Return-Path: X-Spam-DCC: paranoid 1290; 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 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 u0VKqMMD031744 for ; Sun, 31 Jan 2016 21:52:22 +0100 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1aPyuw-0006K9-7e for rs_out_1@blacksheep.org; Sun, 31 Jan 2016 20:48:18 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1aPyuv-0006K0-G0 for rsgb_lf_group@blacksheep.org; Sun, 31 Jan 2016 20:48:17 +0000 Received: from brian.netcom.co.uk ([217.72.171.64]) by relay1.thorcom.net with esmtp (Exim 4.86) (envelope-from ) id 1aPytr-0001vH-BP for rsgb_lf_group@blacksheep.org; Sun, 31 Jan 2016 20:48:16 +0000 Received: from sb.abelian.org (i-194-106-52-83.freedom2surf.net [194.106.52.83]) by brian.netcom.co.uk (Postfix) with ESMTP id D5755320078 for ; Sun, 31 Jan 2016 20:25:44 +0000 (GMT) Received: from [127.0.0.1] (localhost [127.0.0.1]) by sb.abelian.org (Postfix) with ESMTP id 8767928A0210 for ; Sun, 31 Jan 2016 20:46:54 +0000 (UTC) Message-ID: <56AE72BE.9080308@abelian.org> Date: Sun, 31 Jan 2016 20:46:54 +0000 From: Paul Nicholson User-Agent: Mozilla/5.0 (X11; Linux i686; rv:17.0) Gecko/20130106 Thunderbird/17.0.2 MIME-Version: 1.0 To: "rsgb_lf_group@blacksheep.org" X-Scan-Signature: 2e2f7cbbe9f38dd7bf3fac4fc012e6fc Subject: LF: Linux DDS program Content-Type: text/plain; charset=ISO-8859-1; 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 10.1.3.10 Status: RO X-Status: X-Keywords: X-UID: 6588 Here's a DDS program for Linux PC and Raspberry Pi, http://abelian.org/ebnaut/ebsynth.shtml Intended for sending EbNaut but can be used as a standalone signal generator. I've been testing it in the near field at VLF and it works well, reliable sending EbNaut down to 50mS symbols. I wonder if it will work at LF using the 3rd harmonic? I haven't tried that yet. The program uses the Goertzel algorithm to track the phase and frequency of the reference signal and outputs a sine wave which is in some fixed frequency ratio to the reference. The output is phase and frequency locked. The phase jitter is small and difficult to measure when the program is running on a 192k/sec PCI soundcard. It hasn't had a huge amount of testing so consider it a 'beta' but it seems to work well so I thought I'd share it. -- Paul Nicholson --