Notes On Accuracy

The accuracy values in ‘Iable 6-7 were derived by combining the accuracy of the power meter and linearity of the analyzer’s internal source, as well as the mismatch uncertainty associated with the test set and the power sensor.

Power meter calibration measures the source power output (at the measurement port) at a single stimulus point, and compares it to the calibrated power you selected. If the two values are different, power meter calibration changes the source output power by the difference. This process is repeated at every stimulus point. The accuracy of the result depends on the amount of correction required. If the selected number of readings = 1, the final measurement accuracy is significantly affected by a large power change. However, if the selected number of readings is > 1, the power change on the second or third reading is much smaller: thus accuracy is much better.

Set source power approximately correct at the measurement port, then activate power meter calibration. This method can significantly increase the accuracy of the measurement when the selected number of readings = 1. Smaller accuracy improvements occur with a higher number of readings. Remember that mismatch errors affect accuracy as well.

Note

Power meter correction applies to one port only; the other port is not

 

corrected.

 

 

Application and Operation Concepts 6-107

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HP 8753E manual Corrected