Return-Path: <owner-rsgb_lf_group@blacksheep.org>
Received: (qmail 16410 invoked from network); 19 Nov 2002 00:42:27 -0000
Received: from murphys.services.quay.plus.net (212.159.14.225)  by mailstore with SMTP; 19 Nov 2002 00:42:27 -0000
Received: (qmail 9155 invoked from network); 19 Nov 2002 00:41:51 -0000
X-Priority: 3
X-MSMail-Priority: Normal
Received: from post.thorcom.com (193.82.116.70)  by murphys.services.quay.plus.net with SMTP; 19 Nov 2002 00:41:51 -0000
X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106
X-SQ: A
Received: from majordom by post.thorcom.com with local (Exim 4.10) id 18DwP7-0003SE-00 for rsgb_lf_group-outgoing@blacksheep.org; Tue, 19 Nov 2002 00:38:13 +0000
Received: from [165.212.11.111] (helo=cmsoutbound.mx.net) by post.thorcom.com with smtp (Exim 4.10) id 18DwP7-0003S5-00 for rsgb_lf_group@blacksheep.org; Tue, 19 Nov 2002 00:38:13 +0000
Received: from uadvg128.cms.usa.net (HELO localhost) (165.212.11.128)  by cmsoutbound.mx.net with SMTP; 19 Nov 2002 00:38:04 -0000
Received: from usa.net [213.217.179.68] by uadvg128.cms.usa.net (ASMTP/dibene@usa.net) via mtad (C8.MAIN.1.09A)  with ESMTP id 325gksaMa0139M28; Tue, 19 Nov 2002 00:38:00 GMT
Message-ID: <3DD97FE9.7000607@usa.net>
Date: Tue, 19 Nov 2002 01:03:53 +0100
From: "Alberto di Bene" <dibene@usa.net>
User-Agent: Mozilla/5.0 (Windows; U; Win98; en-US; rv:1.0.1) Gecko/20020823 Netscape/7.0
X-Accept-Language: en-us, en
MIME-Version: 1.0
To: rsgb_lf_group@blacksheep.org
References: <3DD6356A.8070000@usa.net> <3DD7D1A3.20509@usa.net> <3DD8A702.FDAA16E2@otenet.gr>
Subject: Re: LF: Argo V1 build 130 released
Content-Type: text/plain; charset=ISO-8859-7; format=flowed
Content-Transfer-Encoding: 8bit
X-Spam-Status: No, hits=-3.3 required=5.0tests=DEAR_SOMEBODY,EMAIL_ATTRIBUTION,QUOTED_EMAIL_TEXT,      REFERENCES,SPAM_PHRASE_00_01,USER_AGENT,      USER_AGENT_MOZILLA_UA,X_ACCEPT_LANGversion=2.42
Sender: <owner-rsgb_lf_group@blacksheep.org>
Precedence: bulk
Reply-To: rsgb_lf_group@blacksheep.org
X-Listname: rsgb_lf_group

Alex Deligiannis wrote:

>Dear Alberto,
>                     V1.130 running here OK but I have a question about
>Spectran V1 which I use more than Argo. I found a difference of 110 to 120 mH
>between Argo readings and Spectran as follows:
>
>MSF >     Argo 799.73 Hz  Spectran  799.84 Hz
>
>HBG >     Argo 799.71 Hz  Spectran  799.84 Hz   and
>
>DCF77 > Argo 799.71 Hz   Spectran 799.84  Hz  (all CW mode 800 HZ pitch)
>
>I'm wandering why I have this difference between the two programs and second
>how I can calibrate  spectran.
>  
>
Dear Alex,
   there are a couple of things to consider.  First, the program 
settings. The FFT bins are
spaced according to the FFT length and sampling rate chosen, and the 
peak indicated
is that of the nearest bin. So you should compare Argo and Spectran at 
the same FFT
length and sampling rate. Spectran reports in its control panel those 
values, Argo doesn't.
Argo, when in horizontal mode, uses 5512 as sampling rate and FFT 
lengths as follows :

QRSS3  :   16384
QRSS10 :  65536
QRSS20 :  131072
QRSS30 :  262144     etc. etc.

But there is a second point to consider : when I said that the nearest 
bin is used for
indicating the peak frequency, I cheated a little. That is true for 
Spectran.
In Argo I tried to be a bit smarter... the peak indicated is computed 
with a
quadratic interpolation of three adjacent bins, the highest magnitude 
one and its two
neighbours,  using their relative magnitudes as weights.
So, all in all, may be Argo is a tad more precise than Spectran, at 
least at comparable
resolutions.

As for calibration, the current version of Spectran doesn't have that 
facility. May be
in a forthcoming one...

73  Alberto  I2PHD