Return-Path: Received: from mtain-dc06.r1000.mx.aol.com (mtain-dc06.r1000.mx.aol.com [172.29.64.134]) by air-mb05.mail.aol.com (v129.10) with ESMTP id MAILINMB054-a5bc4daf62c0134; Wed, 20 Apr 2011 18:48:32 -0400 Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-dc06.r1000.mx.aol.com (Internet Inbound) with ESMTP id 2F81C380000CD; Wed, 20 Apr 2011 18:48:30 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1QCgAn-0007Ac-Ts for rs_out_1@blacksheep.org; Wed, 20 Apr 2011 23:47:01 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1QCgAm-0007AT-Vr for rsgb_lf_group@blacksheep.org; Wed, 20 Apr 2011 23:47:00 +0100 Received: from qmta06.westchester.pa.mail.comcast.net ([76.96.62.56]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1QCgAk-0003bp-Eh for rsgb_lf_group@blacksheep.org; Wed, 20 Apr 2011 23:47:00 +0100 Received: from omta23.westchester.pa.mail.comcast.net ([76.96.62.74]) by qmta06.westchester.pa.mail.comcast.net with comcast id ZyZD1g0091c6gX856ymslW; Wed, 20 Apr 2011 22:46:52 +0000 Received: from JAYDELL ([76.23.233.102]) by omta23.westchester.pa.mail.comcast.net with comcast id Zymr1g00E2DDHkk3jymr61; Wed, 20 Apr 2011 22:46:51 +0000 Message-ID: <001401cbffac$db482fb0$8d01a8c0@JAYDELL> From: To: References: <4DAF42C1.8010401@telus.net> ,<3F558BACA835487AA4B9600B9AF13DD9@AGB> Date: Wed, 20 Apr 2011 18:46:58 -0400 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.2180 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2180 X-Spam-Score: 0.8 (/) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001,MAILTO_TO_SPAM_ADDR=0.276,NO_REAL_NAME=0.55 Subject: Re: LF: MSK with a Class D transmitter...? Content-Type: multipart/alternative; boundary="----=_NextPart_000_0010_01CBFF8B.53E58980" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: ** X-Spam-Status: No, hits=2.1 required=5.0 tests=HTML_30_40,HTML_MESSAGE, MAILTO_TO_SPAM_ADDR,NO_REAL_NAME 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: 3039ac1d40864daf62be4750 X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none ------=_NextPart_000_0010_01CBFF8B.53E58980 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Laurence ... and other interested parties Just updated the web page with the improved doubler circuit that I've been using this season. I should have updated this a while ago. While the original circuit worked well on 500 kHz the duty cycle at 137 kHz was far enough off to be of concern. The new circuit is slightly more involved and band specific but the parts are a bit more 'garden variety'. Here's the new circuit: http://www.w1vd.com/X2LinearClassDinterface.html Jay W1VD WD2XNS WE2XGR/2 ----- Original Message ----- From: Laurence KL7UK To: rsgb_lf_group@blacksheep.org Sent: Wednesday, April 20, 2011 5:25 PM Subject: RE: LF: MSK with a Class D transmitter...? http://www.w1vd.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 transmitter...? Its the shift that's the problem , going for a x2 audio may drop you out side the ssb filter pass band ..... From: Andy Talbot Sent: Wednesday, April 20, 2011 10:09 PM To: rsgb_lf_group@blacksheep.org 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 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 two 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. Alternatively, 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 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 correctly due to the fact MSK does not have amplitude component 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 ------=_NextPart_000_0010_01CBFF8B.53E58980 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Laurence ... and other interested parties
 
Just updated the web page with the improv= ed doubler=20 circuit that I've been using this season. I should have updated this= a while=20 ago. While the original circuit worked well= on 500=20 kHz the duty cycle at 137 kHz was far enough off to be of concern= . The new=20 circuit is slightly more involved and band specific but the parts are= a bit more=20 'garden variety'.
 
Here's the new circuit:
 
 
Jay W1VD  WD2XNS  WE2XGR/2
----- Original Message -----
From:=20 Laurence KL7UK
Sent: Wednesday, April 20, 20= 11 5:25=20 PM
Subject: RE: LF: MSK with a= Class D=20 transmitter...?

http://www.w1vd.com/X2LinearClassDinterface.html = =20 or.....
 
Laurence G4DMA
 
From: g8fzk@g8fzk.fsn= et.co.uk
To: rsgb_lf_group@blacksheep.org
Date:=20 Wed, 20 Apr 2011 22:18:36 +0100
Subject: Re: LF: MSK with a Class= D=20 transmitter...?

Its the  shift that's  th= e =20 problem  , going  for a  x2  audio  may&nbs= p;=20 drop  you  out  side the  ssb  filter = =20 pass  band .....

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

Bin too quick to type..
NOt thinking straight...
 
You need to the upconvert either the resulting doubled audio to= ne by=20 twice the RF carrier, or upconvert first and double the final RF.&nb= sp; Same=20 ideas for frequency doubling can be used.
 
See http://www.g4jnt.com/LFUpconv.pdf  for a direct from= =20 audio upconverter.
 
Must fully check before hitting SEND !
 
Andy
G4JNT

On 20 April 2011 21:50, Andy Talbot <andy.g= 4jnt@gmail.com>=20 wrote:
I assume you are genrating the MSK from soundcard output= , in which=20 case two options come to mind:
 
1)  Double the frequency.  Full wave rectify the au= dio=20 sinusoid, pass the AC part of the result into a comparator and int= o the=20 divider.  Alternatively, as the signal bandwidth is prob= ably quite=20 low, square up the audio to start with, feed into one inpiut of an= XOR=20 gate.  Delay the waveform by 90 deg and feed this into the ot= he side of=20 the XOR.    Output of XOR to divider as before
 
2)   Remove the  divide by two, and replace wi= th an=20 inverter / buffer pair to generate the out of phase drive=20 signals.   The  input now needs to be close to= a 1:1=20 squarwave at output frequency.   Pass the soundcard audi= o into a=20 comparator and make sure it gives a 50% duty cycles.
 
 
Andy
 
ps.=20
or 3)    Convince the software author the S/W= needs=20 modifying to give a 2.F output
 
 
On 20 April 2011 21:32, Scott Tilley= <sthed475@telus.net>=20 wrote:
Hi All

I=20 wonder if someone can explain to me how to feed an MSK signal in= to a=20 typical Class D transmitter?

I mean by typical that the= TX has a=20 4013 type /2 system feeding two FET drivers to drive FETs in a= push-pull=20 configuration.

If I understand correctly due to the fact= MSK does=20 not have amplitude component to its signal that a non-linear tra= nsmitter=20 can be used.

So, how do you do this with a Class-D TX as= often used=20 in=20 LF/VLF?

Thanks,
Scott
VE7TIL







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