Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-mc05.r1000.mx.aol.com (Internet Inbound) with ESMTP id E4FA338000082; Sun, 31 Jul 2011 09:56:53 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1QnWUz-0000Oe-7Q for rs_out_1@blacksheep.org; Sun, 31 Jul 2011 14:56:09 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1QnWUy-0000OV-LW for rsgb_lf_group@blacksheep.org; Sun, 31 Jul 2011 14:56:08 +0100 Received: from smtp7.freeserve.com ([80.12.242.2] helo=smtp6.freeserve.com) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1QnWUw-00032o-J0 for rsgb_lf_group@blacksheep.org; Sun, 31 Jul 2011 14:56:08 +0100 Received: from me-wanadoo.net (localhost [127.0.0.1]) by mwinf3j13.me.freeserve.com (SMTP Server) with ESMTP id ADAF43000104 for ; Sun, 31 Jul 2011 15:56:00 +0200 (CEST) Received: from me-wanadoo.net (localhost [127.0.0.1]) by mwinf3j13.me.freeserve.com (SMTP Server) with ESMTP id 9B8493000109 for ; Sun, 31 Jul 2011 15:56:00 +0200 (CEST) Received: from AGB (unknown [2.26.45.190]) by mwinf3j13.me.freeserve.com (SMTP Server) with SMTP id 22D1F3000104 for ; Sun, 31 Jul 2011 15:55:58 +0200 (CEST) X-ME-UUID: 20110731135558142.22D1F3000104@mwinf3j13.me.freeserve.com Message-ID: From: "Graham" To: References: <4E355332.6010107@iup.uni-heidelberg.de> <4E355927.4010905@iup.uni-heidelberg.de> <4E355CF9.8020504@iup.uni-heidelberg.de> In-Reply-To: <4E355CF9.8020504@iup.uni-heidelberg.de> Date: Sun, 31 Jul 2011 14:55:57 +0100 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal Importance: Normal X-Mailer: Microsoft Windows Live Mail 14.0.8117.416 X-MimeOLE: Produced By Microsoft MimeOLE V14.0.8117.416 X-Antivirus: avast! (VPS 110731-0, 31/07/2011), Outbound message X-Antivirus-Status: Clean X-Spam-Score: 0.2 (/) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001,RCVD_ILLEGAL_IP=0.234 Subject: Re: LF: frequency doubler and divider Content-Type: multipart/alternative; boundary="----=_NextPart_000_0031_01CC4F91.F481EEF0" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.6 required=5.0 tests=HTML_20_30,HTML_MESSAGE, MISSING_OUTLOOK_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-SCOLL-SCORE: 0:2:477202784:93952408 X-AOL-SCOLL-URL_COUNT: 0 x-aol-sid: 3039ac1d604d4e355f256516 X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none This is a multi-part message in MIME format. ------=_NextPart_000_0031_01CC4F91.F481EEF0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Has anyone looked closely at Jim's Class D/E EER tx ?=20 From: Stefan Sch=E4fer=20 Sent: Sunday, July 31, 2011 2:47 PM To: rsgb_lf_group@blacksheep.org=20 Subject: Re: LF: frequency doubler and divider Oh dear, sorry for 1000s mails today. I got another idea: If you want a 50% duty cycle at 2x f input, you may = just add another XOR gate and do the same again. Then having 4x f input = at an unaccurate duty cycle and feed that to the 4013. Here we are at = 50% at 2x f input :-) Will that work? With to cheep ICs and 2x R and 2x = C? :-) I'll try! 73, Stefan Am 31.07.2011 15:31, schrieb Stefan Sch=E4fer:=20 Ah, regarding the overlap times: I successfully tried a SG3525 SMPS = driver to obtain a defined dead-time. So i won't need the inverted = signal but a 50% duty cycle anyway. Power losses of the FETs (4x = IRFP460) have been excellent low! 73s Am 31.07.2011 15:16, schrieb Andy Talbot:=20 No, that doesn't work to give a true square wave. If the RC delay = is not exactly 50% you get a repeated double pulse waveform and not a = series of equally spaced 2.F pulses. On dividing this by 2, you end = up with exactly what you had before. Been there - done that.. :-) The only practical way is to double the frequency, filter it to = remove all odd order terms and the half fundamental then square it up = and divide. Andy www.g4jnt.com =20 2011/7/31 Stefan Sch=E4fer LF, VLF, I just re-invented the wheel ;-) Just by thinking i found one = possible way how to double and divide a rectangular signal, to achieve = an accurate 50 % duty cycle :-) One could take a simple XOR gatter like a CD4070 and a RC circuit. = The time constant has to be about the half of the period of the wanted = frequency, e.g. 3.6 us for 137 kHz. The output of the RC circuit = (voltage across C) and the original signal is fed to one single input of = the gatter. Then the output frequency will be 2x f input. All this can be found in the internet as well, of course. But if = you don't know about that possibility you don't know what to seach in = the web too. At least i haven't found that method by searching and it = also wasn't discussed here in the recent time. Furthermore i never saw = it on a PA design by amateurs i found in the web. The output signal of the 4070 is then fed to the well known = frequency divider consisting out of e.g. a CD4013. Then output frequency = will be the same as on the input but the duty cycle will be accurate = 50%! This is one method to (re-) obtain a suitable drive signal for a H = bridge PA or class D PA after passing the driver signal through an = optocoupler or so. I'm sure i will use that method now in several = circuits, like in the new LF PA that still causes some problems, = excactly on that matter! Later i found on the German wiki site: = http://de.wikipedia.org/wiki/XOR-Gatter#Frequenzverdopplung 73, Stefan/DK7FC ------=_NextPart_000_0031_01CC4F91.F481EEF0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Has anyone  looked  = closely =20 at  Jim's  Class  D/E  EER   tx ? =

From: Stefan Sch=E4fer =
Sent: Sunday, July 31, 2011 2:47 PM
Subject: Re: LF: frequency doubler and = divider

Oh dear, sorry for 1000s mails today.

I got = another idea:=20 If you want a 50% duty cycle at 2x f input, you may just add another XOR = gate=20 and do the same again. Then having 4x f input at an unaccurate duty = cycle and=20 feed that to the 4013. Here we are at 50% at 2x f input :-) Will that = work? With=20 to cheep ICs and 2x R and 2x C? :-) I'll try!

73, = Stefan

Am=20 31.07.2011 15:31, schrieb Stefan Sch=E4fer:=20
Ah,=20 regarding the overlap times: I successfully tried a SG3525 SMPS driver = to=20 obtain a defined dead-time. So i won't need the inverted signal but a = 50% duty=20 cycle anyway. Power losses of the FETs (4x IRFP460) have been = excellent=20 low!

73s

Am 31.07.2011 15:16, schrieb Andy Talbot:=20
No, that doesn't work to give a true square wave.   = If the RC=20 delay is not exactly 50% you get a repeated double pulse waveform = and not a=20 series of equally spaced 2.F pulses.    On dividing = this by=20 2, you end up with exactly what you had before.
 
Been there  - done that.. :-)
 
The only practical way is to double the frequency, filter it to = remove=20 all odd order terms and the half fundamental then square it up and=20 divide.
 
Andy


 
2011/7/31 Stefan Sch=E4fer <schaefer@iup.uni-heidelberg.de> LF, VLF,

I just re-invented the wheel ;-) = Just by=20 thinking i found one possible way how to double and divide a = rectangular=20 signal, to achieve an accurate 50 % duty cycle :-)

One = could take a=20 simple XOR gatter like a CD4070 and a RC circuit. The time = constant has to=20 be about the half of the period of the wanted frequency, e.g. 3.6 = us for=20 137 kHz. The output of the RC circuit (voltage across C) and the = original=20 signal is fed to one single input of the gatter. Then the output = frequency=20 will be 2x f input.

All this can be found in the internet = as well,=20 of course. But if you don't know about that possibility you don't = know=20 what to seach in the web too. At least i haven't found that method = by=20 searching and it also wasn't discussed here in the recent time.=20 Furthermore i never saw it on a PA design by amateurs i found in = the=20 web.

The output signal of the 4070 is then fed to the well = known=20 frequency divider consisting out of e.g. a CD4013. Then output = frequency=20 will be the same as on the input but the duty cycle will be = accurate=20 50%!

This is one method to (re-) obtain a suitable drive = signal for=20 a H bridge PA or class D PA after passing the driver signal = through an=20 optocoupler or so. I'm sure i will use that method now in several=20 circuits, like in the new LF PA that still causes some problems, = excactly=20 on that matter!

Later i found on the German wiki site: http://de.wikipedia.org/wiki/XOR-Gatter#Frequenz= verdopplung

73,=20 = Stefan/DK7FC



=
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