HP 8753D - Page 160

Figure
3-27.
Example
Mixer
LO to
RF Isolation
Measurement
RF
F
eedthrough
The
procedure
and
equipment
conguration
necessary
for
this
measurement
are very
similar
to
those
above
,
with
the
addition
of
an
external source
to drive
the mixer's
LO port
as
we
measure
the mixer's
RF feedthrough.
RF feedthrough
measurements do
not
use
the
frequency
oset
mode
.
1.
Select
the
CW LO
frequency and
source
power
from
the
front
panel
of
the
external
source
.
CW
frequency
=
300
MHz
P
ower
=
10
dBm
2.
Initialize
the
analyzer
by
pressing
4
PRESET
5
.
3.
T
o
select
the
analyzer's
frequency
range
and
source
power
,
press:
4
ST
ART
5
4
10
5
4
M/

5
4
STOP
5
4
3000
5
4
M/

5
4
MENU
5
N
N
N
N
N
N
NN
NN
NN
NN
N
N
N
POWER
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
PWR
RANGE
MAN 4
0
5
4
x1
5
This
signal
stimulates
the mixer's
RF port.
4.
To
select
a
ratio
measurement,
press:
4
MEAS
5
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
INPUT
PORTS
N
N
N
N
N
N
N
N
N
N
N
B/R
Note
Isolation is dependent on LO power level and frequency
.T
o
ensure good
test results
, you should choose these parameters as close to actual operating
conditions as possible
.
5.
Make the connections as shown in Figure 3-28.
Making Mixer Measurements 3-35