User`s guide

6
Data entry methods
for user flatness correction
User flatness correction data is obtained by
connecting a power meter sensor at the desired
test port and calibrating the measurement system.
To make an accurate power meter measurement,
the power meter must be calibrated to the power
sensor by attaching the sensor to the "POWER REF"
output and performing a calibration. (It is assumed
that the user is already familiar with calibrating
and zeroing the power meter in use.) The accuracy
of the power meter measurement is also dependent
on the accuracy of the calibration factors used during
the measurement; the calibration factors must be
set for each individual correction frequency prior
to making the measurement. There are three methods
of user flatness correction data entry which are
primarily determined by the type of power meter
available.
A 437B power meter facilitates automatic entry of
correction data. Since the 8360 communicates with
the power meter over GPIB, it must be the system
controller during the data entry process. Only the
437B is capable of receiving frequency information
from the source, and incorporating the appropriate
power sensor calibration factor in the power meas-
urement (the user should be familiar with selecting
and editing the calibration factor tables). The 8360
then retrieves the power measurement data and
inputs the appropriate correction data in the array.
For power meters other than the 437B, the test port
power must be manually measured at each correction
frequency. At any given correction frequency, the
user must enter the appropriate power sensor cal
factor, measure the power, and then enter the cor-
rection data in the user flatness correction array
from the front panel of the 8360 (see Example 2).
Automatic test systems may be programmed to
interrogate the source for the test frequency, enter
the appropriate power sensor cal factor, make the
power meter measurement (with any power meter),
and send the data to the source so it can place the
appropriate correction data in the table. The 437B is
recommended since it is capable of internally storing
the cal factor information for different power sensors.
Other power meters will require a look-up table of
power sensor cal factors in the program.
Figure 7. Basic system configuration using an 437B Power Meter for automatic User
Flatness Correction data entry