[Elecraft] MCU 4.42 Beta Firmware

[B Hunt]

Here's another discussion by Lyle, KK7P, of Noise Reduction and what you 
are getting with various settings.  Link to the thread here: 
http://elecraft.365791.n2.nabble.com/Noise-Reduction-parameters-td457358.html#a457359

Brian
K0DTJ

On 9/21/2011 2:38 AM, David Windisch wrote:
> Hi, Adrian:
>
> I have found:   http://www.elecraft.com/K3/K3FAQ.htm  to be helpful.
>
> Here is a quote regarding NR:
>
> QUOTE
>
> How does the Noise Reduction work?
>
> NR depends on correlation of the present input with previous input. The
> system does not actually provide Noise Reduction; it provides Signal
> Selection. In other words, its default is to pass nothing at all. It has to
> believe there is a signal present, and then it builds a filter, or set of
> filters, around the spectral components of the signal it thinks is there.
>   Random noise has no correlation, voice has moderate but not perfect (unless
> you whistle a pure tone) and CW has excellent correlation.  As a result,
> noise is heavily suppressed (no filter is built to pass it), voice is
> partially suppressed (hence it needs some additional gain to compensate for
> this effect so the same AF level will produce about the same audio level
> with a moderate S/N speech signal) and CW is hardly suppressed at all (hence
> it does not need any gain boost).
>   NR is not recommended in Data Mode.  Data is already getting a matched
> filter in the demodulator. You might lose a few symbols as the NR settles
> around the signal, and it might suppress a very weak signal that you could
> otherwise copy.
>   NR in the end is intended for modes you listen to.
>
> UNQUOTE
>
> Hth.
>
> Brgds,
> Dave, N3HE
>
>
> --
> View this message in context: http://elecraft.365791.n2.nabble.com/MCU-4-42-Beta-Firmware-tp6813673p6815465.html
> Sent from the Elecraft mailing list archive at Nabble.com.
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