On Sun, Jan 5, 2020 at 11:28 AM, Jeff Anderson wrote:
. (And B. P. Hand recognizes this in the Feb 1970 issue of the HP Journal when
he states that imperfect characterizations of the standards are one of the
sources of error.)
A slight clarification -- Hand was referring to errors that were *not* corrected with the error correction process. Noise is one of those errors. Imperfect characterizations of the standards are another. []
Here are some other quotes regarding the importance of the accurate characterization of standards...
From HP's 8753D User's Guide [], Page 6-50: "When you use a measurement calibration, the dynamic range and accuracy of the measurement are limited only by system noise and stability, connector repeatability, and the accuracy to which the characteristics of the calibration standards are known."
Note that last clause: "the accuracy to which the characteristics of the calibration standards are known." In other words, the more accurately known the characteristics of the standards used for the calibration process are, the more accurate will be the measurements.
From Keysight, "Specifying Calibration Standards and Kits for Keysight Vector Network Analyzers []: "The accuracy of subsequent device measurements depends on the accuracy and stability of the test equipment, the accuracy of the calibration standard model, and the calibration method used in conjunction with the error correction model."
Note that "the accuracy of the calibration standard model" is one of the factors determining the accuracy of measurements.
From Mini-circuits App Note AN49-017 []: "Approximating SOL standards by their canonical/ideal reflection coefficients will undoubtedly incur significant inaccuracies in phase measurements as the phase cannot be treated as static due to the ¡®line¡¯ in the transmission line model"
In other words, do NOT use (-1,1,0) as your SOL characterizations. Instead, use the standards' actual characterizations.
- Jeff, k6jca
