HP 8340B Manual page 226

5-3.
100
MHz VOLTAGE-CONTROLLED CRYSTAL OSCILLATOR (VCXO),
A30 (Cont'd)
6.
Disconnect cable W35 from A30J2100 MHz OUT.
Connect Spectrum Analyzer RF Input to A30J2.
7. Adjust
A30C4100 MHz ADJ through
its full
range while
monitoring frequency
indication on Spec¬
trum Analyzer. Adjustment should provide
a
minimum adjustment range of
plus and minus
300
Hz
centered about 100 MHz. If
adjustment does
not provide sufficient range, select
new values for
factory selected components
A30C8
and
A30L4. A30L4
is
used to
center the adjustment about
100
MHz and A30C8
is
used to adjust the range of A30C4. Refer to Table
5-2
for range of values.
Refer to Table 5-4
for HP
Part Numbers.
8. Adjust A30C4 100
MHz
ADJ for Spectrum Analyzer indication of
100.0000 MHz ±0.0001 MHz.
9.
Disconnect cable A30W1 at A31J1 400 MHz
IN and connect the open end of this cable (A30W1) to
the Spectrum Analyzer
input using
a
BNC to SMB Snap-on
test cable and
SMB
male-to-male
adapter. Set Spectrum Analyzer controls to view
a
400 MHz
signal.
10.
The 400 MHz
output should be
-10 dBm ±3
dB.
11. Adjust the DC power supply for 0V at A30TP1 (TUNE). Connect Spectrum Analyzer
to
A30J2.
Adjust Spectrum Analyzer
to
view 100
MHz.
12.
Frequency
indication on Spectrum Analyzer
should be less than 100
MHz.
If
not,
repeat Steps
2
through
7.
13.
Set power
supply
for
an output of
-25
Vdc. Verify TUNE test point A30TP1
is
at
-25
Vdc.
14.
Frequency indication on Spectrum Analyzer should be greater than
100
MHz.
If
not,
repeat Steps
2
through
7 and verify
that the oscillator's range is
100
MHz
±300
Hz. Disconnect
power
supply
from A30TP1.
Reconnect
10
MHz
signal cable from Spectrum Analyzer to the
DUT's rear-panel
EXT FREQUENCY STANDARD.
400 MHz OUTPUT ADJUSTMENT
15.
Set Spectrum Analyzer
to
500 MHz center frequency and 100
MHz
frequency span per division.
16.
Connect Spectrum Analyzer
to A30W1 cable.
Adjust A30C3, A30C2,
and A30C1 400
MHz
adjust¬
ments,
in that order, to maximize the
400 MHz
signal's output
power and minimize
all
harmonics
of 100
MHz. The 400 MHz signal
should be —10
dBm ±3dB
and the harmonics at 100, 300, 500,
600.700,
and 900
MHz
must be
greater
than
40
dB down from the 400
MHz
signal.
Harmonics at
200
MHz
must be greater than 25
dB down from
the
400 MHz
signal. Harmonics
at
800
MHz
must
be greater than 15
dB down from
the
400 MHz
signal.
It
may
be necessary to perform the
adjust¬
ments more
than once. This should be done
in the order stated each time through the adjust¬
ments.
17.
The
amplitude of
the 400
MHz
signal should be —10
dBm ±3
dB.
This amplitude
is
set by
selecting attenuator network resistors A30R67, A30R68, and A30R69.
18. If
the amplitude of the
400 MHz
signal
is not within
3 dB of
-10
dBm,
note the amplitude and
change the
values of A30R67, A30R68,
and
A30R69
as necessary to adjust the amplitude to -10
dBm ±3
dB. Table
5-5 contains
a
list
of attenuations
in 1
dB steps and the
corresponding values
for the
attenuator network resistors to adjust the
level to —10 dBm. Refer to Figure
5-6
for
location of resistors.
HP 8340B/41B
Adjustments 5-21