Return-Path: Received: (qmail 96721 invoked from network); 12 Dec 2003 18:36:20 -0000 Received: from unknown (HELO murphys.services.quay.plus.net) (212.159.14.225) by ptb-mailstore with SMTP; 12 Dec 2003 18:36:20 -0000 Received: (qmail 3727 invoked from network); 12 Dec 2003 18:36:06 -0000 X-Filtered-by: Plusnet (hmail v1.01) X-Spam-detection-level: 11 Received: from post.thorcom.com (193.82.116.20) by murphys.services.quay.plus.net with SMTP; 12 Dec 2003 18:35:52 -0000 X-Fake-Domain: majordom Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1AUs8d-0004OZ-EG for rs_out@blacksheep.org; Fri, 12 Dec 2003 18:35:43 +0000 Received: from [147.197.200.9] (helo=hestia.herts.ac.uk) by post.thorcom.com with esmtp (Exim 4.14) id 1AUs8c-0004OQ-8o for rsgb_lf_group@blacksheep.org; Fri, 12 Dec 2003 18:35:42 +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 1AUrCc-0003bx-00 for rsgb_lf_group@blacksheep.org; Fri, 12 Dec 2003 17:35:46 +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 1AUrCW-00002M-00 for rsgb_lf_group@blacksheep.org; Fri, 12 Dec 2003 17:35:40 +0000 From: "James Moritz" To: rsgb_lf_group@blacksheep.org Date: Fri, 12 Dec 2003 17:35:40 -0000 Organization: University of Hertfordshire X-Bad-Message-ID: no DNS (rsch15) Message-ID: <000001c3c0d6$5d0419b0$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: <01C3C0B2.09F37E10.g4jnt@thersgb.net> 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, Stewart et al, I have written my noise voltage calculation as a word document. There are plenty of 'pi's in it, but they all disappear by the time you get to the end, which may be good or bad. The word file is about 30kB - I'm not sure, but it may require the equation editor feature of word to be installed to display properly. I also converted it to a pdf file, which by the miracles of data compression came out to be 110kB, but hopefully should display OK. Both are too big for the reflector, so I will send them out separately to whoever asks. I also found the handbook for the HP 3722 pseudo-random noise source, which also gives the result with no pi. It seems that this could produce a calibrated noise source directly for LF with quite ordinary electronics. If you added an oscillator and mixer, it could be used for narrow-band systems over a wider frequency range too. Cheers, Jim Moritz 73 de M0BMU