Received-SPF: neutral (google.com: 193.82.116.20 is neither permitted nor denied by best guess record for domain of owner-rsgb_lf_group@blacksheep.org)
DomainKey-Status: bad (test mode)
DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws;
  s=s1024; d=btinternet.com;
  h=Received:Message-ID:From:To:References:Subject:Date:MIME-Version:Content-Type:Content-Transfer-Encoding:X-Priority:X-MSMail-Priority:X-Mailer:X-MimeOLE;
  b=31ScaxGH3Z/AqGm8FZ7TqO69Zg43Ft7we9TCkXO1Wiczw5FdPaporlfMZC61hJHICSpteqYU1bDoef7yRtHuUUh9YpTxGhfv90fKobWKsT9ZZ3afuiepJdBwS1+2VJy15iCCC3YVEu+f/CXqJcBkGTE+U18QjRTzqENQi4qm4RA=  ;
Message-ID: <005e01c7027b$9b23dc00$0300a8c0@lark>
From: "Alan Melia" <alan.melia@btinternet.com>
To: <rsgb_lf_group@blacksheep.org>
References: <6.1.1.1.2.20061107151228.07979730@mail.casema.nl>
Date: Tue, 7 Nov 2006 14:47:07 -0000
MIME-Version: 1.0
Subject: LF: Re: DSP-filter for aural CW
Content-Type: text/plain;
	charset="iso-8859-1"
Content-Transfer-Encoding: 7bit
Sender: owner-rsgb_lf_group@blacksheep.org
Precedence: bulk
Reply-To: rsgb_lf_group@blacksheep.org
Status: O

Hi Dick, to some extent this will depend upon the type of sound-card you
have. I use Alberto's Spectran but Wolf's Spectrum lab will do it. The card
problem we found is that some cards will not operate in duplex
(simulataneous input and output) I have some Creative Labs PCI64 that suffer
from this problem. The PCI128 is OK. I would imagine the later cards are
probably ok. You might find the improvement is not a great as you might
hope......but I am not a "real" CW op !!

Cheers de Alan G3NYK

----- Original Message -----
From: Dick Rollema <dickrollema@casema.nl>
To: LF-Group <rsgb_lf_group@blacksheep.org>
Sent: 07 November 2006 14:25
Subject: LF: DSP-filter for aural CW


> To All from PA0SE
>
> Does someone know whether a DSP filter using the sound card of the
computer
> can be found on the internet , that can filter the audio output of the
> receiver with an adjustable bandwidth down to, say, 20Hz or so?
>
> I use a passive audiofilter between the receiver and the headphones with
> four tuned circuits. It has a bandwidth of about 25Hz, a centre frequency
> of 900Hz and a linear phase characteristic to avoid ringing.  But perhaps
a
> DSP filter could do even better.
>
> 73, Dick, PA0SE
> JO22GD
>
>
>