Agilent Technologies 4395A - Page 227

Measuring
3
dB
Bandwidth Using
the Width
Function
Measuring
3
dB
Bandwidth
Using
the
Width
Function
1.
Do one
of the
following:
Reference P
oint K
eystrokes
Maximum
value
Press
4
Sea
rch
5
N
N
N
N
N
N
N
N
NN
N
MAX
.
Nominal frequency
Press
4
Mark
er
5 and
enter
the
nominal
frequency
through
the
numerical
keypad.
2.
Press
4
Ma
rker
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
1MODE
MENU
N
NN
N
N
N
N
N
N
N
N
N
N
N
1MKR
to
make
the
marker
a
reference
.
3.
Press
4
Sea
rch
5
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
NN
NN
NN
N
N
N
N
N
N
N
N
N
N
N
WIDTH
[OFF]
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
NN
NN
NN
N
N
N
N
N
N
N
N
N
N
N
WIDTH
VALUE
.
4.
Press
4
0
5
4
3
5
4
2
1
5
to
enter
0
3
dB
.
5.
T
oggle
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
WIDTH
on
OFF to
N
N
NN
NN
NN
NN
N
N
N
N
N
N
N
N
N
N
ON
off
.
As
shown
in
Figure
8-11
,
a
pair
of
sub-markers
appear
on
both
sides
of
the
reference marker
,
being
lowered
by
the
specied
number
of
levels;
also
, another
sub-maker is
displayed in
the
middle
between
the
two
sub-markers
.
The
bandwidth
(
BW ),
center frequency
of the
bandwidth
(
cent
),
Q
factor
(
Q
),
insertion
loss (
loss ),
and left
and right
hand
bandwidth
(
1L.F
and
1R.F
)
are
displayed
at
the
upper
right
corner
of
the
grid.
Figure
8-12
shows
a typical
example of
a
band
pass
lter
measurement
trace
and
describes
each
parameter
.
0
will
be
returned for
all
parameters
when
two
cuto
points
can
not
be
found.
P
arameter
Description
Bandwidth
(BW)
The
stimulus
width
between
two
cuto
points
(f
1
and
f
2
)
Center
frequency
of the
bandwidth
(cent)
The
center
point (f
cent
)
of
the two
cuto points
(f
1
and
f
2
)
Q
factor
(Q)
Q
=
p
f
1
2
f
2
B
W
Insertion
loss
(loss)
The abosolute
value of
the dierence
of the
maximum
value
within
a
specied
range
and
0dB
Left hand
bandwidth
(1L.F)
The stimulus
dierence between
the left
hand
cuto
point
(f
1
)
and the
center point
of a
specied
rnage
.
Right
hand
bandwidth
(1R.F)
The
stimulus
dierence
between
the
right
hand cuto
point (f
2
)
and
the
center
point
of
a
specied range
.
You can move the reference marker using the rotary knob
. When you enable
the width
function, the reference marker automatically turns into a tracking 1marker that allows you to
move the reference marker
.
For more information on the width function, see Appendix A.
Analyzing the Measurement Results 8-25