A shielding unit is inserted through the box s opening.
Cable shielding effectiveness measurement.
Making accurate measurements is a challenge because shields have many different shapes and purposes.
Cable interconnects which allow cables inside the cage to connect to cables outside may undergo modification for additional connectors that damage the shielding integrity.
The measurement method is validated by comparing measurements on an isolated conductor penetrating the shield with a simple theory based on basic circuit theory in combination with antenna theory.
Ventilation is another example and one that is usually problematic with regards to shielding effectiveness.
There could also be changes in compliance standards.
This is a typical margin recommended by various industry specifications.
The shielding effectiveness is measured by comparing the reading of reference and the load devices.
To verify the periodic calibration two gold standards are employed.
An efficient and repeatable measurement method for determining shielding effectiveness of cable feedthroughs based on the use of nested reverberation chambers is presented.
This method is effective for frequencies less than 500 megahertz.
When a cable specification calls for 90 db of rf shielding the 100 db dynamic range allows a 10 db margin in the measurement range.
Our most common request is to measure se for connectors and cables.
Measurements were made in the frequency range 0 5 to 100 mhz.
For these products we primarily use two techniques the triaxial fixture method and the mode stirred method.
It involves the use of a sealed box with an opening.
Measurement method for determining shielding effectiveness of cable feedthroughs.
The method is offered as a standard technique for measuring the shielding effectiveness of shielded cables.