From owner-freebsd-current@FreeBSD.ORG Sun Mar 6 16:12:03 2011 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 209A91065674 for ; Sun, 6 Mar 2011 16:12:03 +0000 (UTC) (envelope-from erob@gthcfoundation.org) Received: from relais.videotron.ca (relais.videotron.ca [24.201.245.36]) by mx1.freebsd.org (Postfix) with ESMTP id EF5248FC15 for ; Sun, 6 Mar 2011 16:12:02 +0000 (UTC) MIME-version: 1.0 Content-transfer-encoding: 7BIT Content-type: text/plain; charset=ISO-8859-1 Received: from [192.168.0.100] ([184.162.50.38]) by VL-MR-MRZ22.ip.videotron.ca (Sun Java(tm) System Messaging Server 6.3-8.01 (built Dec 16 2008; 32bit)) with ESMTP id <0LHN00G9O902AYA0@VL-MR-MRZ22.ip.videotron.ca> for freebsd-current@freebsd.org; Sun, 06 Mar 2011 11:12:02 -0500 (EST) Message-id: <4D73B23B.9030605@gthcfoundation.org> Date: Sun, 06 Mar 2011 11:11:39 -0500 From: Etienne Robillard Organization: Green Tea Hackers Club User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.1.16) Gecko/20101227 Icedove/3.0.11 To: freebsd-current@freebsd.org X-Enigmail-Version: 1.0.1 Cc: Diane Bruce Subject: Re: can somebody explains OFDM in FreeBSD? X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list Reply-To: erob@gthcfoundation.org List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 06 Mar 2011 16:12:03 -0000 I'm no expert in Wifi or in FFT so I'm forwarding your reply to the list hoping someone with experience with FFT could share lights on OFDM uses of FFT functions below the 30khz range... In other words could FreeBSD be used to control the electromagnetic energy input from out-of-band VLF/ELF waves ? Thanks, On Sun, Mar 06, 2011 at 10:38:30AM -0500, Etienne Robillard wrote: > my best bet is that VLF/ELF frequencies are using FFT (Fast Fourier > Transform) algorithm to increase compression ratio of WLAN devices No. FFT has nothing to do with this. FFT is a mathematical transform. Nothing more, nothing less. > your post mentioned ELF/VLF radiation, thats electromagnetic waves the > frequency range below 30kHz. > > How should a modulation scheme (OFDM) used in the 2.4/5GHz range be > related to radiation in such a low frequency band? It is not. A modulation scheme can be used at any frequency. Nothing to do with the frequency itself. - Diane -- - db@FreeBSD.org db@db.net http://www.db.net/~db