Anritsu 682XXB - Manual (Page 128)

Log Amplifier
Zero Calibra-
tion Before the Switched Filter Shaper Amplifier can be
adjusted, zero calibration of the ALC Log amplifier
must be performed to eliminate any DC offsets.
1. Perform ALC Log amplifier zero calibration as
follows:
a. At the
$
prompt on the PC display, type:
calterm 115
and press <ENTER>.
The
$
prompt will appear on the screen when
ALC Log amplifier zero calibration is complete.
(This can take up to 3 minutes for a 40 GHz
unit.)
b. Record step completion on the Test Record.
NOTE
The following Limiter DAC adjustment
procedure applies only to 682XXB/
683XXBs with Option 15B (High Power
Output). If your instrument does not have
this option, go directly to the Shaper DAC
adjustment procedure.
Limiter DAC
Adjustment The following steps in the procedure let you adjust
the Switched Filter Limiter DAC which controls the
maximum gain of the Switched Filter Shaper Ampli-
fier. Each frequency band will be scanned for the
maximum unleveled power point before adjustment
of the Limiter DAC to ensure that the Shaper Am-
plifier is not driven to saturation.
1. Set up the 562 Network Analyzer as follows:
a. Press the System Menu key.
b. From the System Menu display, select RESET.
c. Press CHANNEL 2 DISPLAY: OFF.
d. Press CHANNEL 1 DISPLAY: ON.
e. Press CHANNEL 1 MENU key.
f. From the Channel 1 Menu display, select
POWER.
g. Press OFFSET/RESOLUTION.
h. Set Resolution to 5 dB/Div.
i. Adjust Offset to center the display.
4-18 682XXB/683XXB MM
SWITCHED FILTER
CALIBRATION SHAPER CALIBRATION