amplifier and filter solutions for sharp impluse signal

Why do you post the same message again ?

It would help a lot if you could specify more details on the physics of the comm channel.

This is indeed the trickiest part : if the noise distribution is not stable, ( i.e : variable noise level vs frequency band ) then the SNR will be variable - and so the error rate.

There is a way to improve such situation, called "spread spectrum" which enlarges the signal spectrum over the channel bandwidth, this gives a large redundancy to overcome severe interference, and greatly helps to lower the error probability.

Another technique is used for channels having time-variant impulse responses, which is a consequence of the constantly changing physical characteristics of the channel.

Does it sounds like the problem you are facing ?

Yes, whatever will be the choice, you still keep the option to improve the overall transfer by implementing a convenient error detection/correction code at the software level.

However I doubt that NRZ is a good choice in this tricky case, you may have to use a convenient modulation w/ matched filters.

Anyway such subjects are well covered - in depth - in books that I strongly suggest you to read :

HTH