Return-Path: Received: (qmail 27189 invoked from network); 15 Oct 2002 06:34:21 -0000 Content-Transfer-Encoding: 8bit Received: from warrior.services.quay.plus.net (212.159.14.227) by mailstore with SMTP; 15 Oct 2002 06:34:21 -0000 X-Priority: 3 X-MSMail-Priority: Normal Received: (qmail 26396 invoked from network); 15 Oct 2002 06:34:40 -0000 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Received: from post.thorcom.com (193.82.116.70) by warrior.services.quay.plus.net with SMTP; 15 Oct 2002 06:34:40 -0000 Received: from majordom by post.thorcom.com with local (Exim 4.10) id 181LDx-0005FG-00 for rsgb_lf_group-outgoing@blacksheep.org; Tue, 15 Oct 2002 07:30:37 +0100 Received: from [212.164.44.2] (helo=astral.omskcity.com) by post.thorcom.com with esmtp (Exim 4.10) id 181LDw-0005F7-00 for rsgb_lf_group@blacksheep.org; Tue, 15 Oct 2002 07:30:37 +0100 Received: from fitec.omskcity.com (mu05.dialup2.infomsk.ru [212.164.44.117]) by astral.omskcity.com (8.9.3/8.9.3) with SMTP id NAA3dabb56d15e4 for ; Tue, 15 Oct 2002 13:27:57 +0700 (OSS) Date: Tue, 15 Oct 2002 13:26:59 +0000 (GMT) From: "Alexander S. Yurkov" To: rsgb_lf_group@blacksheep.org In-reply-to: Message-ID: MIME-Version: 1.0 Subject: Re: LF: glfer 0.3 for Linux Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed X-Spam-Status: No, hits=-1.1 required=5.0tests=DATE_IN_FUTURE_06_12,EMAIL_ATTRIBUTION,IN_REP_TO, SPAM_PHRASE_00_01,USER_AGENT_PINEversion=2.42 Sender: Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group Hi, Claudio. On Fri, 11 Oct 2002, Claudio Girardi wrote: > I have just finished a new release of glfer, a Linux application combining a > spectrogram viewer and a QRSS/DFCW keyer. As You are working in computer signal processing it seems result of some my reseach (not published) should be interesting for You. Main idea is as folow. Conventional algorithms of signal processing (say FFT) are optimal if noise is Gauss distributed. But is spheric noise Gauss distributed realy? My investigation show that this is wrong. Really spheric noise (QRN) is distributed not by Gauss function exp(-x*x). Much better aproximation is Lorentz function 1/( 1 + x*x). But conventional signal processing is not optimal in such a noise! As it was shown by me optimal signal processing in Lorenz noise require to solve very complex nonlinear integral equation. But if one solve the equation by iteration procedure he get as folows. First iteration yeld conventional linear processing. But next iteration yelds that optimal is not linear filtration of signal but nonlinear instant conversion by a function x/(1 + x*x) and THAN conventional linear processing. Incoming signal level should be controled to give mean noise level equal to 1. So it is very simple to realize! The only addition is input convertion of the incoming signal S1(t) = S(t)/[A + S(t)*S(t)] where S(t) if signal from RX. Parameter A shold be controlled to get best reciption. Than signal S1(t) is processed by conventional procedure (say FFT). It is very interesting to try such an algorithm. 73 de RA9MB/Alex http://www.qsl.net/ra9mb