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

[Barry McLarnon <bdm@xxxxxxxxxx>]

On Thursday 29 September 2005 14:12, CHARLES HUTTON wrote:
> 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.

This discussion isn't about that 4-letter word starting with "I", it's 
about noise... yeah, that's the ticket. :-)

I agree with Bob and Chuck... the digital signal is practically 
indistinguishable from broadband noise.  It has a flat spectrum,
and no temporal characteristics (such as a pulse-type waveform) that
could be used for a noise blanker kind of approach.  The best bet is 
antenna nulling, but if lots of stations have digital sidebands, there's 
way too much to null...it's like your noise floor went way up, and it's 
game over.

Barry

-- 
Barry McLarnon VE3JF  Ottawa, ON

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