Return-Path: <owner-rsgb_lf_group@blacksheep.org> Received: (qmail 15897 invoked from network); 1 Sep 2003 13:03:00 -0000 Received: from murphys.services.quay.plus.net (212.159.14.225) by netmail00.services.quay.plus.net with SMTP; 1 Sep 2003 13:03:00 -0000 Received: (qmail 20724 invoked from network); 1 Sep 2003 13:02:45 -0000 X-Filtered-by: Plusnet (hmail v1.01) X-MSMail-Priority: High X-Spam-detection-level: 11 Received: from post.thorcom.com (193.82.116.70) by murphys.services.quay.plus.net with SMTP; 1 Sep 2003 13:02:25 -0000 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 X-Fake-Domain: majordom Received: from majordom by post.thorcom.com with local (Exim 4.14) id 19toJG-0007LI-IO for rsgb_lf_group-outgoing@blacksheep.org; Mon, 01 Sep 2003 14:01:30 +0100 Received: from [212.1.130.141] (helo=smtp-1.visp.telinco.net) by post.thorcom.com with esmtp (Exim 4.14) id 19toJC-0007L4-Fk for rsgb_lf_group@blacksheep.org; Mon, 01 Sep 2003 14:01:26 +0100 Received: from [80.40.88.180] (helo=standalone) by smtp-1.visp.telinco.net with smtp (Exim 3.36 #1) id 19toJB-0003Ar-00 for rsgb_lf_group@blacksheep.org; Mon, 01 Sep 2003 14:01:26 +0100 Received: by localhost with Microsoft MAPI; Mon, 1 Sep 2003 13:59:43 +0100 Message-ID: <01C37091.4B597AB0.g4jnt@thersgb.net> From: "Andy talbot" <g4jnt@thersgb.net> To: rsgb_lf_group@blacksheep.org Date: Mon, 1 Sep 2003 13:59:08 +0100 Importance: high X-Priority: 1 X-Mailer: Microsoft Internet E-mail/MAPI - 8.0.0.4211 MIME-Version: 1.0 Subject: RE: LF: Re: GPS-locked PSK tests Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 8bit X-Spam-Status: No, hits=1.9 required=5.0tests=X_PRIORITY_HIGHversion=2.55 X-Spam-Level: * X-Spam-Checker-Version: SpamAssassin 2.55 (1.174.2.19-2003-05-19-exp) 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: rsgb_lf_group-outgoing@blacksheep.org X-SA-Exim-Scanned: No; SAEximRunCond expanded to false X-Spam-Rating: 1 At the moment that is basically all that I'm using. An analogue vectorscope made by multiplying two quadrature 1kHz waveforms by the output fom the Rx after passing though a 1kHz bandpass filter. The outputs from each multiplier are then passed through a pair of identical 10Hz low pass filters. Everything up to this point is done with op amps and simple CMOS. At this stage the outputs could be viewed on a 'scope in X-Y mode, but I choose to digitise them and process with further integration on a PC. This allows the exact phase to be calculated rather than estimated from a scope trace. There is nothing to stop the low pass filters being made much narrower and sticking with a simple scope to view the signal. I can send a copy of the circuit of the analogue part of the electronics to anyone interested. It also includes a simple LED based phase display driven from the 1kHz bandpass filter output, so a strongish signal can be seen to rotate around a circle of 8 LEDS. The next stage is to do the 1kHz quadrature multiplication and avergaing in a PIC, but as the system works Ok as it is, that is a low priority job. Andy G4JNT . >I think a DSP scheme like G4JNT is using is the best way of doing these >phase measurements in the long run, but in the mean time, I intend to >resurrect the "vectorscope" circuit I built a while back - this should also >be able to remove the PSK modulation from the R4 and DLF carriers, with >suitable choice of time constant. >s