Return-Path: Received: (qmail 60979 invoked from network); 25 Feb 2004 10:59:35 -0000 Received: from unknown (HELO ptb-mxscan01.plus.net) (212.159.14.235) by ptb-mailstore03.plus.net with SMTP; 25 Feb 2004 10:59:35 -0000 Received: (qmail 83592 invoked from network); 25 Feb 2004 10:59:35 -0000 X-Filtered-by: Plusnet (hmail v1.01) X-Spam-detection-level: 11 Received: from ptb-mxcore01.plus.net (212.159.14.215) by ptb-mxscan01.plus.net with SMTP; 25 Feb 2004 10:59:34 -0000 Received: from post.thorcom.com ([193.82.116.20]) by ptb-mxcore01.plus.net with esmtp (Exim 4.30; FreeBSD) id 1AvwlJ-000LbN-Rw for dave@picks.force9.co.uk; Wed, 25 Feb 2004 10:59:33 +0000 X-Fake-Domain: majordom Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1Avwk7-0006Sl-9H for rs_out@blacksheep.org; Wed, 25 Feb 2004 10:58:19 +0000 Received: from [194.73.73.148] (helo=zinc.btinternet.com) by post.thorcom.com with esmtp (Exim 4.14) id 1Avwk6-0006Sa-NQ for rsgb_lf_group@blacksheep.org; Wed, 25 Feb 2004 10:58:18 +0000 Received: from [81.131.231.92] (helo=Main) by zinc.btinternet.com with smtp (Exim 3.22 #25) id 1Avwk3-0002g6-00 for rsgb_lf_group@blacksheep.org; Wed, 25 Feb 2004 10:58:15 +0000 X-Bad-Message-ID: no DNS (Main) Message-ID: <001901c3fb8e$2f2b4ac0$6507a8c0@Main> From: "Alan Melia" To: rsgb_lf_group@blacksheep.org References: <002601c3f93e$478b35a0$6507a8c0@Main> <001f01c3fb72$f5156750$687a37c0@w2ksn> Date: Wed, 25 Feb 2004 10:41:34 -0000 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 5.50.4522.1200 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Subject: LF: Re: Re: WOLF development Content-Type: text/plain; charset=iso-8859-1; format=flowed Content-Transfer-Encoding: 8bit X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Status: No, hits=0.0 required=5.0 tests=none autolearn=no version=2.63 X-SA-Exim-Scanned: Yes Sender: Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group X-SA-Exim-Rcpt-To: rs_out@blacksheep.org X-SA-Exim-Scanned: No; SAEximRunCond expanded to false X-PN-SPAMFiltered: yes X-Spam-Rating: 2 Hi Stewart,.......answer below...sent direct ----- Original Message ----- From: "Stewart Nelson" To: Sent: 25 February 2004 07:42 Subject: LF: Re: WOLF development > Your keyed oscillator idea is interesting, but it appears to > introduce another unknown. For example, if the 136 kHz oscillator > drifted up 0.01 Hz, it would affect the audio in the same way > as the receiver LO drifting down 0.01 Hz. One way to resolve > this ambiguity would be to digitally divide the 136 kHz into > the audio range, and feed that into the sound card, too. > Do you have a simpler solution? > I suspect you have "forgotten" the properties of a keyed oscillator in this application. If the 136khz oscillator is stopped and re-started by the 1pps signal it will lock and not drift. I agree that if just the oscillator output is keyed (so the whole comb drifts as well) then the osc drift will be a variable, but the keyed oscillator becomes a locked comb-generator. (Tube technology revisited !!) Thus it should be possible to construct this as an LC oscillator. I have not done the maths but I suspect that the smallscale sawtooth FSK created by the drift during the interval between locking pulses will "spread" the line a little, but averaging should be able to remove this satisfactorily. My LF RXs (AOR 7030 s ) whilst stable (TCXO), have no facility to feed in an external standard. The TCXO is a "funny frequency" too. Fascinating stuff. Cheers de Alan G3NYK alan.melia@btinternet.com