5-8.
YO LOOP ADJUSTMENTS (Cont’d)
60
70 MHz
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 51
to position 1 and set S2 to the J2 position. The YO Loop should
now be locked as indicated by A50051 (green
LED)
being lit.
24. On the OUT, press [INSTRPRESET] [CW] [3]
[GHz].
25. Set up the Spectrum Analyzer as follows:
INSTR PRESET
Press
TRACKING GENERATOR AMPLITUDE
Fully Clockwise (0 dBm)
INPUT IMPEDANCE
1 Megohm
AUTO RANGE
OFF
REF. LVL. TRK
OFF
START FREQ
0Hz
STOP FREQ
100 kHz
dB/div
1 dB/div.
REF. LEVEL
—25 dBm
RANGE (use STEP keys)
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 [STOREA
—~
B] to store the trace from A into Trace B. On the
Special Test Fixture, set switch 51 to position
2. The Spectrum Analyzer should display the two
traces similar to Figure 5-25, Waveform B.
5
20
30
Figure 5-22.
IF Frequency Response Limits
5-48
Adjustments
HP 8340B/41B