Spurious Check - Racal Instruments 9081 Maintenance Manual

SPURIOUS
CHECK
5.21
Test
Equipment
Required
Page 5-2
Table 5
Spectrum Analyser
Item
5
5.22
Procedure
(1)
Check
that
all
UUT modulation
control switches are at
OFF
and
set the
OUTPUT
switch
to
'X2'.
(2)
Tune the
UUT
to
25MHz
and
operate
the
VERNIER
to
give
a
3dB
reading
on
the
meter.
(3)
Connect
the
spectrum analyser
to
the
UUT 500
output
and
set the
analyser controls as follows
Input attenuator
Log.
ref.
Vernier
Bandwidth
Scanwidth
Video
filter
Scan time
20dB
+10
-
1
1
00kHz
lOMHz/div.
Off
5ms
(4)
Tune
the spectrum analyser from 0
-
1000MHz and check
that
any
spurious
frequencies are
below
the
following
levels, relative
to
carrier:-
Frequency Spectrum
Spurious Level
(Maximum)
0- 120MHz
-70dB
1
20-540MHz
-65dB
Above
540
MHz
-60dB
(5)
Repeat
(4)
but with the
UUT
tuned
to
the
following frequencies
(a)
50MHz
(b)
520MHz
Verify
that spurious frequencies are at
least
70dB below
carrier level
.
(6)
Tune the analyser
to
50MHz
and
slowly
tunethe
UUT
throughout range
1
.
Check
that
any spurious are
at least
70dB below
carrier in
the range
5MHz
to
35MHz
and
at least
55dB below
carrier in
the
range
1
.5MHz
to
5MHz
(9082 only).
9081
&
9082 Vol.2.
5-18