Re: [IRCA] Broadband noise - (Getting rid of it)

["CHARLES HUTTON" <charlesh3@xxxxxxx>]

And a third (and the biggest) reason to me:

the energy we are trying to eliminate is random in amplitude due to the way 
that the data stream is scrambled. We can't remove it from the total energy 
without knowing what is supposed to be there on a symbol by symbol basis and 
that requires knowledge from the decoder which we don't have access to.

It's hopeless - as best I know - to try and build a noise reducer for 
broadband noise.



Chuck


>From: "Bob Foxworth" <rfoxwor1@xxxxxxxxxxxxxxx>
>Reply-To: Mailing list for the International Radio Club of 
>America<irca@xxxxxxxxxxxxxxxx>
>To: "Mailing list for the International Radio Club of 
>America"<irca@xxxxxxxxxxxxxxxx>
>Subject: [IRCA] Broadband noise -  (Getting rid of it)
>Date: Thu, 29 Sep 2005 14:03:00 -0400
>
>A filter device would be difficult to implement beacuse of two
>reasons, the signal is on for 100% of the time in the time
>domain (unlike electric fences, or rotating motor machinery
>where the signal is "on" for only a few percent of the time.)
>
>Secondly, the frequency domain is very wide so a notch
>filter would not be able to remove more than a small
>amount of the interference. I would think that phasing at the
>antenna level is the best approach. Once it is in the receiver
>chain, the constant-on, wideband aspect means it would
>cover virtually all of the desired signal, all of the time.
>
>A null at the antenna level is the best/only approach, I believe.
>
>Sorry to be so negative. Hope s/o else has an idea.
>
>- Bob
>


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