I'm looking for a way to shield or protect produced signal or wave. In mechanics suppose you run the wave in tunnel. Is there a way to do it in transmitting the signals or waves created by mobile phone or wifi or in the internet?
Signal integrity is a full area of electrical engineering and signal engineering. A few examples :
- To protect a propagating signal in free-space you can emit it louder (=more transmitting power, hence increasing signal to noise ratio (SNR)).
- Numerical transmissions often include error correcting codes.
- To protect propagating signals in cables, most of them are electromagnetically shielded.
I may detail my answer according to what you want to know exactly.
If you send a signal wirelessly, your options would be: 1) avoiding that a bad guy gets the signal in the first place (antenna, beamforming, frequency hopping) 2) avoiding that a bad guy can make any sense of the signal (eg encryption)
Some schemes might blur the distinction between 1 and 2.
I have a hard time coming up with any other scheme.
Is this an academic exercise, or a practical problem?