Return-Path: Received: (qmail 23825 invoked from network); 25 Apr 2003 16:11:25 -0000 Received: from warrior.services.quay.plus.net (212.159.14.227) by mailstore with SMTP; 25 Apr 2003 16:11:25 -0000 X-Priority: 3 X-MSMail-Priority: Normal Received: (qmail 24467 invoked from network); 25 Apr 2003 16:04:07 -0000 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Received: from post.thorcom.com (193.82.116.70) by warrior.services.quay.plus.net with SMTP; 25 Apr 2003 16:04:07 -0000 X-SQ: A Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1995fO-00066k-Dp for rsgb_lf_group-outgoing@blacksheep.org; Fri, 25 Apr 2003 17:03:14 +0100 Received: from [152.163.225.104] (helo=imo-r08.mx.aol.com) by post.thorcom.com with esmtp (Exim 4.14) id 1995fH-00066V-S1 for rsgb_lf_group@blacksheep.org; Fri, 25 Apr 2003 17:03:07 +0100 Received: from DL4YHF@aol.com by imo-r08.mx.aol.com (mail_out_v34.22.) id l.1ed.76fc965 (30970) for ; Fri, 25 Apr 2003 12:02:31 -0400 (EDT) From: DL4YHF@aol.com Message-ID: <1ed.76fc965.2bdab616@aol.com> Date: Fri, 25 Apr 2003 12:02:30 EDT To: rsgb_lf_group@blacksheep.org MIME-Version: 1.0 X-Mailer: 6.0 for Windows XP sub 50 Subject: Re: LF: RE: something for the weekend ?? Content-Type: text/html; charset=windows-1252 X-Spam-Status: No, hits=2.2 required=5.0tests=HTML_20_30,HTML_MESSAGE,MIME_LONG_LINE_QP,NO_REAL_NAMEversion=2.53 X-Spam-Level: ** X-Spam-Checker-Version: SpamAssassin 2.53 (1.174.2.15-2003-03-30-exp) X-SA-Exim-Scanned: Yes Sender: Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group X-SA-Exim-Rcpt-To: rsgb_lf_group-outgoing@blacksheep.org X-SA-Exim-Scanned: No; SAEximRunCond expanded to false Content-transfer-encoding: 8bit Hi Andy and group,

forgotten to mention this in my questionable explanation:
For "adding" the 90° phase shift in the sin() and cos() arguments, it's most important that the arguments are positive, which is the case in
   2*cos(a)*sin(b)
but not necessarily in
   sin(a+b)-sin(a-b) .
With a = 2*pi*f_signal * t    and b = 2 * pi * f_lo * t,
(a-b) can be a negative value which gives the wrong phase offset when ADDING 90° = pi/2 .

Cheers,
 Wolf.