Return-Path: Received: from mtain-dg04.r1000.mx.aol.com (mtain-dg04.r1000.mx.aol.com [172.29.65.12]) by air-me10.mail.aol.com (v129.4) with ESMTP id MAILINME101-8bc44da19761303; Sun, 10 Apr 2011 07:41:21 -0400 Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-dg04.r1000.mx.aol.com (Internet Inbound) with ESMTP id 5971C3800009E; Sun, 10 Apr 2011 07:41:19 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1Q8szm-000364-OO for rs_out_1@blacksheep.org; Sun, 10 Apr 2011 12:39:58 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1Q8szm-00035v-97 for rsgb_lf_group@blacksheep.org; Sun, 10 Apr 2011 12:39:58 +0100 Received: from mout2.freenet.de ([195.4.92.92]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1Q8szl-0000F3-7F for rsgb_lf_group@blacksheep.org; Sun, 10 Apr 2011 12:39:58 +0100 Received: from [195.4.92.17] (helo=7.mx.freenet.de) by mout2.freenet.de with esmtpa (ID dl4yhf@freenet.de) (port 25) (Exim 4.72 #5) id 1Q8szk-0004J5-6R for rsgb_lf_group@blacksheep.org; Sun, 10 Apr 2011 13:39:56 +0200 Received: from blfd-4db0fad1.pool.mediaways.net ([77.176.250.209]:1943 helo=[192.168.0.101]) by 7.mx.freenet.de with esmtpsa (ID dl4yhf@freenet.de) (TLSv1:CAMELLIA256-SHA:256) (port 465) (Exim 4.72 #3) id 1Q8szk-00031G-1U for rsgb_lf_group@blacksheep.org; Sun, 10 Apr 2011 13:39:56 +0200 Message-ID: <4DA1970A.2050802@freenet.de> Date: Sun, 10 Apr 2011 13:39:54 +0200 From: wolf_dl4yhf User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; de; rv:1.9.2.15) Gecko/20110303 Thunderbird/3.1.9 MIME-Version: 1.0 To: rsgb_lf_group@blacksheep.org References: <4DA02769.9090003@talktalk.net> <4DA0B615.8060502@iup.uni-heidelberg.de> <4DA0BF27.9020705@talktalk.net> <4DA0C3DB.5000509@iup.uni-heidelberg.de> <4DA169F0.70506@freenet.de> <4DA18B81.4060807@iup.uni-heidelberg.de> In-Reply-To: <4DA18B81.4060807@iup.uni-heidelberg.de> X-Spam-Score: 1.4 (+) X-Spam-Report: autolearn=disabled,RATWARE_GECKO_BUILD=1.426 Subject: GPS Sync (was: Re: LF: Wow 8.9696kHzOssi?) Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.0 required=5.0 tests=none 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-global-disposition: G x-aol-sid: 3039ac1d410c4da1975e0e70 X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none X-Mailer: Unknown (No Version) Hello Stefan, Yes, the charm of the GPS-sync'd sampling is that it allows truly coherent transmission - even after the program was shortly stopped, PC rebooted, generator re-fuelled, or whatever strange things may happen. The sine wave generator will (optionally) not calculate the argument based on the number of soundcard samples, but derived from the GPS-derived time of day. Which, with the GPS 18x LVC mentioned before, seems to have a resolution (not neccessarily a precision) in the sub-microsecond range (192 kHz SR -> 5.x microsecond samples, but internally interpolated to a higher sample rate near the slope of the sync pulse). At 192 kHz sampling rate, I get a standard deviation in the measured pulse position of only 30 to 60 nanoseconds (per one-second-interval) measured over one minute, which almost sounds too good to be true. Thus i'm a bit sceptic, this needs more testing. Some preliminary info about the GPS-based calibration is already available here: http://www.qsl.net/dl4yhf/speclab/frqcalib.htm#gps_pps_output Note: The NMEA decoder for the soundcard is not implemented in the SL version on my website. It will be implemented when the weather(!) permits ;-) 73, Wolf DL4YHF (off for a walk now..)