, as shown in Figure 2-35.
The measurement value that the analyzer displays represents the electrical length of your
device relative to the speed of light in free space. The physical
related to this value by the propagation velocity of its medium.
Velocity factor is the ratio of the velocity of wave propagation in a
Note
coaxial cable to the velocity of wave propagation in free space. Most
cables have a relative velocity of about 0.66 the speed in free space. This
velocity depends on the relative permittivity of the cable dielectric (cp) as
v e l o c i t y f a c t o r =
You could change the velocity factor to compensate for propagation velocity by
pressing Ical] $@I#& #&&%XiX FA@'IXJR (enter the value) (XJ This will help the
analyzer to accurately calculate the equivalent distance that corresponds to the
entered electrical delay.
Figure 2-35. Example Best Flat Line with Added Electrical Delay
9. 'lb display the electrical length, press:
In this example, there is a large amount of electrical delay due to the long electrical length
of the SAW lUer under test.

Measuring Phase Distortion

This portion of the example shows you how to measure the linearity of the phase shift over
a range of frequencies. The analyzer allows you to measure this linearity and read it in two
different ways: deviation from linear phase, or group delay.
.
of your device is
length
Making Measurements 238