Racal Instruments 9081 Maintenance Manual page 90

(3)
Set the
Spectrum Analyser controls as follows:-
(4)
(5)
Input
attenuation
Log.
ref.
Vernier
Scanwidth
Video
filter
Bandwidth
30dB
+10dB
-7dB
0-1250MHz
on
red control,
Off
300kHz
Tune
the
UUT
from
240
to
540MHz
and, by observing
the
spectrum analyser,
verify that
all
harmonics
are at least
30dB below
carrier level,
and
that
sub-harmonically
related signals are at least
40dB below
carrier.
Tune
the
UUT
through
each
range
in
turn
and
verify that the
harmonics
and sub-harmonics meet
the
limits
in
Table
9.
The spectrum analyser
setting for
each range
are
given
in
Table 9.
TABLE
9
Distortion
Check
Tuning
Range
MHz
Analy
Centre
freq.
ser
Scanwidth
—
UUT
Harmonic
Sub-Harmonically
Level
Related
Signals
256-512
_
0- 1250MHz
)
128-256
500
MHz
lOOMHz/div)
At
least
At
least
64-128 500MHz
lOOMHz/div)
30dB
40db below
32-64 500MHz
lOOMHz/div) below
carrier
5-32
50MHz
lOMHz/div
)
carrier
1
.5-5
(9082 only)
8MHz
2MHz/div
)
i
At
least
20dB below
carrier
At
least
30dB below
carrier
(6)
On
the
UUT
set
the
OUTPUT
switch
to
X2
position
and
adjust the
VERNIER
control
for
a meter reading
of
+3dB.
(7)
On
the
spectrum analyser
set
30dB
input attenuation
and
the Log,
Ref,
vernier
to
-IdB.
(8)
Repeat operation
(5)
and
verify that
all
harmonics
are at least
24dB below
carrier for
frequencies
between
5
and
540MHz
and
at least
18dB
below
carrier for frequencies
between
1
.5
and
5MHz
(9082 only).
(9)
Disconnect
the
spectrum analyser.
9081
&
9082 Vol.
2.
5-16