Return-Path: <majordom@post.thorcom.com> Received: (qmail 7808 invoked from network); 2 Apr 2001 16:57:49 -0000 Received: from unknown (HELO murphys-inbound.servers.plus.net) (212.159.14.225) by excalibur.plus.net with SMTP; 2 Apr 2001 16:57:49 -0000 Received: (qmail 11394 invoked from network); 2 Apr 2001 16:57:44 -0000 Received: from unknown (HELO post.thorcom.com) (212.172.148.70) by murphys with SMTP; 2 Apr 2001 16:57:44 -0000 X-Priority: 3 X-MSMail-Priority: Normal Received: from majordom by post.thorcom.com with local (Exim 3.16 #2) id 14k7Wy-0000rI-00 for rsgb_lf_group-outgoing@blacksheep.org; Mon, 02 Apr 2001 17:50:16 +0100 Received: from hestia.herts.ac.uk ([147.197.200.9]) by post.thorcom.com with esmtp (Exim 3.16 #2) id 14k7Ws-0000p8-00 for rsgb_lf_group@blacksheep.org; Mon, 02 Apr 2001 17:50:10 +0100 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Received: from [147.197.200.44] (helo=gemini) by hestia.herts.ac.uk with esmtp (Exim 3.16 #4) id 14k7WU-00045k-00 for rsgb_lf_group@blacksheep.org; Mon, 02 Apr 2001 17:49:46 +0100 Message-ID: <24716.200104021649@gemini> From: "James Moritz" <j.r.moritz@herts.ac.uk> Organization: University of Hertfordshire To: rsgb_lf_group@blacksheep.org Date: Mon, 2 Apr 2001 17:54:48 +0000 MIME-Version: 1.0 Content-Type: text/enriched; charset=US-ASCII Content-Transfer-Encoding: 8bit Subject: LF: <Tech> Re: PSK Tx solution? X-Mailer: Pegasus Mail for Win32 (v3.11) Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group Sender: <majordom@post.thorcom.com> <?color><?param 0100,0100,0100>Dear Mike, LF group,<br><br>G3XDV wrote:<br>><?/color>My understanding is that for voice transmissions NBFM and >phase mod are differently achieved but result in roughly the same >mathematics so can be demodulated as if they were identical. <br>>In the same way, can we achieve the same effect as PSK by >doing something with the frequency instead? If so, linearity is not >an issue.<br><br>That's exactly what my prototype circuit is aiming to do. So far, it demonstrates that BPSK-like signals with constant amplitude (and therefore not requiring a linear amp) can be generated with acceptable sidebands using a phase modulator. These signals could be viewed mathematically as either phase- or frequency modulation. However, to obtain the benefits of coherent signal detection, it is neccesary to preserve a definite fixed relationship between the phase of the modulated signal, and a reference phase (the carrier). Practical p hase modulators do this, but practical analogue frequency modulators (basically voltage controlled oscillators) don't.<br><br>So far so good, but now the question is are these phase-modulated signals compatible with BPSK as far as reception is concerned? That's the next stage in the experiment....<br><br>Cheers, Jim Moritz<br>73 de M0BMU<br><br><br>