Return-Path: X-Spam-DCC: paranoid 1233; Body=2 Fuz1=2 Fuz2=2 X-Spam-Checker-Version: SpamAssassin 3.1.3 (2006-06-01) on lipkowski.org X-Spam-Level: X-Spam-Status: No, score=-0.5 required=5.0 tests=BAYES_00,DNS_FROM_AHBL_RHSBL, FORGED_RCVD_HELO,RATWARE_GECKO_BUILD,SPF_PASS autolearn=no version=3.1.3 Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by paranoid.lipkowski.org (8.13.7/8.13.7) with ESMTP id u9UFMgPY008559 for ; Sun, 30 Oct 2016 16:22:42 +0100 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1c0rsT-0003Dk-Cm for rs_out_1@blacksheep.org; Sun, 30 Oct 2016 15:18:29 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1c0rsS-0003Db-Qh for rsgb_lf_group@blacksheep.org; Sun, 30 Oct 2016 15:18:28 +0000 Received: from porthos.netcom.co.uk ([217.72.171.73]) by relay1.thorcom.net with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.87) (envelope-from ) id 1c0rsQ-0007ch-C6 for rsgb_lf_group@blacksheep.org; Sun, 30 Oct 2016 15:18:27 +0000 X-DKIM-Result: Domain=abelian.org Result=Signature OK DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=abelian.org ; s=default; h=Content-Transfer-Encoding:Content-Type:In-Reply-To: MIME-Version:Date:Message-ID:From:References:To:Subject:Sender:Reply-To:Cc: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=mqOzROB9Er99WNSXOSYCFMNYmqLj1sYzF6g8WT7YdQc=; b=7vyYl7d8btTcnJjTR0Ggks719O 0evyrvlHLk4y7JicPtFwHaNh5q0aHL6lxty3gE4SQkAgCl3pV7l5y7Hg0XFi/w7RpXMSRmpJHFAyl TSCOEWPeKL3toFlcBSSGsLqGIV1XAIbAPLfxpClqoiQgYAf31egUxh3QXLw4qR/mzlSI=; Received: from i-194-106-52-83.freedom2surf.net ([194.106.52.83]:38484 helo=pn.abelian.org) by porthos.netcom.co.uk with esmtpsa (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.87) (envelope-from ) id 1c0rsN-0002lt-VX for rsgb_lf_group@blacksheep.org; Sun, 30 Oct 2016 15:18:24 +0000 Received: from [127.0.0.1] (localhost [127.0.0.1]) by pn.abelian.org (Postfix) with ESMTP id 524EE400415 for ; Sun, 30 Oct 2016 15:18:23 +0000 (UTC) To: rsgb_lf_group@blacksheep.org References: <157b3bf43d2-111e-bfa3@webprd-a11.mail.aol.com> <0f1b59cf-e10d-1daf-125b-ad4aca471a06@gmail.com> <580205DC.80508@posteo.de> <58020BE2.1020107@posteo.de> <289454467.20161015210855@chriswilson.tv> <5808C23D.6060006@posteo.de> <580CE812.40500@posteo.de> <580CEA96.2010200@posteo.de> <4e343fa907bf9f2652ce9f25fe56d62a@smtp.hushmail.com> <580E12A9.9070309@posteo.de> From: Paul Nicholson Message-ID: <58160F3F.2010600@abelian.org> Date: Sun, 30 Oct 2016 15:18:23 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.8.0 MIME-Version: 1.0 In-Reply-To: X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - porthos.netcom.co.uk X-AntiAbuse: Original Domain - blacksheep.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - abelian.org X-Get-Message-Sender-Via: porthos.netcom.co.uk: authenticated_id: catchall@abelian.org X-Authenticated-Sender: porthos.netcom.co.uk: catchall@abelian.org X-Scan-Signature: 0a4643e586472c13187d293ec5d096c2 Subject: Re: LF: Idiot's guide to receiving Ebnaut? - Tutorial part2 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit 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-Scanned-By: MIMEDefang 2.56 on 10.1.3.11 Status: O X-Status: X-Keywords: X-UID: 9300 Wolf wrote: > measured the standard deviation in the GPS sync pulse > timing. Used an E-MU 0202 at 192 kSamples/second. Ran a quick trial here. With the Trimble 10uS directly into an E-MU 0202 at 192k/sec I get 100nS std dev of the raw intervals. The timing system here uses smoothed intervals which reduces the jitter to below 30nS. Same setup at 48k/sec is useless, the raw std dev is around 6uS. Watching the pulse on vtscope, the waveform changes significantly from one pulse to the next. This is so at both sample rates but seems worse at 48k. Looks like waveshape depends on just when the pulse arrives with respect to the soundcard's internal A/D sampling. With the centroid method, we must avoid sharp edges and flat tops. Some sort of analog filtering before the card input is required. A low pass RC is usually used. I always recommend running the card at its full sample rate and down sample if required after the timing system has done its stuff. -- Paul Nicholson --