Return-Path: Received: (qmail 12317 invoked from network); 8 Feb 2002 23:50:56 -0000 Received: from unknown (HELO warrior.services.quay.plus.net) (212.159.14.227) by excalibur-qfe1-smtp-plusnet.harl.plus.net with SMTP; 8 Feb 2002 23:50:56 -0000 X-Priority: 3 X-MSMail-Priority: Normal Received: (qmail 10742 invoked from network); 8 Feb 2002 23:50:54 -0000 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Received: from unknown (HELO post.thorcom.com) (212.172.148.70) by warrior.services.quay.plus.net with SMTP; 8 Feb 2002 23:50:54 -0000 Received: from majordom by post.thorcom.com with local (Exim 3.33 #2) id 16ZKiY-0006Wu-00 for rsgb_lf_group-outgoing@blacksheep.org; Fri, 08 Feb 2002 23:46:10 +0000 Received: from imo-r06.mx.aol.com ([152.163.225.102]) by post.thorcom.com with esmtp (Exim 3.33 #2) id 16ZKiX-0006Wl-00 for rsgb_lf_group@blacksheep.org; Fri, 08 Feb 2002 23:46:09 +0000 Received: from MarkusVester@aol.com by imo-r06.mx.aol.com (mail_out_v32.5.) id l.93.17cd74f6 (16337) for ; Fri, 8 Feb 2002 18:44:45 -0500 (EST) From: MarkusVester@aol.com Message-ID: <93.17cd74f6.2995bcec@aol.com> Date: Fri, 8 Feb 2002 18:44:44 EST Subject: LF: Jason: 65 channels? To: rsgb_lf_group@blacksheep.org MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 8bit X-Mailer: AOL 4.0.i for Windows 95 sub 72 Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group Sender: G'day Alberto, Steve and all, its great to see the concept of FDK and its friendly implementation in Jason. But, one question came to my mind: Instead of using a 4-bit pair for each 6 bit character, why not take it all the way and transmit 6 bits at once? Of course, this would mean 65 frequencies instead of 17, four times the bandwidth at first glance. But then you could double the symbol duration and halve the FFT bin bandwidth to 42 mHz, picking up some SNR on the way. Additionally, even with a Hamming or Bartlett window, the noise in channels only two bins apart should have no significant correlation. Thus the total occupied bandwidth would increase from the current 4.12 Hz to no more than 5.42 Hz. What do you think? 73 de Markus, DF6NM