HP 8340B Manual page 308

5-16.
LEVELED RF OUTPUT ADJUSTMENTS (Cont'd)
32. Using the DUT's front panel rotary knob (RPG), vary the ALC
level
from —20 dBm
to
+20
dBm.
Look for squegging as shown
in Figure 5*58. As the power level
is
increased, you
will need to
decrease the
vertical sensitivity (CHAN A) and
adjust
the
vertical positions on the oscilloscope.
If
any squegging occurs, examine the ENTRY
DISPLAY
to
determine the requested ALC
level.
If
the
ALC
level
is
at or below the maximum specified leveled power,
adjust
A24R5 (X2C)
counter¬
clockwise to eliminate the squegging. If the ALC
level
is
above maximum leveled power, what
you
are seeing
is
probably the RF output going unleveled and cannot be adjusted out.
NOTE
Squegging on the oscilloscope display
may
appear as shown in Figure
5-58 (power spikes
and oscillations) or
it
may appear as power spikes
without the oscillations. In either case the appropriate adjustment
should be made to eliminate the squegging.
Figure 5-58. Oscilloscope Display
with
Squegging Present
33. On the DUT, press [START FREQ] [1]
[3]
[.]
[5] [GHz]
[STOP FREQ]
[2] [0] [GHz] [SHIFT]
[PWR
SWP] [-] [2] [0]
[dBm]. Set the oscilloscope's
vertical sensitivity to 0.005
V/Div. Vary the ALC
level as in
step
32
and check for
squegging.
If any squegging occurs, examine the ENTRY
DIS¬
PLAY
to
determine the requested ALC
level.
If the ALC
level
is
at or below the maximum
specified
leveled power, adjust
A24R8
(X3C) counter-clockwise
to
eliminate the squegging.
If the ALC
level
is
above maximum leveled power, what you are seeing
is
probably the RF output going unleveled
and cannot be adjusted out.
If
the DUT
Is
an
HP
8341 B,
proceed to step 35.
34. On the
DUT, press
[START FREQ] [2] [0] [GHz] [STOP FREQ] [2] [6] [.] [5]
[GHz] [SHIFT] [PWR
SWP] [-] [2] [0] [dBm].
Set
the
oscilloscope's
vertical sensitivity to
0.005 V/Div.
Vary the ALC
level as
in step
32
and check for squegging.
If
any
squegging occurs, examine the
ENTRY
DIS¬
PLAY to determine
the requested ALC level. If
the
ALC
level is at or below the maximum specified
leveled power, adjust A24R11 (X4C) counter-clockwise to eliminate the squegging.
If
the
ALC
level
is
above maximum leveled power, what
you are
seeing
is
probably the RF output going unleveled
and cannot be adjusted out.
Adjustments
HP 8340B/41B