Envelope-to: dave@picks.force9.co.uk Delivery-date: Sun, 24 Apr 2005 19:56:08 +0100 Received: from ptb-spamcore01.plus.net ([192.168.71.1]) by ptb-mxcore04.plus.net with esmtp (PlusNet MXCore v1.0) id 1DPmH2-0007Ar-2H for dave@picks.force9.co.uk; Sun, 24 Apr 2005 19:56:08 +0100 Received: from mailnull by ptb-spamcore01.plus.net with spamcore-l-b (Exim 4.32; FreeBSD) id 1DPmIk-000FFG-8p for dave@picks.force9.co.uk; Sun, 24 Apr 2005 19:57:54 +0100 Received: from [192.168.101.76] (helo=pih-mxcore10.plus.net) by ptb-spamcore01.plus.net with esmtp (Exim 4.32; FreeBSD) id 1DPmIk-000FFD-6U for dave@picks.force9.co.uk; Sun, 24 Apr 2005 19:57:54 +0100 Received: from post.thorcom.com ([193.82.116.20]) by pih-mxcore10.plus.net with esmtp (PlusNet MXCore v1.0) id 1DPmF4-0001wt-CO for dave@picks.force9.co.uk; Sun, 24 Apr 2005 19:54:06 +0100 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1DPmEp-0005Pn-LU for rs_out_1@blacksheep.org; Sun, 24 Apr 2005 19:53:51 +0100 Received: from [193.82.116.30] (helo=relay.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1DPmEp-0005Pe-9A for rsgb_lf_group@blacksheep.org; Sun, 24 Apr 2005 19:53:51 +0100 Received: from smtp810.mail.ukl.yahoo.com ([217.12.12.200]) by relay.thorcom.net with smtp (Exim 4.43) id 1DPmEm-0007si-Py for rsgb_lf_group@blacksheep.org; Sun, 24 Apr 2005 19:53:51 +0100 Received: from unknown (HELO w4o8m9) (james.moritz@btopenworld.com@213.122.42.190 with login) by smtp810.mail.ukl.yahoo.com with SMTP; 24 Apr 2005 18:53:42 -0000 Message-ID: <002001c548fe$effaa0c0$be2a7ad5@w4o8m9> From: "James Moritz" To: rsgb_lf_group@blacksheep.org References: <342999402@web.de> Date: Sun, 24 Apr 2005 19:53:42 +0100 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 5.00.2615.200 X-MimeOLE: Produced By Microsoft MimeOLE V5.00.2615.200 X-SPF-Result: relay.thorcom.net: 217.12.12.200 is neither permitted nor denied by domain of btopenworld.com X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=failed,none Subject: LF: Re: Divider by 10 or 100 for 136k out 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: 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-Spam-Filtered: by PlusNet SpamCORE (v3.00) ----- Original Message ----- From: Hans-Albrecht Haffa To: Sent: Sunday, April 24, 2005 10:28 AM Subject: LF: Divider by 10 or 100 for 136k out > HEF4017 to divide by 5 and > 4013 to divide by 2 ? > Waiting for Your suggtestions, > Hans-Albrecht > DK 8 ND > __________________________________________________________ Dear Hans-Albrecht, LF Group This is one possibility for divide-by-10. The easiest way to get an exact 50% duty cycle is to make the final stage of the divider a "toggle" connected flip-flop to divide by 2. A circuit which does this is shown as part of the G3YXM portable TX (page 61 of "LF today"). The 4000-series ICs are convenient if you are running everything from a 12V supply, but if you want divide-by-100 from 13.6MHz they are marginal - the guaranteed clock frequency for a 4017 is only 5.5MHz with 15V supply, and the 4013 is 12MHz. A better choice for divide-by-100 is the 74HC390, which contains 2 divide-by-5, and 2 divide-by-2 circuits, so will do the job with a single IC ( http://www.semiconductors.philips.com/pip/74HC390N.html ). Note this requires a supply around 5V, and a 0V/+5V logic level input, but it will work up to 60MHz or so. Make sure that, as before, you make the last divider stage one of the divide-by-2 counters; the divide-by-5 does not give a symmetrical output. If you require complementary phase outputs, it would be best to use an external flip-flop as the final divide by 2 stage. Cheers, Jim Moritz 73 de M0BMU