How does transmission lines cables filter the signal?

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I understand if you take i.e. 24 single wires and braid them, split both ends out as positive and negative to an antenna, should the cable filter such that the signal gets less powerful or even suppress the signal.

How does it filtrate, is 24 wires necessary?

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Anonymous 0 Comments

I’m not 100% sure I understand your question, or what you think happens in a cable.

Creating twisted pairs doesn’t directly remove noise. It helps ensure that any received interference is the same in both wires (it’s “common mode interference”), and that makes it easier to discard at the receiving end.

Long cables have a couple of important properties. One is resistance, which is proportional to the length. This does not reduce noise, it reduces signal strength. What you want is a high signal to noise ratio (SNR) to enable the receiver to interpret the data correctly. Resistance does not help because it reduces signal strength.

But long cables also have self-inductance. Inductance resists sudden changes in current flow, and can help reduce noise.

Putting lots of signals in close proximity creates cross-talk between them mostly due to their capacitance. That also increases noise and hurts SNR.

There’s nothing magical about the number 24.

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