I
-
I
-
Externally leveling the Sweeper
leveling with detectors/couplers/splitters
External
 
leveling
 
with
 
the
 
option
 
1El
 
step
 
attenuator
Some external leveling applications require low output power from the
sweeper. The sweeper automatically uncouples the attenuator from the ALC
system for 
all
 external leveling points. Note that in external leveling modes,
the UNCPLD annunciator is lit.
For example, leveling the output of a 30 
dB
 gain amplifier to a level of
-
 10 
dBm
 requires the output of the sweeper to be around -40 
dBm
 when
leveled. At some frequencies this level is beyond the range of the ALC
modulator alone. If so, the UNLEV warning message is displayed. Inserting 40
dB
 of attenuation results in an ALC level (power level + attenuator value) of
0 
dBm,
 which is well within the range of the ALC. This gives a margin for
AM or other functions that vary the power level.
The ALC level should be greater than or equal to -10 
dBm
 for “A” model
sweepers (standard power), and -5 
dBm
 for “B” model sweepers (high
power). Adjust the attenuator so that the ALC level is within the specified
power range of your sweeper. For an “A” model sweeper, this is achieved by
using attenuation equal to the tens digit of output power. Example: for a
desired sweeper output power of -43 
dBm;
 do the following:
1.
 Press 
CSHIFT)
 SPECIAL 
(YJ
2. Set the attenuator to 40 
dB:
 press 
c40)
 
[GHz/dB(mL)
See
 
also
To obtain flatness corrected power refer to the chapter entitled “Creating User
Flatness Correction Arrays, 
n
 later in this manual.
2-6