
Time
Domain
Antenna
Transmission
Measurements
Figure
13-13.
Responses
in
a
Typical
RCS
Range
When
using
Time
Domain
to
distinguish
between
main
path
responses
and
ground
path
responses
,
the
path
dierence
delta
must
be
greater
than
the
impulse
response
of
the
antenna
under
test.
In
general,
broadband
antennas
have
shorter
duration
transmission
Time
Domain
impulse
responses
.
It
is
recommended
that
the
antenna
be
characterized
only
over
its
operational
bandwidth.
Measuring
an
antenna
outside
of
its
bandwidth
will
not
reduce
its
impulse
response
width,
and
it
may
adversely
aect
the
Time
Domain
measurement.
Antenna
Transmission
Alias-Free
Range
and
Aliasing
Time
Domain
transmission
response
measurements
also
have
an
Alias-Free
Range
that
is
equal
to
1/1F
,
where
1F
is
the
spacing
between
Frequency
Domain
data
points
(the
same
as
for
RCS
measurements).
Usually
,
aliasing
is
much
less
limiting
for
antenna
transmission
measurements
than
for
RCS
measurements
.
It
is
recommended
that
the
Alias-Free
Range
of
the
measurement
be
less
than
the
greatest
dierence
between
the
line-of-sight
path
and
multi-path
signals
.
Note
that
this
dierence
is
usually
far
less
than
the
actual
length
of
the
antenna
test
range
.
T
o
increase
the
Alias-Free
Range
,
rst
increase
the
Number
of
P
oints
measured
in
the
Frequency
Domain.
If
going
to
the
maximum
Number
of
P
oints
(801)
is
not
sucient,
then
you
must
reduce
the
Frequency
Domain
span.
Since
this
reduces
the
Time
Domain
resolution,
it
is
recommended
that
you
keep
the
frequency
span
as
wide
as
possible
(within
the
operating
bandwidth
of
the
test
antenna).
Eects
of
Antenna
Calibration
The
purpose
of
antenna
gain
calibration
is
to
calibrate
the
antenna
transmission
response
in
dBi
(relative
to
an
isotropic
radiator).
Although
the
intention
is
to
reduce
the
eect
of
all
test
range
measurement
errors
,
the
only
error
terms
that
can
be
characterized
are
the
receiver
isolation
(crosstalk)
and
the
range/receiver
frequency
response
.
A
2-term
error
model
is
used.
However
,
this
does
not
remove
the
eects
of
multipath.
The
frequency
response
error
term
is
characterized
by
measuring
a
standard
gain
antenna.
Before
calibration
is
turned
ON,
the
location
(in
time)
of
the
antenna
transmission
response
is
determined
by
the
dierence
between
the
line-of-site
transmission
path
and
the
reference
13-22
Introduction
to
Time
Domain
RCS
and
Antenna
Measurements
Содержание 8530A
Страница 9: ......
Страница 31: ......
Страница 34: ...General Information Figure 1 2 Antenna Measurement Setup Using an HP 85310A GeneralInformation 1 3 ...
Страница 51: ......
Страница 65: ......
Страница 81: ......
Страница 83: ......
Страница 84: ...5 Menus Block Chapter Contents Calibration Domain Display Markers MenusBlock 5 1 ...
Страница 85: ...5 2 Menus Block ...
Страница 90: ...Calibration Requirements Figure 5 1 Cal and Cal Type Menus MenusBlock 5 7 ...
Страница 93: ...Antenna Calibration 5 10 MenusBlock ...
Страница 167: ......
Страница 195: ......
Страница 201: ......
Страница 209: ......
Страница 249: ......
Страница 281: ......
Страница 411: ......
Страница 419: ...Glossary Glossary 8 ...
Страница 439: ......