Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on lipkowski.org X-Spam-Level: X-Spam-Status: No, score=-2.3 required=5.0 tests=FREEMAIL_FORGED_FROMDOMAIN, FREEMAIL_FROM,HEADER_FROM_DIFFERENT_DOMAINS,HTML_MESSAGE,RCVD_IN_DNSWL_MED, SPF_PASS,T_DKIM_INVALID autolearn=ham autolearn_force=no version=3.4.0 X-Spam-DCC: EATSERVER: mailn 1166; Body=2 Fuz1=2 Fuz2=2 Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mailn.lipkowski.org (8.14.4/8.14.4/Debian-8+deb8u1) with ESMTP id uBIFnlwU011820 for ; Sun, 18 Dec 2016 16:49:48 +0100 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1cIdfF-00041o-FE for rs_out_1@blacksheep.org; Sun, 18 Dec 2016 15:46:17 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1cIdf9-00041f-Bn for rsgb_lf_group@blacksheep.org; Sun, 18 Dec 2016 15:46:11 +0000 Received: from omr-m016e.mx.aol.com ([204.29.186.16]) by relay1.thorcom.net with esmtps (TLSv1:DHE-RSA-AES256-SHA:256) (Exim 4.87) (envelope-from ) id 1cIdf5-0005Oo-68 for rsgb_lf_group@blacksheep.org; Sun, 18 Dec 2016 15:46:10 +0000 Received: from mtaomg-mcb02.mx.aol.com (unknown [172.26.50.176]) by omr-m016e.mx.aol.com (Outbound Mail Relay) with ESMTP id 6D2CF3800086 for ; Sun, 18 Dec 2016 10:46:05 -0500 (EST) Received: from core-acx02h.mail.aol.com (unknown [10.76.5.147]) by mtaomg-mcb02.mx.aol.com (OMAG/Core Interface) with ESMTP id 1361938000082; Sun, 18 Dec 2016 10:46:04 -0500 (EST) Received: from 188.192.95.60 by webprd-a30.mail.aol.com (10.72.52.207) with HTTP (WebMailUI); Sun, 18 Dec 2016 10:46:03 -0500 Date: Sun, 18 Dec 2016 10:46:03 -0500 From: Markus Vester To: markusvester@aol.com, rsgb_lf_group@blacksheep.org Message-Id: <159129c81a8-3e3c-a9e0@webprd-a30.mail.aol.com> In-Reply-To: <158b02a87b2-1f7f-112fd@webprd-m75.mail.aol.com> MIME-Version: 1.0 X-MB-Message-Source: WebUI X-MB-Message-Type: User X-Mailer: JAS STD X-Originating-IP: [188.192.95.60] x-aol-global-disposition: G DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=mx.aol.com; s=20150623; t=1482075965; bh=CtqHT53uIL7+tZ7bRrC4PfFjIqyfShUwcxd4sOe8nvM=; h=From:To:Subject:Message-Id:Date:MIME-Version:Content-Type; b=kv3Z3gTKykvAe7sEJcxa+A4f7f6fSwjFWIDPAZIF9EtxnDd5VL5JxZxf5j/uCuFLR n8LRWD11YP9fpFoR9LXlxcyx3WVy7iUMjM9RBMeU3Aa+lok1jF4qXFamDWirq32vJn /dvp07/D422XV0WO2KsI0pQvpPPtKRv5UWkwDGGw= x-aol-sid: 3039ac1a32b05856af3c27ae X-Scan-Signature: 4998b3eda037fec4e885bebc9a2db934 Subject: Re: VLF: SpecLab GPS-phaselock with faster PSK Content-Type: multipart/alternative; boundary="----=_Part_55109_765188653.1482075963812" 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-Scanned-By: MIMEDefang 2.75 Status: RO X-Status: X-Keywords: X-UID: 9837 ------=_Part_55109_765188653.1482075963812 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable In the meantime, I have changed the PLL setup again. Now it can only do har= d-keying, but this works down to 1s symbols which is the shortest selectabl= e periodic actions interval. I have swapped the functions of the L and R ch= annel: The auxiliary carrier is now generated by the AM modulator in the R1= -R2 Blackbox, converted to the final frequency in R3, and PSK-modulated in = R4-R5 (bb[3].delayline.bypass_factor). The PSK is undone again in the feedb= ack path in the L1-L2 blackbox, so that the phase comparator sees a constan= t colour and does not have to react to the modulation. There is a small del= ay to compensate for DAC and ADC latencies (500 ms, "timer.expired" in cond= itional actions). One possible pitfall is that the AM modulator carrier level needs to be set= to 0.00002, due to a bug in the scaling from +-32768 to +-1. The entry fie= ld does not have enough digits to show this small number, but the full prec= ision is used and saved in the ini. Best to check the level using one of th= e little scopes at R2 or R3. Here I am using SpecLab v2.92b01 which seems to work fine. The interpreter = commands for the delaylines were introduced sometime around December 2015 s= o older versions won't work.=20 Like before, the frequency is still defined by the middle one of the three = testsignal generators, no other changes are necessary. Don't worry about th= e USB mixer block, it can downconvert as well (e.g. from 2000 to 1495 Hz fo= r an SSB transmitter). I've also changed the format of "pskln.txt" to one line per symbol ("Save R= ows" in ebnaut-tx). For my own transmissions, I've added a final line to se= t a=3D0.5 which turns the carrier off. http://df6nm.bplaced.net/VLF/fec_tests/vlf_tx_pll_fasterpsk.zip (14 kB) Best 73, Markus (DF6NM) -----Urspr=C3=BCngliche Mitteilung-----=20 Von: Markus Vester An: rsgb_lf_group Verschickt: Di, 29 Nov 2016 1:58 pm Betreff: VLF: SpecLab GPS-phaselock with faster PSK The SpecLab GPS-PLL script can overcome soundcard glitches and provide abso= lute phase of the antenna voltage, but PSK modulation has been limited to s= low symbol rates due to the ~ 3 second time constant of the phase swing. It= appears that the PLL latency is mainly due to the digimode terminal genera= ting the output signal, which responds to frequency commands from the inter= preter script only with some delay. I have now tried to circumvent the lag = by using the L3 frequency mixer which can be controlled faster, allowing ph= ase-switching in less than 200 ms.=20 A couple of tricks were necessary: A constant 2 kHz signal is generated in = the L1-L2 blackbox, which is then converted to the desired VLF output frequ= ency. In addition, instantaneous phase switching is implemented by switchin= g the bypass factor in the L4-L5 delay line. Alternatively, the phase can b= e smoothly ramped by setting a "hardkey" flag to zero. =20 The configuration file is here: http://df6nm.bplaced.net/VLF/fec_tests/vlf_tx_pll_fastpsk.zip For EbNaut transmissions, you will need to use Paul's software and prepare = a file "psk.txt" (containing zeroes, ones and spaces, similar to the provid= ed template), and set up start times etc. in scheduled actions. You can als= o produce a simple 2-second test pattern by activating the second line in p= eriodic actions. As before, the output frequency is defined by the second t= est signal generator, which provides the GPS-controlled reference. Hope this may be useful, Markus (DF6NM) =20 ... ------=_Part_55109_765188653.1482075963812 Content-Type: text/html; charset=utf-8 Content-Transfer-Encoding: quoted-printable
In the meantime, I have changed the PLL setup again. Now= it can only do hard-keying, but this works down to 1s symbols which is the= shortest selectable periodic actions interval. I have swapped the function= s of the L and R channel: The auxiliary carrier is now generated by the AM = modulator in the R1-R2 Blackbox, converted to the final frequency in R3, an= d PSK-modulated in R4-R5 (bb[3].delayline.bypass_factor). The PSK is undone= again in the feedback path in the L1-L2 blackbox, so that the phase compar= ator sees a constant colour and does not have to react to the modulation. T= here is a small delay to compensate for DAC and ADC latencies (500 ms, "tim= er.expired" in conditional actions).
One possible pitf= all is that the AM modulator carrier level needs to be set to 0.00002, due = to a bug in the scaling from +-32768 to +-1. The entry field does not have = enough digits to show this small number, but the full precision is used and= saved in the ini. Best to check the level using one of the little scopes a= t R2 or R3.

Here I am using SpecLab v2.92b01 which see= ms to work fine. The interpreter commands for the delaylines were introduce= d sometime around December 2015 so older versions won't work.

Like before, the frequency is still defined by the middle one of t= he three testsignal generators, no other changes are necessary. Don't worry= about the USB mixer block, it can downconvert as well (e.g. from 2000 to 1= 495 Hz for an SSB transmitter).

I've also changed the = format of "pskln.txt" to one line per symbol ("Save Rows" in ebnaut-tx). Fo= r my own transmissions, I've added a final line to set a=3D0.5 which turns = the carrier off.

http://df6nm.bplaced.net/VLF/fec_tests/vlf_tx_pll_f= asterpsk.zip (14 kB)

Best 73,
Markus (DF6NM)


-----Ursp= r=C3=BCngliche Mitteilung-----
Von: Markus Vester <markusvester@aol.= com>
An: rsgb_lf_group <rsgb_lf_group@blacksheep.org>
Versch= ickt: Di, 29 Nov 2016 1:58 pm
Betreff: VLF: SpecLab GPS-phaselock with f= aster PSK

The SpecLab GPS-PLL = script can overcome soundcard glitches and provide absolute phase of the an= tenna voltage, but PSK modulation has been limited to slow symbol rates due= to the ~ 3 second time constant of the phase swing. It appears that the PL= L latency is mainly due to the digimode terminal generating the output sign= al, which responds to frequency commands from the interpreter script only w= ith some delay. I have now tried to circumvent the lag by using the L3 freq= uency mixer which can be controlled faster, allowing phase-switching in les= s than 200 ms.
A couple of tricks were necessary: A c= onstant 2 kHz signal is generated in the L1-L2 blackbox, which is then conv= erted to the desired VLF output frequency. In addition, instantaneous phase= switching is implemented by switching the bypass factor in the L4-L5 delay= line. Alternatively, the phase can be smoothly ramped by setting a "hardke= y" flag to zero.  

For EbNaut transmissions, you= will need to use Paul's software and prepare a file "psk.txt" (containing = zeroes, ones and spaces, similar to the provided template), and set up star= t times etc. in scheduled actions. You can also produce a simple 2-second t= est pattern by activating the second line in periodic actions. As before, t= he output frequency is defined by the second test signal generator, which p= rovides the GPS-controlled reference.

Hope this may be= useful,
Markus (DF6NM) 
...
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