Return-Path: Received: from mtain-ma02.r1000.mx.aol.com (mtain-ma02.r1000.mx.aol.com [172.29.96.10]) by air-db01.mail.aol.com (v129.10) with ESMTP id MAILINDB013-86434daf4f8f13c; Wed, 20 Apr 2011 17:26:39 -0400 Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-ma02.r1000.mx.aol.com (Internet Inbound) with ESMTP id 79EA238000132; Wed, 20 Apr 2011 17:26:36 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1QCeu0-0006zo-2i for rs_out_1@blacksheep.org; Wed, 20 Apr 2011 22:25:36 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1QCetz-0006zf-DY for rsgb_lf_group@blacksheep.org; Wed, 20 Apr 2011 22:25:35 +0100 Received: from blu0-omc1-s2.blu0.hotmail.com ([65.55.116.13]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1QCetx-0002LZ-CL for rsgb_lf_group@blacksheep.org; Wed, 20 Apr 2011 22:25:35 +0100 Received: from BLU153-W13 ([65.55.116.8]) by blu0-omc1-s2.blu0.hotmail.com with Microsoft SMTPSVC(6.0.3790.4675); Wed, 20 Apr 2011 14:25:26 -0700 Message-ID: X-Originating-IP: [138.32.32.166] From: Laurence KL7UK To: Date: Wed, 20 Apr 2011 13:25:26 -0800 Importance: Normal In-Reply-To: <3F558BACA835487AA4B9600B9AF13DD9@AGB> References: <4DAF42C1.8010401@telus.net> ,<3F558BACA835487AA4B9600B9AF13DD9@AGB> MIME-Version: 1.0 X-OriginalArrivalTime: 20 Apr 2011 21:25:26.0856 (UTC) FILETIME=[776BC480:01CBFFA1] X-Spam-Score: 0.3 (/) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001,MAILTO_TO_SPAM_ADDR=0.276 Content-Type: multipart/alternative; boundary="_a647e68d-da5a-4d7c-9874-07800afa2b04_" Subject: RE: LF: MSK with a Class D transmitter...? X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: * X-Spam-Status: No, hits=1.5 required=5.0 tests=FORGED_HOTMAIL_RCVD,HTML_20_30, HTML_MESSAGE,MAILTO_TO_SPAM_ADDR 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-aol-global-disposition: G x-aol-sid: 3039ac1d600a4daf4f8c795c X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none X-Mailer: Unknown (No Version) --_a647e68d-da5a-4d7c-9874-07800afa2b04_ Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable http://www.w1vd.com/X2LinearClassDinterface.html or..... =20 Laurence G4DMA =20 From: g8fzk@g8fzk.fsnet.co.uk To: rsgb_lf_group@blacksheep.org Date: Wed, 20 Apr 2011 22:18:36 +0100 Subject: Re: LF: MSK with a Class D transmitter...? Its the shift that's the problem , going for a x2 audio may drop= you out side the ssb filter pass band .....=20 From: Andy Talbot=20 Sent: Wednesday, April 20, 2011 10:09 PM To: rsgb_lf_group@blacksheep.org=20 Subject: Re: LF: MSK with a Class D transmitter...? Bin too quick to type.. NOt thinking straight... =20 You need to the upconvert either the resulting doubled audio tone by twice= the RF carrier, or upconvert first and double the final RF. Same ideas= for frequency doubling can be used. =20 See http://www.g4jnt.com/LFUpconv.pdf for a direct from audio upconverter= . =20 Must fully check before hitting SEND ! =20 Andy G4JNT On 20 April 2011 21:50, Andy Talbot wrote: I assume you are genrating the MSK from soundcard output, in which case tw= o options come to mind: =20 1) Double the frequency. Full wave rectify the audio sinusoid, pass the= AC part of the result into a comparator and into the divider. Alternativ= ely, as the signal bandwidth is probably quite low, square up the audio to= start with, feed into one inpiut of an XOR gate. Delay the waveform by= 90 deg and feed this into the othe side of the XOR. Output of XOR to= divider as before =20 2) Remove the divide by two, and replace with an inverter / buffer pair= to generate the out of phase drive signals. The input now needs to be= close to a 1:1 squarwave at output frequency. Pass the soundcard audio= into a comparator and make sure it gives a 50% duty cycles. =20 =20 Andy www.g4jnt.com =20 ps.=20 or 3) Convince the software author the S/W needs modifying to give a 2.= F output =20 =20 On 20 April 2011 21:32, Scott Tilley wrote: Hi All I wonder if someone can explain to me how to feed an MSK signal into a typ= ical Class D transmitter? I mean by typical that the TX has a 4013 type /2 system feeding two FET dr= ivers to drive FETs in a push-pull configuration. If I understand correctly due to the fact MSK does not have amplitude comp= onent to its signal that a non-linear transmitter can be used. So, how do you do this with a Class-D TX as often used in LF/VLF? Thanks, Scott VE7TIL =3D --_a647e68d-da5a-4d7c-9874-07800afa2b04_ Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable http://www.w1= vd.com/X2LinearClassDinterface.html  or.....
 
Laurence G4DMA
 
From: g8fzk@g8fzk.fsnet.co.uk
To: rsgb_lf_group@blacksheep.org
Date:= Wed, 20 Apr 2011 22:18:36 +0100
Subject: Re: LF: MSK with a Class D tr= ansmitter...?

Its the  shift that's  the = ; problem  , going  for a  x2  audio  may = drop  you  out  side the  ssb  filter  pass=   band .....

Sent: Wednesday, April 20, 2011 10:09 PM
Subject: Re: LF: MSK with a Class D transmitter...?

Bin too quick to type..
NOt thinking straight...
 
You need to the upconvert either the resulting doubled audio tone by= twice the RF carrier, or upconvert first and double the final RF. = Same ideas for frequency doubling can be used.
 
See htt= p://www.g4jnt.com/LFUpconv.pdf  for a direct from audio upconvert= er.
 
Must fully check before hitting SEND !
 
Andy
G4JNT

On 20 April 2011 21:50, Andy Talbot <andy.g4jnt@gmail.com> wrote:
I assume you are genrating the MSK from soundcard output, in whi= ch case two options come to mind:
 
1)  Double the frequency.  Full wave rectify the audio sinu= soid, pass the AC part of the result into a comparator and into the= divider.  Alternatively, as the signal bandwidth is probably qu= ite low, square up the audio to start with, feed into one inpiut of an XOR= gate.  Delay the waveform by 90 deg and feed this into the othe side= of the XOR.    Output of XOR to divider as before
 
2)   Remove the  divide by two, and replace with an in= verter / buffer pair to generate the out of phase drive signals. &nbs= p; The  input now needs to be close to a 1:1 squarwave at output= frequency.   Pass the soundcard audio into a comparator and mak= e sure it gives a 50% duty cycles.
 
 
Andy
www.g4jnt.com
 
ps.=20
or 3)    Convince the software author the S/W needs mo= difying to give a 2.F output
 
 
On 20 April 2011 21:32, Scott Tilley <sthed475@telus.net>= ; wrote:
Hi All

I wonder if someone can explain to me how= to feed an MSK signal into a typical Class D transmitter?

I mean= by typical that the TX has a 4013 type /2 system feeding two FET drivers= to drive FETs in a push-pull configuration.

If I understand correc= tly due to the fact MSK does not have amplitude component to its signal th= at a non-linear transmitter can be used.

So, how do you do this wit= h a Class-D TX as often used in LF/VLF?

Thanks,
Scott
VE7TIL<= BR>




<= BR>
=3D --_a647e68d-da5a-4d7c-9874-07800afa2b04_--