Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on lipkowski.org X-Spam-Level: X-Spam-Status: No, score=-2.3 required=5.0 tests=FREEMAIL_FORGED_FROMDOMAIN, FREEMAIL_FROM,HEADER_FROM_DIFFERENT_DOMAINS,HTML_MESSAGE,RCVD_IN_DNSWL_MED, SPF_PASS,T_DKIM_INVALID autolearn=ham autolearn_force=no version=3.4.0 X-Spam-DCC: : mailn 1480; Body=2 Fuz1=2 Fuz2=2 Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by lipkowski.org (8.14.4/8.14.4/Debian-8+deb8u1) with ESMTP id v57GAVt0008147 for ; Wed, 7 Jun 2017 18:10:32 +0200 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1dIdMZ-0001s4-4H for rs_out_1@blacksheep.org; Wed, 07 Jun 2017 16:59:15 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1dIdMY-0001rv-C7 for rsgb_lf_group@blacksheep.org; Wed, 07 Jun 2017 16:59:14 +0100 Received: from omr-a017e.mx.aol.com ([204.29.186.68]) by relay1.thorcom.net with esmtps (TLSv1:DHE-RSA-AES256-SHA:256) (Exim 4.89) (envelope-from ) id 1dIdMU-0004uB-OD for rsgb_lf_group@blacksheep.org; Wed, 07 Jun 2017 16:59:13 +0100 Received: from mtaomg-aal01.mx.aol.com (mtaomg-aal01.mx.aol.com [172.27.20.207]) by omr-a017e.mx.aol.com (Outbound Mail Relay) with ESMTP id 6660E3800049 for ; Wed, 7 Jun 2017 11:59:06 -0400 (EDT) Received: from core-acb10h.mail.aol.com (core-acb10.mail.aol.com [172.27.24.10]) by mtaomg-aal01.mx.aol.com (OMAG/Core Interface) with ESMTP id DB6B138000086 for ; Wed, 7 Jun 2017 11:59:04 -0400 (EDT) Received: from 80.146.228.71 by webprd-m73.mail.aol.com (10.74.55.17) with HTTP (WebMailUI); Wed, 07 Jun 2017 11:59:03 -0400 Date: Wed, 7 Jun 2017 11:59:04 -0400 From: Markus Vester To: rsgb_lf_group@blacksheep.org Message-Id: <15c8347d971-adf-3549f@webprd-m73.mail.aol.com> In-Reply-To: <5938152E.2080406@posteo.de> MIME-Version: 1.0 X-MB-Message-Source: WebUI X-MB-Message-Type: User X-Mailer: JAS STD X-Originating-IP: [80.146.228.71] x-aol-global-disposition: G DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=mx.aol.com; s=20150623; t=1496851146; bh=nG7SNwP/M+Vs4BcN9i1X2ajl6U+bhqCQhs2c7sknLbg=; h=From:To:Subject:Message-Id:Date:MIME-Version:Content-Type; b=M/MlakxyRv32rp/M10jJE7Tq8AOLEiT0ueU1lr5qGKopqk7rMookafZhf41hQXXiC INJCxtQzu+PZHRuHk49QGE9aaCjbRCPTDXw37d5IYbKNsEwOas+8PTK9c2GkY562oi BLSu86rOEiUeUrvqiHFNAOFbNlVGrcOIuJqscRKo= x-aol-sid: 3039ac1b14cf593822c8577d X-Scan-Signature: 4ead635eadbaebfaa92cfec77deb715d Subject: LF: Bugfix for ebnaut_ifft utility Content-Type: multipart/alternative; boundary="----=_Part_262518_482832480.1496851143022" 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 2.75 Status: RO X-Status: X-Keywords: X-UID: 11916 ------=_Part_262518_482832480.1496851143022 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Dear EbNauteers, I recently stumbled upon a bug in my ebnaut_ifft3a utility, which is used to convert SpecLab FFT export files to IQ wav files. The first step of the inverse FFT is to take the complex conjugate of the data array. Due to the bug, the respective loop was executed only N-1 times, leaving a sign error in the imaginary part of a single bin next to the center frequency. When fed with a high-SNR signal close to SpecLab's center frequency, this can produce strange undulation patterns in the phase display and a minor SNR degradation for the decoder. The bug has been fixed in version 3b, available on http://df6nm.bplaced.net/VLF/fec_tests/ebnaut_ifft3b.zip Best regards, Markus (DF6NM) ------=_Part_262518_482832480.1496851143022 Content-Type: text/html; charset=utf-8 Content-Transfer-Encoding: 7bit

Dear EbNauteers,

I recently stumbled upon a bug in my ebnaut_ifft3a utility, which is used to convert SpecLab FFT export files to IQ wav files. The first step of the inverse FFT is to take the complex conjugate of the data array. Due to the bug, the respective loop was executed only N-1 times, leaving a sign error in the imaginary part of a single bin next to the center frequency. When fed with a high-SNR signal close to SpecLab's center frequency, this can produce strange undulation patterns in the phase display and a minor SNR degradation for the decoder.

The bug has been fixed in version 3b, available on
 http://df6nm.bplaced.net/VLF/fec_tests/ebnaut_ifft3b.zip

Best regards,
Markus (DF6NM)

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