How to remove the noise which has the same frequency as that of the system.

[teslagrc]

Hello everyone,
If my system contains noise in the same frequency range as that of the useful signal,how can I remove the noise without affecting the required signal?
Thank you.

 

[Genovator]

Generally noise are filtered by low pass filters, because noises are most of the time of high frequencies. Since the noise is of signal frequency, any attempt of filtering it will damage the signal also. So you have to make sure the source is noise free.
But if the noise is of low amplitude, then maybe you could filter it. Its could be done in square wave signals by over-biasing it with a transistor.

 

[permute]

You either need more sources (with diversity) or some knowledge of either the noise, the signal, or both.

 

[Genovator]

Adding to what @permute said, usb protocols consist two data lines- D+ & D-. D+ is the positive signal while D- is its negative image. The profit by using two similar data lines is that even if any one data line is affected by noise, or both, the comparator receiving both these lines will easily identify and remove the noise.