Return-Path: Received: from rly-me02.mx.aol.com (rly-me02.mail.aol.com [172.20.83.35]) by air-me03.mail.aol.com (v123.3) with ESMTP id MAILINME032-99f49b18cd727b; Fri, 06 Mar 2009 15:52:00 -0500 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by rly-me02.mx.aol.com (v123.3) with ESMTP id MAILRELAYINME023-99f49b18cd727b; Fri, 06 Mar 2009 15:51:38 -0500 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1Lfh0i-0001Ck-RS for rs_out_1@blacksheep.org; Fri, 06 Mar 2009 20:51:12 +0000 Received: from [83.244.159.144] (helo=relay3.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1Lfh0i-0001Cb-1D for rsgb_lf_group@blacksheep.org; Fri, 06 Mar 2009 20:51:12 +0000 Received: from smtp5.freeserve.com ([193.252.22.151] helo=smtp6.freeserve.com) by relay3.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1Lfh0g-0005LR-Ju for rsgb_lf_group@blacksheep.org; Fri, 06 Mar 2009 20:51:11 +0000 Received: from me-wanadoo.net (localhost [127.0.0.1]) by mwinf3529.me.freeserve.com (SMTP Server) with ESMTP id 11E371C00084 for ; Fri, 6 Mar 2009 21:51:05 +0100 (CET) Received: from AGB (unknown [91.109.23.203]) by mwinf3529.me.freeserve.com (SMTP Server) with SMTP id 803401C00081 for ; Fri, 6 Mar 2009 21:51:04 +0100 (CET) X-ME-UUID: 20090306205104525.803401C00081@mwinf3529.me.freeserve.com Message-ID: <28FA0F184B25444F8BA2F1EC5FC42C04@AGB> From: "Graham" To: References: <0566EF6DE20B4249A3E74859BF9BA2C6@AGB> <9C03FBF153AB478A9B0DBC5580CF20D2@AGB> In-Reply-To: Date: Fri, 6 Mar 2009 20:51:02 -0000 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal Importance: Normal X-Mailer: Microsoft Windows Live Mail 14.0.8064.206 X-MimeOLE: Produced By Microsoft MimeOLE V14.0.8064.206 X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001 Subject: Re: LF: Multi-function beacon Content-Type: multipart/alternative; boundary="----=_NextPart_000_00D4_01C99E9D.434773A0" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.6 required=5.0 tests=HTML_40_50,HTML_MESSAGE, MISSING_OUTLOOK_NAME 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-AOL-IP: 193.82.116.20 ------=_NextPart_000_00D4_01C99E9D.434773A0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable OK Andy,=20 I was thinking more in terms of generating the pulse using 'audio' and not=20= by hard keying .. but the 'area under the curve' looks a little 'thin' ..p= ity .. the rest of the system could be 'constructed' using a audio editor=20= .and sent via a ssb tx with alc 'off' .. how accurate is the start time req= uirements ?=20 tnx- G ..=20 From: Andy Talbot=20 Sent: Friday, March 06, 2009 8:13 PM To: rsgb_lf_group@blacksheep.org=20 Subject: Re: LF: Multi-function beacon Not strictly -=20 Look at it in th efreqeuncy domain. A 500us pulse has its first zero at 200= 0/pi =3D 637Hz, so most of the energy is within 1300Hz bandwidth, and a subs= tantial part will pass though the Rx filter. It will be extended in time an= d flattenned, but the detection algorithm finds the peak, in effect applying= an inverse transform of the SSB filter. Andy G4JNT www.g4jnt.com Nb the pulse width , 500uS .. that's a bit sharp for a ssb filter , on= ly 1.5 cycles at 3 Khz ... ? ----------------------------------------------------------------------------= ---- No virus found in this incoming message. Checked by AVG - www.avg.com=20 Version: 8.0.237 / Virus Database: 270.11.8/1987 - Release Date: 03/06/09 07= :20:00 ------=_NextPart_000_00D4_01C99E9D.434773A0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
OK  Andy,
 
I was thinking more in terms of generating=20 the  pulse using 'audio' and not by hard keying .. but the 'area under=20 the  curve' looks a little 'thin'  ..pity .. the  rest of=20 the  system could be 'constructed' using a audio editor .and sent via a= ssb=20 tx with alc 'off' .. how accurate is the  start time requirements ?=20
 
tnx- G ..
 
 

Sent: Friday, March 06, 2009 8:13 PM
Subject: Re: LF: Multi-function beacon

Not strictly -
Look at it in th efreqeuncy domain.  A 500us pulse has its first z= ero=20 at 2000/pi =3D 637Hz, so most of the energy is within 1300Hz bandwidth, and&= nbsp;a=20 substantial part will pass though the Rx filter.  It will be extended i= n=20 time and flattenned, but the detection algorithm finds the peak, in effect=20 applying an inverse transform of the SSB filter.

Andy  G4JNT
= www.g4jnt.com

 
 
Nb   the  pulse width , 500uS .= . that's=20 a bit  sharp for a ssb filter , only  1.5 cycles at 3 Khz ....=20 ?
 
 
 
 


No virus found in this incoming message.
Checked by AVG -=20 www.avg.com
Version: 8.0.237 / Virus Database: 270.11.8/1987 - Release D= ate:=20 03/06/09 07:20:00
------=_NextPart_000_00D4_01C99E9D.434773A0--