HP 8753D - Page 79

Measuring Electrical
Length and
Phase Distortion
Electrical
Length
The
analyzer
mathematically
implements
a
function
similar to
the mechanical
\line stretchers"
of
earlier
analyzers
.
This
feature
simulates a
variable length
lossless transmission
line,
which
you
can
add
to
or remove
from the
analyzer's receiver
input to
compensate
for
interconnecting
cables
,
etc
.
In this
example,
the electronic
line stretcher
measures
the
electrical
length
of
a
SA
W
lter
.
Phase
Distortion
The
analyzer
allows you
to measure
the linearity
of
the
phase
shift
through
a
device
over
a
range
of
frequencies and
the analyzer
can express
it in
two
dierent
ways:
deviation
from
linear phase
group
delay
Measuring
Electrical
Length
1.
Connect
your
test
device
as
shown
in
Figure
2-28
.
Figure
2-28.
Device
Connections
for
Measuring
Electrical
Length
2.
Press
4
PRESET
5
and
choose
the
measurement
settings
.
F
or
this
example,
the measurement
settings
include
reducing
the
frequency
span
to
eliminate
under
sampled
phase response
.
Press
the
following
keys
as
shown:
4
MEAS
5
N
NN
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
NN
NN
NN
NN
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
NN
NN
NN
NN
N
N
N
N
N
N
N
N
N
Trans:
FWD S21
(B/R)
4
CENTER
5
4
134
5
4
M/

5
4
SPAN
54
2
54
M/ 
5
4
MENU
5
NNNNNNNNNNNNNNNNN
POWER 4
5
54
x1
5
4
FORMAT
5
NN
NNNNNNNNNNNNNNN
PHASE
4
SCALE REF
5
NNNNNNNNNNNNNNNNNNNNN
NNNNNNNNNNN
AUTO SCALE
You may also want to select settings for the number of data points
, averaging, and IF
bandwidth.
2-30 Making Measurements