HP 8568B, Руководство по испытаниям и регулировке работы, Страница: 240 / 313

19. Second Converter Adjustments
Second Converter
27. Key in
[
FREQUENCY SPAN
]
0 Hz.
Filter
Adjustments
28. On the synthesized sweeper, key in 240 MHz, 50 MHz,
and 10
29. Connect the synthesized sweeper’s SWEEP OUTPUT (rear panel),
Z-AXIS BLANK/MKRS (rear panel), and PULSE MODULATION
INPUT (front panel) to the proper rear-panel connectors on the
scalar network analyzer as shown in Figure 3-73.
30. On the scalar network analyzer, press PRESET, turn channel 2 off,
and press (A/R).
31. Connect the synthesized sweeper’s output to the power splitter as
shown in Figure 3-72.
32. Connect one arm of power splitter to scalar network analyzer R
input. Connect other arm of power splitter to A input, using a
BNC to SMB snap-on test cable and necessary adapters.
33. Set the scalar network analyzer to 1 and set (REF
LEVEL) to -16.00 Set REF POSN (press REF POSN) to the
fourth division from the bottom using the data knob.
34. On the synthesized sweeper, press (ON),
SWEEP
),
and
Set to 500 ms.
35. Adjust REF LEVEL for a mid-screen response of the
signal on the scalar network analyzer.
36. Connect the test cable from the power splitter output arm to
Pilot First IF IN.
37. Connect cable 80 (gray/black) from (PILOT IF) to
the scalar network analyzer’s A input. Set to 10
38. On the spectrum analyzer, key in [SHIFT]
Note
Hold (SHIFT] in until the LED lights, then press until the
sweep is free running.
39. On the synthesized sweeper, set for a frequency of 2017.6
MHz and to 50 MHz.
40. Adjust on the synthesized sweeper to center the
signal.
41. Adjust and for best shape and
flatness at maximum amplitude of signal displayed on Scalar
network analyzer. A typical properly-adjusted
filter
response is shown in Figure 3-74. See Figure 3-73 for location
of adjustments. The
filter response at the 3 points
should be MHz. See Figure 3-74 and Figure 3-75 for a typical
PILOT IF response for a SHIFT LO and a SHIFT
LO
3-126 Adjustments