HP 8340B Manual page 44

4-7.
SPURIOUS SIGNALS TEST (10
MHz to
22
GHz
-
HP 8340B only)
(10
MHz to
20
GHz
•
HP 8341 B)
NOTE
When using
a
spectrum analyzer other than the HP 8566A/B, the
spec¬
trum analyzer
may generate some mixing products that could appear
on
the display.
If
a
signal
is in question, increase the
spectrum analyzer
input attenuation by
10 dB,
note
if
signal decreases in
amplitude by
10
dB, then return the attenuator to its original position.
If
the signal
in
question comes from an external source,
it
will
change
by
exactly
10 dB.
If
the signal in
question originates
in the spectrum analyzer, the
level will
either change by
greater or
less than 10 dB or
may not change at
all.
The
DUT's rotary knob circuit may generate some noise spikes when the
knob is
rotated.
These
signals should disappear when rotation is
stopped.
If
a
spurious signal is found and
it
appears
out of specification, check
the fundamental signal amplitude to
ensure
it is at
0
dBm. Then check
spurious level by substituting
a
known amplitude signal
on
the spectrum
analyzer.
6.
Tune
the spectrum analyzer across its full frequency range. Look for any spurious signals. For
each spurious response determine what mechanism generated
the spurious response and what
specification applies.
a.
Is the spurious response
in
question an integer multiple of the HP
8340B/41B RF output
signal?
If
it is,
the "harmonic" specification applies.
b.
Press the
DUT's [SHIFT]
key and then
[M2]
to display, from left to
right,
the YO harmonic
number and the YO frequency.
Is the spurious response in
question an integer multiple of the
YO frequency (and not
a
harmonic of the RF signal)? If it is
the
"subharmonic and multiples
thereof" specification applies.
NOTE
Press the [CW] key
to
view the CW frequency
in
the ENTRY DISPLAY.
c.
If
the spurious
response
in
question does not
meet one of the above criteria, the
"non-
harmonically related" specification applies.
7.
Repeat steps
4
through
7
at any frequency of interest within this
frequency
band.
8.
Press the
DUT's [STOP FREQ]
key and enter the stop frequency for the next frequency band.
Press the
[START FREQ]
key and enter the start frequency for the next frequency band.
Repeat
steps
3 through 8 until
all DUT
frequency bands have been tested up to
22 GHz
(for
HP 8340B), or
20 GHz
(for HP 8341
B).
HP 8340B/41B
Performance Tests
4-39/4-40