RadiMation Application Note 141

How to create and apply a cable correction

This RadiMation^® application note explains how to create a cable correction and how to select it in RadiMation^®. Cable corrections can be used for several reasons:

• for cables in emission measurements
• when using attenuators in a conducted immunity calibration setup
• correcting a cable from a coupler to a powermeter in an immunity test.

By specifying the actual correction for the cable loss, RadiMation^® will be showing the correct measurement values.

The procedure to determine and select a cable correction, consist of 3 steps:

1. Create a calibration file.
2. Create a Cable device driver and apply the correction file.
3. Add the cable to the test equipment.

Create a calibration file

There are two methods to create a correction file:

Measure attenuation or gain

It is possible to use the attenuation gain measurement to automatically create a correction and measure the cable or attenuator with a signal generator and a power meter or spectrum analyser.
this is described here: Attenuation / Gain System Calibration

Create a correction manually

To create a correction file manually, first create a new correction file, using the menu:

    File

       New

          Correction

The Insert row button can be used to add additional rows. The cells in the frequency and correction columns can be used to specify the correct frequencies and the corresponding attenuation values.

The correction file can be saved to disk, by selecting from the menu:

    File

       Save correction as...

It is also possible to paste data from for example Microsoft Excel with the Paste button . Make sure the data on the clipboard is specified in present in MHz and attenuation values expressed in dB. This feature is particularly used when correction values are supplied in a digital calibration certificate or is measured with other software.

Create a cable device driver

A new cable device driver can be created by selecting from the menu:

    Devices

       Devices

          Cables

             Add...

1. Choose Configurable cable and click New.
2. Enter an appropiate description for the cable or attenuator.
3. The Device driver settings window, is shown. The fields in this window can be specified to provide any additional information regarding the cable.
4. In the Correction files section, the previously saved correction file can be selected at Cable Loss.
5. Click OK to close the window.

Add the cable to the test equipment

To apply the cable, open test equipment:

    Test-sites

       Configure

1. At the pull down menu select the applicable test equipment, or if needed create a new one.
2. Select the 5th tab called "Cables"
3. Click the button "Add" and add the cable to the applicable path.