Return-Path: Received: (qmail 22830 invoked from network); 30 Nov 2002 13:34:45 -0000 Received: from warrior.services.quay.plus.net (212.159.14.227) by mailstore with SMTP; 30 Nov 2002 13:34:45 -0000 X-Priority: 3 X-MSMail-Priority: Normal Received: (qmail 9292 invoked from network); 30 Nov 2002 13:34:36 -0000 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Received: from post.thorcom.com (193.82.116.70) by warrior.services.quay.plus.net with SMTP; 30 Nov 2002 13:34:36 -0000 X-SQ: A Received: from majordom by post.thorcom.com with local (Exim 4.10) id 18I7kn-000100-00 for rsgb_lf_group-outgoing@blacksheep.org; Sat, 30 Nov 2002 13:33:53 +0000 Received: from [152.163.225.103] (helo=imo-r07.mx.aol.com) by post.thorcom.com with esmtp (Exim 4.10) id 18I7km-0000zr-00 for rsgb_lf_group@blacksheep.org; Sat, 30 Nov 2002 13:33:52 +0000 Received: from MarkusVester@aol.com by imo-r07.mx.aol.com (mail_out_v34.13.) id l.170.17d27e8b (3924) for ; Sat, 30 Nov 2002 08:33:18 -0500 (EST) From: MarkusVester@aol.com Message-ID: <170.17d27e8b.2b1a181e@aol.com> Date: Sat, 30 Nov 2002 08:33:18 EST To: rsgb_lf_group@blacksheep.org MIME-Version: 1.0 X-Mailer: AOL 7.0 for Windows DE sub 10501 Subject: Re: LF: Osc drift (TCXO) Content-Type: text/html; charset=windows-1252 X-Spam-Status: No, hits=1.9 required=5.0tests=NO_REAL_NAME,SPAM_PHRASE_00_01,USER_AGENT_AOLversion=2.42 X-Spam-Level: * Sender: Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group Content-transfer-encoding: 8bit Hi,

In a message dated 11/29/02 7:03:23 PM GMT Standard Time, blanch@pncl.co.uk writes:

Layout of the IIG oscillator/synthesizer board is quite different from the
II, also the TCXO for the IIG is much bigger and a different part number.
The TCXO for the II is claimed to be a "numerically-controlled" type, that
for the IIG is not. Does anyone know the difference? I thought all tcxo's
were just thermistor-controlled varactor diodes in series with the crystal.


I think the idea of a numerically-controlled TCXO is having an internal ADC digitizing the NTC voltage, convert it in a calibrated nonvolatile lookup-table and then use a DAC for the varicap. Depending on digital resolution, this concept can be prone to a stepwise response to gradual temperature changes, possibly resulting in a sawtooth FM pattern.

73
Markus, DF6NM