Return-Path: Received: (qmail 570 invoked from network); 18 Jun 1999 16:24:49 +0100 Received: from magnet.plus.net.uk (HELO magnet.force9.net) (195.166.128.26) by guiness.force9.net with SMTP; 18 Jun 1999 16:24:49 +0100 Received: (qmail 7461 invoked from network); 18 Jun 1999 07:31:55 -0000 Received: from unknown (HELO post.thorcom.com) (194.75.130.70) by magnet.plus.net.uk with SMTP; 18 Jun 1999 07:31:55 -0000 Received: from troy.blacksheep.org ([194.75.183.50] ident=root) by post.thorcom.com with esmtp (Exim 2.04 #3) id 10ut2B-0007wR-00; Fri, 18 Jun 1999 08:25:55 +0100 Received: (from root@localhost) by troy.blacksheep.org (8.6.12/8.6.12) id HAA06657 for rsgb_lf_group-outgoing; Fri, 18 Jun 1999 07:24:56 GMT X-Priority: 3 X-MSMail-Priority: Normal Received: from post.thorcom.com (root@post.unica.co.uk [194.75.183.70]) by troy.blacksheep.org (8.6.12/8.6.12) with ESMTP id HAA06653 for ; Fri, 18 Jun 1999 07:24:54 GMT Received: from heavymetal.isys.net ([195.64.96.45] helo=mail1.isys.net) by post.thorcom.com with smtp (Exim 2.04 #3) id 10ut0y-0007v1-00 for rsgb_lf_group@blacksheep.org; Fri, 18 Jun 1999 08:24:40 +0100 Received: from pc [195.64.97.2] by mail1.isys.net with smtp (Exim 1.73 #1) id 10utL8-0003Hr-00; Fri, 18 Jun 1999 09:45:30 +0200 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 From: "Klaus von der Heide" To: rsgb_lf_group@blacksheep.org Date: Fri, 18 Jun 1999 09:25:11 +0200 MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 8bit Subject: LF: Re: Antennas, bandwidth, etc Priority: normal In-reply-to: <199906180116_MC2-79DE-E0E9@compuserve.com> X-Mailer: Pegasus Mail for Win32 (v3.01b) Message-ID: Sender: Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org Hello Lowfwer's Suppression of noise only works well when its behavior is known at the place where the suppression acts. A suppression of pulse type noise by a DSP will work even in the very narrow band case when the impulse response of the system including the antenna is known. The DSP would correlate the incoming signal with some typical noise patterns and subtract this noise correctly in amplitude and phase without cutting off the signal at that time. The typical noise patterns could be identified by the DSP itself. The problem of the narrow band case is that the characteristic steep edges of pulses are filtered out. So the differentiation between gaussian noise, pulses, and signal is difficult. A parallel running broadband receiver would help to locate the pulses. Designing such a noise blanker specially for LF-type noise seems to me a very useful and interesting task. Unfortunately I have null time to do such things on my DSP's before september. Is someone interested? My course on Digital Signal Processing ist available from: http://tech-www.informatik.uni-hamburg.de/Lehre/dsp99/ It is entirely based on MATLAB (Student's Edition) (and Motorola DSP56002EVM). The file dsp.zip contains the whole material. Chapters 13...16 are still in progress. 73 de Klaus, DJ5HG