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interference

Signals that occur unintentionally as stray signals due to capacitive, inductive or galvanic coupling on the lines are called interference signals. Interference signals are generated on the one hand by crosstalk between adjacent lines, and on the other hand by external EMC influences. Interfering signals impair the received signal behavior, which is why one tries to prevent or reduce these signals

and, above all, their radiation, by means of targeted cable design. With shielded cables

, however, the external influence is so small that it can be neglected. In unshielded cables, however, adjacent signal lines can have an additional negative effect on theattenuation crosstalk ratio

(ACR).In unbalanced cables, such as coaxial

cables, one or more shields dissipate the interference via the shielding. In the case of balanced, unshielded UTP cables, the interfering signals are compensated by a completely balanced cable structure. The structure of the cores is selected in such a way that interference signals interspersed by the cable stranding occur on both cables with the same strength and the receiver

only receives the difference of the interference signals. Interference

on balanced cables

on balanced cables

The interference signal originates on the one hand from the crosstalk of adjacent lines and on the other hand from external EMC influences. With shielded cables, however, the external influence is so small that it can be neglected. With unshielded cables, however, adjacent signal lines can have an additional negative influence on the ACR ratio.

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Englisch: interference
Updated at: 03.08.2004
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