Return-Path: Received: (qmail 28910 invoked from network); 8 Dec 2000 17:44:08 -0000 Received: from unknown (HELO warrior-inbound.servers.plus.net) (212.159.14.227) by excalibur.plus.net with SMTP; 8 Dec 2000 17:44:08 -0000 Received: (qmail 3196 invoked from network); 8 Dec 2000 17:39:06 -0000 Received: from unknown (HELO post.thorcom.com) (212.172.148.70) by warrior with SMTP; 8 Dec 2000 17:39:06 -0000 Received: from majordom by post.thorcom.com with local (Exim 3.16 #1) id 144RKQ-0008SW-00 for rsgb_lf_group-outgoing@blacksheep.org; Fri, 08 Dec 2000 17:29:02 +0000 Received: from fep02.swip.net ([130.244.199.130] helo=fep02-svc.swip.net) by post.thorcom.com with esmtp (Exim 3.16 #1) id 144RKM-0008SM-00 for rsgb_lf_group@blacksheep.org; Fri, 08 Dec 2000 17:28:58 +0000 Received: from oemcomputer ([212.151.84.161]) by fep02-svc.swip.net (InterMail vM.5.01.01.01 201-252-104) with SMTP id <20001208172814.NHT1660.fep02-svc.swip.net@oemcomputer> for ; Fri, 8 Dec 2000 18:28:14 +0100 Message-ID: <004001c0613c$4d26e2e0$a15497d4@oemcomputer> From: "Johan Bodin" To: rsgb_lf_group@blacksheep.org Subject: LF: SV: CRUNCH method Date: Fri, 8 Dec 2000 18:27:45 +0100 MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1; format=flowed Content-Transfer-Encoding: 8bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 4.72.3110.5 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group Sender: Hi >Decimation to lower the sampling rate is straightforward if wanted, >just by taking one sample out of every N. You'll need a decimation filter to keep aliases out if the original signal has spectral components that are above the decimated Fs/2 (Nyquist!). One way to accomplish this is to feed the original signal into the circular buffer of a FIR filter of suitable design, at the original Fs, and then compute the filter output at the decimated output Fs. 73 Johan SM6LKM