Other topics about Advanced Calibration
The simplified calibration calculates the calibration coefficients by skipping part of thru measurement (and line measurement for TRL measurement) that is necessary for the full 3/4-port calibration and the 3/4-port TRL calibration.
In the simplified full 3/4-port calibration, since the calibration coefficients are calculated while omitting part of the thru measurement data, the effect of errors when acquiring calibration data becomes larger than in the normal full 3/4-port calibration. Therefore, you must pay special attention to the following points when measuring data for the simplified full 3/4-port calibration.
The standard used for measurement must match its definition value.
Use a standard that provides good repeatability (stability).
Do not omit the length of the thru when defining the standard.
When using a user-created standard, verify the definition value.
For the N connector, note the discrimination between male and female.
Realize high reliability and repeatability for measurement.
Reduce the difference in external environment (such as temperature difference) between conditions of measuring calibration data and conditions of measuring actual data.
Set the power level of the stimulus signal to a value that does not generate compression.
Narrow the IF bandwidth.
Increase the averaging factor.
Use a cable whose change in amplitude/phase characteristics when bent is small.
Use high-precision connectors.
The types of thru measurement you can omit are determined by the ports you select. Some types of thru measurement cannot be omitted. The table below shows the types of thru measurement that can be omitted.
Omissible Thru Type at Full 3-port Calibration
|
Ports used |
Types of thru measurement that can be omitted |
|
Ports 1, 2, 3 |
2-3 |
|
Ports 1, 2, 4 |
2-4 |
|
Ports 1, 3, 4 |
1-4 |
|
Ports 2, 3, 4 |
2-4 |
For the simplified full 3-port calibration, (Optional) is displayed on the softkey of the type of thru measurement that can be omitted. For example, when the omissible thru measurement is 2-3, 2-3 (Optional) is displayed. The display after the execution of the omissible thru measurement is the same as that for a required thru measurement.
Omissible Thru Type at Full 4-port Calibration
|
Required thru measurements |
Types of thru measurement that can be omitted |
|
1-2, 1-3, 3-4 |
1-4, 2-3, 2-4 |
For the simplified full 4-port calibration, (Recommended) is displayed on the softkey of the type of thru measurement that can be omitted. For example, when the omissible thru measurement is 2-3, 2-3 (Recommended) is displayed. The display after the execution of the omissible thru measurement is the same as that for a required thru measurement, and the display for the remaining omissible thru measurement is 2-3 (Optional).
For the simplified full 4-port calibration, up to three thru measurements can be omitted, but it is recommended to perform two or more types of calibration because omitting all of them results in poor accuracy.
In the simplified 3/4-port TRL calibration, because the calibration coefficients are calculated while omitting part of the thru/line measurement data and line/match measurement data, the effect of errors when acquiring calibration data becomes larger than in the normal 3/4-port TRL calibration. Therefore, you must give more attention to data measurement for the simplified full 3/4-port calibration than for the ordinary 3/4-port TRL calibration.
The types of thru/line measurement and line/match measurement you can omit are determined by the ports you select. Some types of measurement cannot be omitted. You cannot omit thru/line measurement only or line/match measurement only, even for an omissible measurement path.
Omissible Thru type at 3-port TRL calibration
|
Ports used |
Omissible measurement |
|
Ports 1, 2, 3 |
2-3 |
|
Ports 1, 2, 4 |
2-4 |
|
Ports 1, 3, 4 |
1-4 |
|
Ports 2, 3, 4 |
2-4 |
For the simplified 3-port TRL calibration, (Optional) is displayed on the softkey of the omissible thru/line measurement. For example, when the omissible thru/line measurement is 2-3, 2-3 (Optional) is displayed. The display after the execution of the omissible thru/line measurement is 2-3 Thru/Line.
For the softkey of an omissible line/match measurement, (Optional) is displayed as in the case of the omissible thru/line measurement. For example, when the omissible line/match measurement is 2-3, 2-3 (Optional) is displayed. The display after the execution of the omissible line/match measurement is 2-3 Line/Match.
The softkeys (Fwd and Rvs) for forward measurement and reverse measurement for the omissible line/match measurement do not change.
|
Required measurements |
Omissible measurements |
|
1-2, 1-3, 3-4 |
1-4, 2-3, 2-4 |
For the simplified 4-port TRL calibration, (Recommended) is displayed on the softkey of the omissible thru/line measurement. For example, when the omissible thru/line measurement is 2-3, 2-3 (Recommended) is displayed. The display after the execution of the omissible thru/line measurement is 2-3 Thru/Line, and the display for the remaining omissible thru/line measurement is 2-3 (Optional).
For the softkey of an omissible line/match measurement, (Recommended) is displayed as in the case of the omissible thru/line measurement. For example, when the omissible line/match measurement is 2-3, 2-3 (Recommended) is displayed. The display after the execution of the omissible line/match measurement is 2-3 Line/Match, and the display for the remaining omissible line/match measurement is 2-3 (Optional).
The softkeys (Fwd and Rvs) for forward measurement and reverse measurement for the omissible line/match measurement do not change.
For the simplified 4-port TRL calibration, up to three thru/line measurements and line/match measurements can be omitted, but omitting all of them results in poor accuracy.