Return-Path: <majordom@post.thorcom.com> Received: (qmail 7475 invoked from network); 2 Jan 2002 20:42:32 -0000 Received: from unknown (HELO murphys-inbound.services.quay.plus.net) (212.159.14.225) by excalibur.plus.net with SMTP; 2 Jan 2002 20:42:32 -0000 Received: (qmail 21006 invoked from network); 2 Jan 2002 20:42:32 -0000 Received: from unknown (HELO post.thorcom.com) (212.172.148.70) by murphys.services.quay.plus.net with SMTP; 2 Jan 2002 20:42:32 -0000 Received: from majordom by post.thorcom.com with local (Exim 3.33 #2) id 16Ls8H-0007LY-00 for rsgb_lf_group-outgoing@blacksheep.org; Wed, 02 Jan 2002 20:37:05 +0000 Received: from mailman.zeta.org.au ([203.26.10.16]) by post.thorcom.com with esmtp (Exim 3.33 #2) id 16Ls8F-0007LS-00 for rsgb_lf_group@blacksheep.org; Wed, 02 Jan 2002 20:37:04 +0000 Received: from steve (ppp203.dyn154.pacific.net.au [210.23.154.203]) by mailman.zeta.org.au (8.9.3/8.8.7) with SMTP id HAA23849 for <rsgb_lf_group@blacksheep.org>; Thu, 3 Jan 2002 07:36:12 +1100 Message-ID: <007301c193cd$ebb87e40$cb9a17d2@steve> From: "Steve Olney" <ollaneg@zeta.org.au> To: rsgb_lf_group@blacksheep.org References: <194.97dafc.2963ca43@aol.com> Subject: Re: LF: Very slow DFCW Date: Thu, 3 Jan 2002 07:41:47 +1100 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 5.00.2314.1300 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: <majordom@post.thorcom.com> G'day Wolf, I have been trying to understand the information you gave as below:- > >Using these settings to receive: > Sample rate = 11025 Hz > FFT type = complex, center frequency = 650 Hz (preferred "AF IF") > FFT decimation = 128 > FFT input size = 16384 > FFT resolution = 5.3 milliHertz > Waterfall scroll rate = 30 seconds > I am interested to learn how you get the 5.3mHz resolution. From my understanding the resolution of an FFT of 16384 samples at sample rate 11025Hz would be - 11025/16384 = 0.673Hz. By decimating in time 128 records (and averaging) I thought there is no gain in resolution, but you get an increase in S/N of sqrt(128) in each of these 0.673Hz bins. How are the 5.3mHz bins generated ? 73s Steve Olney (VK2ZTO/AXSO - QF56IK : Lat -33 34 07, Long +150 44 40) ============================================= HomePage URL: http://www.zeta.org.au/~ollaneg Containing:- ULF, ELF, VLF & LF Experimentation MF 22m Experimentation InfraSonic Experimentation Laser Comms DX =============================================