HP 8340B Manual page 250

5-8.
YO LOOP ADJUSTMENTS (Cont'd)
Figure 5-22.
IF
Frequency Response Limits
GAIN AND PHASE MARGIN ADJUSTMENT
20. Fabricate the special test fixture as shown in
Figure
5-23.
21. Place the
YO Loop
in
the Service
Position and remove the cover
from
the
A49
Phase Detector
board. Remove
jumper A49W1 from
the Phase Detector board.
22.
Connect the Special Test
Fixture and the
Spectrum Analyzer
to
the YO Loop as shown
in Figure
5-24.
23. On the Special
Test
Fixture, set
S1
to position
1
and set
S2 to the J2 position. The YO Loop
should
now
be locked as indicated by A50DS1 (green LED) being
lit.
24. On the DUT, press
[INSTR PRESET] [CW] [3] [GHz].
25.
Set
up
the Spectrum Analyzer as follows:
INSTR PRESET
..................
TRACKING GENERATOR AMPLITUDE
INPUT IMPEDANCE
...............
AUTO RANGE
....................
REF. LVL.
TRK
...................
START FREQ
....................
STOP FREQ
.....................
dB/div
..........................
REF. LEVEL
.....................
RANGE
(use
STEP keys)
...........
...............
Press
Fully Clockwise
(0 dBm)
...........
1
Megohm
................
OFF
................
OFF
................
0
Hz
.............
100
kHz
.............
1
dB/div.
............
-25 dBm
............
-15
dBm
26.
A
trace similar to
Figure
5-25, Waveform
A should be displayed on the Spectrum Analyzer.
27. On the Spectrum Analyzer, press
[STORE A
—
B] to
store the trace from
A
into
Trace
B.
On the
Special Test Fixture, set switch
S1
to position 2.
The Spectrum Analyzer should display
the two
traces similar to Figure 5-25, Waveform
B.
Adjustments
HP 8340B/41B