4
ALC
5
rmware. In coupled op eration, when desired power output is set via
4
POWER LEVEL
5
, the ALC level and attenuator are set automatically to
provide the most accuracy for the p ower requested.
Uncoupled Op eration.
In some applications it is advantageous to
control the ALC level and attenuator separately, using combinations
of settings that are not available in coupled op eration. In uncoupled
mo de (
NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN
Uncoupl Atten
), when the desired p ower output is set via
4
POWER LEVEL
5
, only the ALC level is changed. The attenuator setting
is changed via
NNNNNNNNNNNNNNNNNNNNNNNNNNNNN
Set Atten
.
One use of uncoupled op eration is p ower sweep, where the
output p ower linearly tracks the sweep voltage ramp. The swept
signal generator can generate p ower sweeps of up to 40 dB,
depending on frequency. The p ower at the start of the sweep is
set via
4
POWER LEVEL
5
(coupled op eration) or by a combination of
4
POWER LEVEL
5
and
NNNNNNNNNNNNNNNNNNNNNNNNNNNNN
Set Atten
(uncoupled op eration). The sweep
range is entered by selecting
NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN
Power Sweep
. If the sweep range
entered exceeds the ALC range (stop power greater than maximum
available p ower), the
UNLVLED
warning message app ears at the end of
sweep. No warning is given at the time of entry. If the start power is
entered when the swept signal generator is in coupled op eration, the
ALC level is set no lower than
0
10 dBm, limiting the available p ower
sweep range. Using uncoupled operation and setting the ALC lev
el to
0
20 dBm gives an additional 10 dB of sweep range.
External Leveling -
NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN
Leveling Mode Normal
,
NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN
Leveling Point ExtDet
or
NNNNNNNNNNNNNNNNNNNN
PwrMtr
or
NNNNNNNNNNNNNNNNNNNN
Module
In externally leveled op erations, the output power from the swept
signal generator is detected by an external sensor. The output of this
detector is returned to the leveling circuits, and the output p ower is
automatically adjusted to keep the p ower constant at the p ointof
detection. Figure A-2 shows a basic external leveling arrangement.
The output of the detected arm of the splitter or coupler is held
constant. If the splitter response is at, the output of the other
arm is also constant. This arrangement oers sup erior atness over
internal leveling, esp ecially if long cables are involved. Flatness
may be improved with user atness correction (
4
FLTNESS ON/OFF
5
,
NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN
Fltness Menu
) applied at the external leveling point.
Operating and Programming Reference A-7
To Next Page
Loading...
Need help?
General
