Return-Path: Received: from mtain-mg01.r1000.mx.aol.com (mtain-mg01.r1000.mx.aol.com [172.29.96.201]) by air-md06.mail.aol.com (v129.10) with ESMTP id MAILINMD061-8b884db06df6282; Thu, 21 Apr 2011 13:48:38 -0400 Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-mg01.r1000.mx.aol.com (Internet Inbound) with ESMTP id BD3A2380000BB; Thu, 21 Apr 2011 13:48:36 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1QCxyh-0000jZ-2O for rs_out_1@blacksheep.org; Thu, 21 Apr 2011 18:47:43 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1QCxyg-0000jQ-E5 for rsgb_lf_group@blacksheep.org; Thu, 21 Apr 2011 18:47:42 +0100 Received: from cavuit02.kulnet.kuleuven.be ([134.58.240.44]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1QCxye-0006KX-1C for rsgb_lf_group@blacksheep.org; Thu, 21 Apr 2011 18:47:42 +0100 Received: from smtps01.kuleuven.be (smtpshost01.kulnet.kuleuven.be [134.58.240.74]) by cavuit02.kulnet.kuleuven.be (Postfix) with ESMTP id B4E4451C698 for ; Thu, 21 Apr 2011 19:47:30 +0200 (CEST) Received: from ICTS-S-HUB-N2.luna.kuleuven.be (icts-s-hub-n2.luna.kuleuven.be [10.112.9.12]) by smtps01.kuleuven.be (Postfix) with ESMTP id 952DE31E702 for ; Thu, 21 Apr 2011 19:47:30 +0200 (CEST) Received: from ICTS-S-EXC2-CA.luna.kuleuven.be ([10.112.11.13]) by ICTS-S-HUB-N2.luna.kuleuven.be ([10.112.9.12]) with mapi; Thu, 21 Apr 2011 19:47:30 +0200 X-Kuleuven: This mail passed the K.U.Leuven mailcluster From: Rik Strobbe To: "rsgb_lf_group@blacksheep.org" Date: Thu, 21 Apr 2011 19:46:29 +0200 Thread-Topic: LF: MSK with a Class D transmitter...? Thread-Index: AcwASau8jlpGfJi4SsengxaPc1y1LAAAl/Vk Message-ID: References: <4DAF42C1.8010401@telus.net> <4DAF7A16.4040208@telus.net>, In-Reply-To: Accept-Language: nl-NL, nl-BE Content-Language: nl-BE X-MS-Has-Attach: X-MS-TNEF-Correlator: acceptlanguage: nl-NL, nl-BE MIME-Version: 1.0 X-KULeuven-Information: Katholieke Universiteit Leuven X-KULeuven-Scanned: Found to be clean X-KULeuven-Envelope-From: rik.strobbe@fys.kuleuven.be X-Spam-Score: 0.3 (/) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001,MAILTO_TO_SPAM_ADDR=0.276 Subject: RE: LF: MSK with a Class D transmitter...? Content-Type: multipart/alternative; boundary="_000_BF4A524700075746A6467658DFC7102C88B4A788BDICTSSEXC2CAlu_" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: * X-Spam-Status: No, hits=1.6 required=5.0 tests=HTML_20_30, HTML_FONTCOLOR_UNSAFE,HTML_MESSAGE,MAILTO_TO_SPAM_ADDR, TO_ADDRESS_EQ_REAL 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: 3039ac1d60c94db06df3770c X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none X-Mailer: Unknown (No Version) --_000_BF4A524700075746A6467658DFC7102C88B4A788BDICTSSEXC2CAlu_ Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Hello Scott, what kind of MSK do you want to transmit ? WSPR by any chance ? 73, Rik ON7YD - OR7T On 21 April 2011 01:28, Scott Tilley > wrote: Hi Andy Holy mind bogglingness batman... Here's the parameters to make this real simple: - I want to generate a MSK signal out of the transmitter at 8970Hz. - I'm using Spectrum Lab, which allows me to create a MSK drive and at a= baud rate I want at any frequency my sound card can generate. - SL allows me to output quadrature outputs. So, If I understand correctly pump said FET driver with the quadrature out= puts from the sound card audio (squaring up the sine waves of course) and= it should work? Thanks, Scott On 4/20/2011 2:09 PM, Andy Talbot wrote: 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 http://www.g4jnt.com/LFUpconv.pdf for a direct from audio upconverter= . Must fully check before hitting SEND ! 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: 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 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. Andy www.g4jnt.com ps. or 3) Convince the software author the S/W needs modifying to give a 2.= F output 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 --_000_BF4A524700075746A6467658DFC7102C88B4A788BDICTSSEXC2CAlu_ Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Hello Scott,

 

what kind of MSK do you want to transm= it ?

WSPR by any chance ?

 

73, Rik  ON7YD - OR7T


 
On 21 April 2011 01:28, Scott Tilley <sthed475@telus.net&= gt; wrote:
Hi Andy

Holy mind bogglingness batman...

Here's the parameters to make this real simple:
- I want to generate a MSK signal out of the transmitter at 8970Hz.
- I'm using Spectrum Lab, which allows me to create a MSK drive and at a= baud rate I want at any frequency my sound card can generate.
- SL allows me to output quadrature outputs.

So, If I understand correctly pump said FET driver with the quadrature out= puts from the sound card audio (squaring up the sine waves of course) and= it should work?

Thanks,
Scott






On 4/20/2011 2:09 PM, Andy Talbot wrote:
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 h= ttp://www.g4jnt.com/LFUpconv.pdf  for a direct from audio upconve= rter.
 
Must fully check before hitting SEND !
 
Andy
G4JNT

On 20 April 2011 21:50, Andy Talbot <andy.g4jnt@gmail.com<= /a>> 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 befor= e
 
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
 
ps.
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&= gt; 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







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