Return-Path: <owner-rsgb_lf_group@blacksheep.org> Received: (qmail 54955 invoked from network); 1 Dec 2004 18:23:48 -0000 Received: from unknown (HELO ptb-spamcore02.plus.net) (192.168.71.3) by ptb-mailstore01.plus.net with SMTP; 1 Dec 2004 18:23:48 -0000 Received: from mailnull by ptb-spamcore02.plus.net with spamcore-l-b (Exim 4.32; FreeBSD) id 1CZZAE-000O7r-PH for dave@picks.force9.co.uk; Wed, 01 Dec 2004 18:25:19 +0000 Received: from [192.168.67.1] (helo=ptb-mxcore01.plus.net) by ptb-spamcore02.plus.net with esmtp (Exim 4.32; FreeBSD) id 1CZZAE-000O7o-Mq for dave@picks.force9.co.uk; Wed, 01 Dec 2004 18:25:18 +0000 Received: from post.thorcom.com ([193.82.116.20]) by ptb-mxcore01.plus.net with esmtp (Exim 4.30; FreeBSD) id 1CZZ8l-000E1O-8V for dave@picks.force9.co.uk; Wed, 01 Dec 2004 18:23:47 +0000 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1CZZ85-0002sT-6J for rs_out_1@blacksheep.org; Wed, 01 Dec 2004 18:23:05 +0000 Received: from [193.82.116.30] (helo=relay.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1CZZ84-0002sK-Py for rsgb_lf_group@blacksheep.org; Wed, 01 Dec 2004 18:23:04 +0000 Received: from mout1.freenet.de ([194.97.50.132]) by relay.thorcom.net with esmtp (Exim 4.41) id 1CZZ80-0000kZ-RH for rsgb_lf_group@blacksheep.org; Wed, 01 Dec 2004 18:23:04 +0000 Received: from [194.97.50.136] (helo=mx3.freenet.de) by mout1.freenet.de with esmtpa (Exim 4.43) id 1CZZ7f-0004O3-Qe for rsgb_lf_group@blacksheep.org; Wed, 01 Dec 2004 19:22:39 +0100 Received: from pd9503e4a.dip.t-dialin.net ([217.80.62.74] helo=[192.168.0.200]) by mx3.freenet.de with esmtpsa (ID dl4yhf@freenet.de) (TLSv1:AES256-SHA:256) (Exim 4.43 #13) id 1CZZ7f-0006h8-HZ for rsgb_lf_group@blacksheep.org; Wed, 01 Dec 2004 19:22:39 +0100 Message-ID: <41AE0BF6.2050408@freenet.de> Date: Wed, 01 Dec 2004 19:22:46 +0100 From: Wolf DL4YHF <dl4yhf@freenet.de> User-Agent: Mozilla Thunderbird 0.9 (Windows/20041103) X-Accept-Language: de-DE, de, en-us, en MIME-Version: 1.0 To: RSGB LF Group <rsgb_lf_group@blacksheep.org> X-SPF-Result: relay.thorcom.net: 194.97.50.132 is neither permitted nor denied by domain of freenet.de X-Spam-Score: 0.2 (/) X-Spam-Report: autolearn=no,RCVD_IN_NJABL=0.1,RCVD_IN_SORBS=0.1 Subject: Re: LF: Variable-PSK theory (warning - goes on a bit!) 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) Hello Jim and group, Thanks for the "Variable PSK" thoughts - will take some more time to thing about them again. We (that's Markus DF6NM and myself) came to similar conclusions that ... - with an optimum-shaped "slow" phase transition you end up at MSK - if one doesn't attempt to write the "ultimate (matched) decoder" for MSK, it isn't sooo tough (but..) - some clever ideas for synchronisation at very low symbol rates must be implemented (one of them being simply to synchronize it "manually" looking at a radio-controlled clock). As I see it, a fully automated digital mode which does "everything" itself is not favourable compared to CW (oh but please don't let us start debates on this again), and even QRSS / DFCW and other "visual" modes have their charm - the operator's brain wants to be involved in the decoding process.. but that's just a personal opinion. As Brian wrote.. > So, in the absence of a narrow-band medium-speed keyboard mode that can be transmitted through a non-linear amplifier, is it time to review how we make best use of our 2.1 kHz ?? < Help may(!) be on the way, most likely a slow variant of G3PLX's PSK31 in QPSK mode (which is already possible to send and decode), turned into MSK "somehow" to remove the need for a linear transmitter. This may be achieved by delaying the signal in the quadrature phase branch (of the modulator and demodulator) for a half symbol time, and shaping the pulses before the modulator. This way there will be no more 180° phase transitions in the modulated audio signal, only 90° phase changes, and the amplitude will be constant by means of the data pulse shaping. I have no idea if, when, and how this will be implemented yet, it all depends... Greetings, Wolf DL4YHF .