Return-Path: Received: (qmail 13286 invoked from network); 6 Mar 2005 00:13:53 -0000 Received: from unknown (HELO ptb-spamcore02.plus.net) (192.168.71.3) by ptb-mailstore02.plus.net with SMTP; 6 Mar 2005 00:13:53 -0000 Received: from mailnull by ptb-spamcore02.plus.net with spamcore-l-b (Exim 4.32; FreeBSD) id 1D7jRb-000Mos-8n for dave@picks.force9.co.uk; Sun, 06 Mar 2005 00:16:27 +0000 Received: from [192.168.67.3] (helo=ptb-mxcore03.plus.net) by ptb-spamcore02.plus.net with esmtp (Exim 4.32; FreeBSD) id 1D7jRb-000Moo-1q for dave@picks.force9.co.uk; Sun, 06 Mar 2005 00:16:27 +0000 Received: from post.thorcom.com ([193.82.116.20]) by ptb-mxcore03.plus.net with esmtp (Exim) id 1D7jR1-0002zc-9S for dave@picks.force9.co.uk; Sun, 06 Mar 2005 00:15:51 +0000 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1D7jOB-00045G-JH for rs_out_1@blacksheep.org; Sun, 06 Mar 2005 00:12:55 +0000 Received: from [193.82.116.30] (helo=relay.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1D7jOB-000457-37 for rsgb_lf_group@blacksheep.org; Sun, 06 Mar 2005 00:12:55 +0000 Received: from cmsout03.mbox.net ([165.212.64.33]) by relay.thorcom.net with esmtp (Exim 4.43) id 1D7jO9-0004pJ-E1 for rsgb_lf_group@blacksheep.org; Sun, 06 Mar 2005 00:12:55 +0000 Received: from cmsout03.mbox.net (cmsout03.mbox.net [165.212.64.33]) by cmsout03.mbox.net (Postfix) with ESMTP id B099047 for ; Sun, 6 Mar 2005 00:12:46 +0000 (GMT) Received: from uadvg137.cms.usa.net [165.212.11.137] by cmsout03.mbox.net via smtad (C8.MAIN.3.21U); Sun, 06 Mar 2005 00:12:46 GMT X-USANET-Source: 165.212.11.137 IN dibene@usa.net uadvg137.cms.usa.net X-USANET-MsgId: XID685JcFamU5824X03 Received: from [81.211.138.65] [81.211.138.65] by uadvg137.cms.usa.net (ASMTP/dibene@usa.net) via mtad (C8.MAIN.3.21E) with ESMTP id 311JcFamS0186M37; Sun, 06 Mar 2005 00:12:44 GMT X-USANET-Auth: 81.211.138.65 AUTH dibene@usa.net [81.211.138.65] Message-ID: <422A4AF1.1020601@usa.net> Date: Sun, 06 Mar 2005 01:12:33 +0100 From: Alberto di Bene User-Agent: Mozilla Thunderbird 1.0 (Windows/20041206) X-Accept-Language: en-us, en MIME-Version: 1.0 To: rsgb_lf_group@blacksheep.org References: <1b8.e4fa61a.2f5b5d7c@aol.com> In-Reply-To: <1b8.e4fa61a.2f5b5d7c@aol.com> X-Enigmail-Version: 0.89.5.0 X-Enigmail-Supports: pgp-inline, pgp-mime Z-USANET-MsgId: XID311JcFamt0186X37 X-SPF-Result: relay.thorcom.net: 165.212.64.33 is neither permitted nor denied by domain of usa.net X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=failed,none Subject: LF: Re: Slow mode comparisons Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 8bit X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Status: No, hits=0.0 required=5.0 tests=none autolearn=no version=2.63 X-SA-Exim-Scanned: Yes Sender: owner-rsgb_lf_group@blacksheep.org Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group X-SA-Exim-Rcpt-To: rs_out_1@blacksheep.org X-SA-Exim-Scanned: No; SAEximRunCond expanded to false X-Spam-Filtered: by PlusNet SpamCORE (v3.00) MarkusVester@aol.com wrote: > My half-penny's worth is that the transmitted energy per symbol is 3.3 > times larger, giving exactly 5.23 dB improvement ;-) That's assuming > that the FFT bandwidth is somewhere near the optimum (0.3 Hz and 0.1 > Hz respectively). Markus, you are correct, but in an ideal situation. Given that for performance reasons the FFT works at its best when done on a sample length which is a power of two, in Argo, when going from QRSS3 to QRSS10 I multiply the sample length by four, which causes a reduction of four times of the bin size. This has the consequence that the noise energy that falls into a single bin is 6 dB lower, hence the 6 dB gain in SNR. There are algorithms to perform FFTs on arbitrary sizes, but they are slower than when working with powers of two. 73 Alberto I2PHD