HP 8753D - Page 78

The
phase response
shown in
Figure 2-27
is
undersampled;
that
is
,
there
is
more
than
180

phase
delay between
frequency
points
.
If
the
1

=
>
180

,
incorrect phase
and
delay
information
may result.
Figure
2-27
shows
an
example
of
phase
samples
being
with
1
 less
than
180

and
greater than
180

.
Figure
2-27.
Phase
Samples
Undersampling
may
arise
when
measuring
devices
with
long electrical
length. T
o
correct
this
problem,
the
frequency
span
should
be
reduced,
or
the
number of
points
increased
until
1

is
less
than
180

per
point.
Electrical
delay
may
also
be
used
to
compensate for
this
eect
(as
shown
in
the
next
example
procedure).
Making Measurements 2-29