VDI VDI/VDE/DGQ/DKD 2622 BLATT 19 PDF

The series of standards VDI/VDE/DGQ/DKD 2622 lays down a technically well-balanced range of generally applicable calibration procedures for the calibration of instruments for measuring electrical quantities and thus creates a uniform, crosscompany basis for test equipment monitoring.

DIN EN 60966-1 describes not only the requirements applicable to the design and manufacture of assembled coaxial and radio frequency cables but also test methods. As regards the RF equipment used, the test procedures described here are not state of the art. It will not be dealing with the specific requirements of RF measuring cables nor with the subject of "Calibration".

This standard deals rather with the characterization of short RF measuring cables in particular, such as are often used in vector network analyzers (VNA) for the adaptation of test objects. The special requirements applicable to long RF measuring cables (> approximately 1 m) have not been investigated and are not taken into consideration. To what extent the methods described can also be applied to long RF measuring cables must be checked in the individual case.

Before correct measurement is possible with a VNA and the RF measuring cable connected to it, a calibration (in most cases called "Cal" or "Calibration" on the VNA) must be performed. Measurements are carried out with the aid of a calibration kit and many systematic effects of the VNA and the RF measuring cable (attenuation and reflection, in each case as magnitude and phase) are determined and for further measurements mostly compensated by a comprehensive software based mathematics capability in the VNA. In literature the term "systematic error correction" is used. For this reason the absolute attenuation and reflection of RF measuring cables play as measured variables a secondary role in the characterization of RF measuring cables. Much more important however is the stability of the attenuation and reflection properties of the RF measuring cables when there is movement, such as flexure or torsion. The instabilities of the RF measuring cables tend to enter into the measurement results randomly or in a way difficult to predict. As a rule, they can only be assigned to uncertainty of measurement as rough estimates.

RF measuring cables are not however limited to use with the VNA but are also used for other purposes. The procedures described in this standard may therefore, where applicable, be used there too. The weighting of the individual measured variables can be changed if necessary.