Return-Path: Received: (qmail 847 invoked from network); 23 Jan 2001 18:03:11 -0000 Received: from unknown (HELO murphys-inbound.servers.plus.net) (212.159.14.225) by excalibur.plus.net with SMTP; 23 Jan 2001 18:03:10 -0000 Received: (qmail 19159 invoked from network); 23 Jan 2001 17:57:25 -0000 Received: from unknown (HELO post.thorcom.com) (212.172.148.70) by murphys with SMTP; 23 Jan 2001 17:57:25 -0000 Received: from majordom by post.thorcom.com with local (Exim 3.16 #1) id 14L7UO-0001lU-00 for rsgb_lf_group-outgoing@blacksheep.org; Tue, 23 Jan 2001 17:44:16 +0000 Received: from [200.231.181.97] (helo=ntweb.globocabo.com.br) by post.thorcom.com with esmtp (Exim 3.16 #1) id 14L7UM-0001lP-00 for rsgb_lf_group@blacksheep.org; Tue, 23 Jan 2001 17:44:15 +0000 Received: from spovdesi1625 (SPOVD-ESI-1625 [5.8.10.82]) by ntweb.globocabo.com.br with SMTP (Microsoft Exchange Internet Mail Service Version 5.5.2653.13) id D3JJ1V19; Tue, 23 Jan 2001 15:39:51 -0300 Message-ID: <011901c0856b$e3dbc680$520a0805@globocabo.com.br> From: "PY3CRX PY2PLL" To: "LF Group" References: <200101222330.VAA19729@mozart.unetsul.com.br> <3A6D9131.93205719@usa.net> Subject: Re: LF: Sound Card Accuracy Date: Tue, 23 Jan 2001 16:39:43 -0200 MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1; format=flowed Content-Transfer-Encoding: 8bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 5.50.4133.2400 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group Sender: Hi Alberto ... > > value = 11024,80450540374 . > > > > A long number but reflects what I see on most softwares that don't > > have offset adjustments. An 800Hz tone is measured as 796,4Hz ... > How can you have a 0.2 Hz error at 11025 Hz and then 3.6 Hz at 800 Hz ? > Or did I understand wrongly your numbers ? This 11.024XXX divided by 2 is the "corrected clock value" that JVComm32 needs to print a straight vertical line when in HF-FAX mode , 60 lines per minute. It's not some measured reference value. The procedure was: - JVcomm using 11025 as default sampling rate and 60LPM mode. - WWV or GPS 1pps pulse to receiver. - Some minutes later I had a slanted line, which reveals the sound card clock inaccuracy. - Applying the "slant correction", software pop-up an info "I'll set the clock value as 11.024XXX/2". That's it. W95SSTV needed offset at the same "direction". But this software doesn't show the adopted value. Other numbers for the same "800Hz" tone: = Analyzer2000 measured 796,4Hz. = Argo measured 802,25 Hz - don't remember the decimal portion = Freq Counter measured 798.8 <> 801.6 - alternating = Spectran 127 , 8KHz sampling rate, needed -6.7Hz offset to show 800.0 Hz = PSK31 for SB16 gave -5 degree (AFC off) - (6 degree = 1 hz?) I have K6STI DSP-Blaster with its I/Q vector display, SbFFT1.2 from KW5Q, Spectrum for EVM (G3PLX). I'll do some measurements tonight to see what I got. Question: the modulating tones used by WWV HF signal are accurate? How much? 73 Marcus PY3CRX/PY2PLL S. B. do Campo - GG66rf http://py.qsl.br Active from "DC" to 24GHz