User`s guide

12
Example 4:
Scalar analysis measurement
with user flatness corrections
The following example demonstrates how to
setup a scalar analysis measurement (using an
Agilent 8757 scalar network analyzer) of a 2 to
20 GHz test device such as an amplifier. User
flatness correction is used to compensate for
power variations at the test port of a directional
bridge. Follow the instructions to set up the source,
then configure the system as shown in Figure 10.
Since this example uses a 437B power meter to
automatically enter correction data into the array,
it is necessary to turn off the 8757 system interface
so that the source can temporarily control the power
meter over GPIB. When the correction data entry
process has been completed, enable user flatness
correction and set the desired test port power
level. Then store the correction table and source
configuration in the same register that contains
the analyzer configuration. Reactivate the 8757 sys-
tem interface and recall the stored register. Make
sure that user flatness correction is still enabled
before making the measurement.
When a 437B power meter is used to automatically
enter the correction data, the correction calibra-
tion routine will automatically turn off any active
modulation and then reactivate the modulation
upon the completion of the data entry process.
Therefore, the scalar pulse modulation that is auto-
matically enabled in a scalar measurement system
will be disabled during a 437B correction calibration.
The user flatness correction array cannot be stored
to a disk. You must make sure that the array is stored
in one of the eight internal registers. Recalling a
file from a 8757 disk will not erase the current
array; therefore a user may recall an array from an
internal register, then recall an associated file from
a disk.
Note: The 8360’s rear panel language and address
switches must be set to 7 and 31 (all 1s), to allow
the user to change the language or address of the
source via the front panel. The default settings are
TMSL and 19, respectively.
Command Description
[PRESET] source Reset to a known state
Set the source to
Analyzer mode
SYSTEM [MENU] Access system softkey menu
[GPIB Menu] Access GPlB softkey menu
Programming Language Select analyzer language as the
[Analyzer] instrument's external interface language
Asterisk = active function
Figure 10. Scalar system configuration
83620B
synthesized sweeper
Sweep output
Z-axis blank/mkrs
Stop sweep in/out
GPIB
GPIB
RF output
Sweep in
Pos Z blank
Stop sweep
8757 system interface
85025E detector
11667B
power splitter
85027B
directional bridge
Test port
8757C
scalar analyzer
85025E detector
DUT
8485A
power sensor
437B
power meter