Return-Path: Received: (qmail 66707 invoked from network); 12 Dec 2003 11:26:28 -0000 Received: from unknown (HELO netmail00.services.quay.plus.net) (212.159.14.218) by ptb-mailstore with SMTP; 12 Dec 2003 11:26:28 -0000 Received: (qmail 8071 invoked from network); 12 Dec 2003 11:26:27 -0000 X-Filtered-by: Plusnet (hmail v1.01) X-Spam-detection-level: 11 Received: from post.thorcom.com (193.82.116.20) by netmail00.services.quay.plus.net with SMTP; 12 Dec 2003 11:26:22 -0000 X-Fake-Domain: majordom Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1AUlQP-0006YO-I8 for rs_out@blacksheep.org; Fri, 12 Dec 2003 11:25:37 +0000 Received: from [147.197.200.9] (helo=hestia.herts.ac.uk) by post.thorcom.com with esmtp (Exim 4.14) id 1AUlQO-0006YF-ST for rsgb_lf_group@blacksheep.org; Fri, 12 Dec 2003 11:25:36 +0000 X-Fake-Domain: gemini Received: from gemini ([147.197.200.44] helo=gemini.herts.ac.uk) by hestia.herts.ac.uk with esmtp (Exim 3.22 #1) id 1AUlIY-0005rE-00 for rsgb_lf_group@blacksheep.org; Fri, 12 Dec 2003 11:17:30 +0000 X-No-DNS-For: 147.197.232.252 Received: from [147.197.232.252] (helo=rsch15) by gemini.herts.ac.uk with esmtp (Exim 3.33 #1) id 1AUlIW-0003Cj-00 for rsgb_lf_group@blacksheep.org; Fri, 12 Dec 2003 11:17:28 +0000 From: "James Moritz" To: rsgb_lf_group@blacksheep.org Date: Fri, 12 Dec 2003 11:17:28 -0000 Organization: University of Hertfordshire X-Bad-Message-ID: no DNS (rsch15) Message-ID: <000001c3c0a1$86f819e0$fce8c593@rsch15> MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.2627 Importance: Normal In-reply-to: <001901c3c00d$5c321600$045bfea9@RSGB613192> X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 X-UH-MailScanner: No Virus detected Subject: RE: LF: Related Technical Query - Soundcard calibrator Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 8bit X-Spam-Checker-Version: SpamAssassin 2.60 (1.212-2003-09-23-exp) on post.thorcom.com X-Spam-Status: No, hits=0.0 required=5.0 tests=none autolearn=no version=2.60 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: rs_out@blacksheep.org X-SA-Exim-Scanned: No; SAEximRunCond expanded to false X-Spam-Rating: 2 Dear Andy, LF Group I hate to throw a spanner in the works, but... A noise source of exactly this type is discussed in Horowitz & Hill "The Art of Electronics" 2nd ed., section 9.34. This gives the formula (in the form Andy has used) Vrms^2 = Vpk^2 * 2 * BW /Fclock, (giving 224mV rms) which is different by a factor of sqrt(pi) from the value Andy gets. I spent some time last night trying to figure out which one is correct, and came out with a reasonably convincing case for Horowitz & Hill's formula - if anyone is interested, I will put it into an e-mail compatible form Cheers, Jim Moritz 73 de M0BMU