Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-ma02.r1000.mx.aol.com (Internet Inbound) with ESMTP id 742F33800008F; Tue, 2 Aug 2011 13:07:24 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1QoIPw-0005w3-LJ for rs_out_1@blacksheep.org; Tue, 02 Aug 2011 18:06:08 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1QoIPv-0005vu-He for rsgb_lf_group@blacksheep.org; Tue, 02 Aug 2011 18:06:07 +0100 Received: from smtp06.online.nl ([194.134.42.51]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1QoIPt-0003oS-Dq for rsgb_lf_group@blacksheep.org; Tue, 02 Aug 2011 18:06:07 +0100 Received: from smtp06.online.nl (localhost [127.0.0.1]) by smtp06.online.nl (Postfix) with ESMTP id 6622096218 for ; Tue, 2 Aug 2011 19:06:01 +0200 (CEST) Received: from pa3fnytrqxpddu (s529d275f.adsl.wanadoo.nl [82.157.39.95]) by smtp06.online.nl (Postfix) with SMTP for ; Tue, 2 Aug 2011 19:06:01 +0200 (CEST) From: To: Date: Tue, 2 Aug 2011 19:06:01 +0200 Message-ID: MIME-Version: 1.0 X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook IMO, Build 9.0.2416 (9.0.2911.0) In-Reply-To: Importance: Normal X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.5994 X-Online-Scanned: by Cloudmark authority (on smtp06.online.nl) 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: RE: frequency doubler and divider Content-Type: multipart/alternative; boundary="----=_NextPart_000_0004_01CC5147.3816FBE0" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: ** X-Spam-Status: No, hits=2.3 required=5.0 tests=FROM_ENDS_IN_NUMS, HTML_FONTCOLOR_BLUE,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-SCOLL-SCORE: 0:2:448284480:93952408 X-AOL-SCOLL-URL_COUNT: 0 x-aol-sid: 3039ac1d600a4e382ecc45a0 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_0004_01CC5147.3816FBE0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable OK Andy, it was just an old idea,never tried it out.for lf I am using an old fasio= ned class c tube PA,500W from 100 to 700KHz without switching. 73 Victor -----Oorspronkelijk bericht----- Van: owner-rsgb_lf_group@blacksheep.org [mailto:owner-rsgb_lf_group@blacksheep.org]Namens Andy Talbot Verzonden: dinsdag 2 augustus 2011 17:44 Aan: rsgb_lf_group@blacksheep.org Onderwerp: Re: LF: RE: frequency doubler and divider To prolong an already long thread :-) A differential line receiver of the 26xx32 and 26xx33 type gives you a good performance. It has guaranteed switching thresholds; bias both inp= ut at half way and AC couple to one of them. But also has a small amount of symmetrical hysteresis - . The '32 devices has 200mV, the '33 has 500mV= , You'll find hysteresis very advisable when you actually start radiating= a signal using the interface. A normal comparator has so much gain that i= f you were to remove the RF source, there is more than likely to be enough pick up from the antenna to feed back round and cause all sorts of spurio= us oscillations. (In my case 700 watts of 137kHz at a frequency set by the resonance of the loding coil / antenna). Having the hysteresis means a minimum signal has to arrive before there can be any square wave generate= d. Precede the comparator input with a two stage bandpass filter , Ql =3D = 10 or so, , and you should be able to feed it with any waveform in the knowledg= e a nice 50% square wave out will result. Andy www.g4jnt.com On 2 August 2011 15:55, wrote: Hi Stefan,Rik, i didn't want to make the story too long,but i agree with you. 73 gl Victor -----Oorspronkelijk bericht----- Van: owner-rsgb_lf_group@blacksheep.org [mailto:owner-rsgb_lf_group@blacksheep.org]Namens Stefan Sch=E4fer Verzonden: maandag 1 augustus 2011 19:04 Aan: rsgb_lf_group@blacksheep.org Onderwerp: Re: LF: RE: frequency doubler and divider Hi Victor, Yes, that should work too. But as Rik says, there must be a 50% duty cycle. And if it's a sine wave, using CMOS gates is not a good idea i think, because there is a wide range where the gate can switch from L= to H or H to L. So a comparator must be choosen. And so the sine wave should look clear (no modulation). Anyway thanks, these are all useful ideas that makes us a bit more creative :-) 73, Stefan/DK7FC PS: Hmmmm, indeed, not bad that idea! My PA driver has a rectangular output. I will feed that to the optocoupler stage (6N136) to prevent = EMC problems in the shack (already works sufficient). Amplified by a BC54= 8 and a transformer between + and collector to a core that comes in saturation, one could form a curve at 2x f input that has a sharp ris= ing slope and a lower falling slope. This 2x f signal should be suitable = to drive the SG3525. Ah, i'll try all that tomorrow. Hope the PA will be active next weekend :-) Am 01.08.2011 16:40, schrieb victor13@online.nl: > Hi Stefan, > > wat about a bridge rectifier with a divider? Also broadbanded? > > 73 > > Victor > > -----Oorspronkelijk bericht----- > Van: owner-rsgb_lf_group@blacksheep.org > [mailto:owner-rsgb_lf_group@blacksheep.org]Namens Stefan Sch=E4fer > Verzonden: zondag 31 juli 2011 15:06 > Aan: rsgb_lf_group@blacksheep.org > Onderwerp: LF: frequency doubler and divider > > > LF, VLF, > > I just re-invented the wheel ;-) Just by thinking i found one possi= ble > 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 inp= ut 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 yo= u > don't know about that possibility you don't know what to seach in t= he > web too. At least i haven't found that method by searching and it a= lso > wasn't discussed here in the recent time. Furthermore i never saw i= t on > a PA design by amateurs i found in the web. > > The output signal of the 4070 is then fed to the well known frequen= cy > 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_0004_01CC5147.3816FBE0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
OK=20 Andy,
 
it was=20 just an old idea,never tried it out.for lf I am using an old fasioned = class c=20 tube PA,500W from 100 to 700KHz without switching.
 
73
 
Victor
-----Oorspronkelijk bericht-----
Van:=20 owner-rsgb_lf_group@blacksheep.org=20 [mailto:owner-rsgb_lf_group@blacksheep.org]Namens Andy=20 Talbot
Verzonden: dinsdag 2 augustus 2011 = 17:44
Aan:=20 rsgb_lf_group@blacksheep.org
Onderwerp: Re: LF: RE: = frequency=20 doubler and divider

To prolong an already long thread :-)
 
A differential line receiver of the 26xx32 and 26xx33 type gives = you a=20 good performance.   It has guaranteed switching thresholds;=20 bias both input at half way and AC couple to one of them.  = But also=20 has a small amount of symmetrical hysteresis - .   The = '32=20 devices has 200mV, the '33 has 500mV,  
 
You'll find hysteresis very advisable when you actually = start=20 radiating a signal using the interface.   A normal = comparator has so=20 much gain that if you were to remove the RF source, there is more than = likely=20 to be enough pick up from the antenna to feed back round and cause all = sorts=20 of spurious oscillations.  (In my case 700 watts of 137kHz at a = frequency=20 set by the resonance of the loding coil / antenna).  Having the=20 hysteresis means a minimum signal has to arrive before there can be = any square=20 wave generated.  
 
Precede the comparator input with a two stage bandpass filter , = Ql =3D 10=20 or so, , and you should be able to feed it with any waveform in the = knowledge=20 a nice 50% square wave out will result.
 
Andy


 
On 2 August 2011 15:55, <victor13@online.nl> = wrote:
Hi=20 Stefan,Rik,

i didn't want to make the story too long,but i = agree with=20 you.

73 gl

Victor

-----Oorspronkelijk=20 bericht-----
Van: owner-rsgb_lf_group@bl= acksheep.org
[mailto:owner-rsgb_lf_group@bl= acksheep.org]Namens=20 Stefan Sch=E4fer
Verzonden: maandag 1 augustus 2011 19:04
Aan: = rsgb_lf_group@blacksheep.org=
Onderwerp:=20 Re: LF: RE: frequency doubler and divider


Hi = Victor,

Yes,=20 that should work too. But as Rik says, there must be a 50% = duty
cycle.=20 And if it's a sine wave, using CMOS gates is not a good idea = i
think,=20 because there is a wide range where the gate can switch from L = to
H or H=20 to L. So a comparator must be choosen. And so the sine = wave
should look=20 clear (no modulation).
Anyway thanks, these are all useful ideas = that=20 makes us a bit more
creative :-)

73, = Stefan/DK7FC

PS:=20 Hmmmm, indeed, not bad that idea! My PA driver has a = rectangular
output.=20 I will feed that to the optocoupler stage (6N136) to prevent = EMC
problems=20 in the shack (already works sufficient). Amplified by a BC548
and = a=20 transformer between + and collector to a core that comes = in
saturation,=20 one could form a curve at 2x f input that has a sharp = rising
slope and a=20 lower falling slope. This 2x f signal should be suitable to
drive = the=20 SG3525. Ah, i'll try all that tomorrow. Hope the PA will = be
active next=20 weekend :-)


Am 01.08.2011 16:40, schrieb victor13@online.nl:
> = Hi=20 Stefan,
>
> wat about a bridge rectifier with a divider? = Also=20 broadbanded?
>
> 73
>
> = Victor
>
>=20 -----Oorspronkelijk bericht-----
> Van: owner-rsgb_lf_group@bl= acksheep.org
>=20 [mailto:owner-rsgb_lf_group@bl= acksheep.org]Namens=20 Stefan Sch=E4fer
> Verzonden: zondag 31 juli 2011 = 15:06
> Aan: rsgb_lf_group@blacksheep.org=
>=20 Onderwerp: LF: frequency doubler and divider
>
>
> = LF,=20 VLF,
>
> I just re-invented the wheel ;-) Just by = thinking i=20 found one possible
> way how to double and divide a = rectangular=20 signal, to achieve an
> accurate 50 % duty cycle = :-)
>
>=20 One could take a simple XOR gatter like a CD4070 and a RC circuit.=20 The
> time constant has to be about the half of the period of = the=20 wanted
> frequency, e.g. 3.6 us for 137 kHz. The output of the = RC=20 circuit
> (voltage across C) and the original signal is fed to = one=20 single input of
> the gatter. Then the output frequency will = be 2x f=20 input.
>
> All this can be found in the internet as = well, of=20 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=20 by 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=20 known frequency
> divider consisting out of e.g. a CD4013. = Then output=20 frequency will be
> the same as on the input but the duty = cycle will=20 be accurate 50%!
>
> This is one method to (re-) obtain = a=20 suitable drive signal for a H
> bridge PA or class D PA after = passing=20 the driver signal through an
> optocoupler or so. I'm sure i = will use=20 that method now in several
> circuits, like in the new LF PA = that=20 still causes some problems,
> excactly on that = matter!
>
>=20 Later i found on the German wiki site:
> http://de.wikipedia.org/wiki/XOR-Gatter#Frequenzverdopplu= ng
>
>=20 73,=20 Stefan/DK7FC
>
>
>



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