Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-me03.r1000.mx.aol.com (Internet Inbound) with ESMTP id 73E5138000081; Sun, 31 Jul 2011 10:21:35 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1QnWsV-0000WQ-9d for rs_out_1@blacksheep.org; Sun, 31 Jul 2011 15:20:27 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1QnWsU-0000WF-KV for rsgb_lf_group@blacksheep.org; Sun, 31 Jul 2011 15:20:26 +0100 Received: from rhcavuit02.kulnet.kuleuven.be ([134.58.240.130] helo=cavuit02.kulnet.kuleuven.be) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1QnWsS-0003Tz-H4 for rsgb_lf_group@blacksheep.org; Sun, 31 Jul 2011 15:20:26 +0100 X-KULeuven-Envelope-From: rik.strobbe@fys.kuleuven.be X-KULeuven-Scanned: Found to be clean X-KULeuven-ID: D7D4112809D.A4469 X-KULeuven-Information: Katholieke Universiteit Leuven Received: from smtps01.kuleuven.be (smtpshost01.kulnet.kuleuven.be [134.58.240.74]) by cavuit02.kulnet.kuleuven.be (Postfix) with ESMTP id D7D4112809D for ; Sun, 31 Jul 2011 16:20:15 +0200 (CEST) Received: from ICTS-S-HUB-N1.luna.kuleuven.be (icts-s-hub-n1.luna.kuleuven.be [10.112.9.11]) by smtps01.kuleuven.be (Postfix) with ESMTP id 8EBC431E703 for ; Sun, 31 Jul 2011 16:20:15 +0200 (CEST) Received: from ICTS-S-EXC2-CA.luna.kuleuven.be ([10.112.11.13]) by ICTS-S-HUB-N1.luna.kuleuven.be ([10.112.9.11]) with mapi; Sun, 31 Jul 2011 16:20:15 +0200 X-Kuleuven: This mail passed the K.U.Leuven mailcluster From: Rik Strobbe To: "rsgb_lf_group@blacksheep.org" Date: Sun, 31 Jul 2011 16:20:16 +0200 Thread-Topic: LF: frequency doubler and divider Thread-Index: AcxPhf3wPDywogF5QMK9nXTX3/3PjQABYc2U Message-ID: References: <4E355332.6010107@iup.uni-heidelberg.de> ,<4E355855.8050305@iup.uni-heidelberg.de> In-Reply-To: <4E355855.8050305@iup.uni-heidelberg.de> 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-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001 Subject: RE: LF: frequency doubler and divider Content-Type: multipart/alternative; boundary="_000_BF4A524700075746A6467658DFC7102CB0B27CF1D0ICTSSEXC2CAlu_" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.0 required=5.0 tests=HTML_MESSAGE, 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-SCOLL-SCORE: 0:2:409274432:93952408 X-AOL-SCOLL-URL_COUNT: 0 x-aol-sid: 3039ac1d608b4e3564ee5736 X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none --_000_BF4A524700075746A6467658DFC7102CB0B27CF1D0ICTSSEXC2CAlu_ Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Hello Stefan, I agree with Andy. The XOR gate will produce a "spike" al the edges (rising and falling) of th= e input signal. The with of the spikes will be determined by the RC constan= t. If the duty cycle of the input signal is not 50% then the spikes will ni= t be at equal distance (in time) from each other. If you use these spikes to divide by 2 you end up with a signal with an ide= ntical duty cycle as the input signal. The solution can be to send the frequency doubled signal trough a good low = pass filter and then divide by 2. But that is as Andy explained (get rid of= the odd harmonics). 73, Rik ON7YD - OR7T ________________________________ Van: owner-rsgb_lf_group@blacksheep.org [owner-rsgb_lf_group@blacksheep.org= ] namens Stefan Sch=E4fer [schaefer@iup.uni-heidelberg.de] Verzonden: zondag 31 juli 2011 15:27 Aan: rsgb_lf_group@blacksheep.org Onderwerp: Re: LF: frequency doubler and divider Hi Andy, True. But if the goal is not to obtain a 2x f signal but an accurate 50% square w= ave drive signal at 1 x f, this must be a suitable method. And furthermore = the circuit generates a inverted signal without delay too! This is exactly = what i need for the H bridge driver (using IR2113 FET drivers) that will be= fed from the new IQ-TX converter. Before i tried a CD4093 to get the inverted signal but there was always a s= ignificant delay, causing high switching losses due to overlapping ON times= . Sure, i could try 74HC... types to reduce delay times to the usual CD4013= worked fine so far in all my PAs. 73, Stefan/DK7FC Am 31.07.2011 15:16, schrieb Andy Talbot: 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 eq= ually 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 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 out= put 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 discusse= d here in the recent time. Furthermore i never saw it on a PA design by ama= teurs i found in the web. The output signal of the 4070 is then fed to the well known frequency divid= er 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 P= A or class D PA after passing the driver signal through an optocoupler or s= o. 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-Gat= ter#Frequenzverdopplung 73, Stefan/DK7FC --_000_BF4A524700075746A6467658DFC7102CB0B27CF1D0ICTSSEXC2CAlu_ Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Hello Stefan,
 
I agree with Andy.
The XOR gate will produce a "spi= ke" al the edges (rising and falling) of the input signal. The with of= the spikes will be determined by the RC constant. If the duty cycle of the= input signal is not 50% then the spikes will nit be at equal distance (in time) from each other.
If you use these spikes to divide by = 2 you end up with a signal with an identical duty cycle as the input s= ignal.
The solution can be to send the frequ= ency doubled signal trough a good low pass filter and then divide by 2. But= that is as Andy explained (get rid of the odd harmonics).
 
73, Rik  ON7YD - OR7T
Van: owner-rsgb_l= f_group@blacksheep.org [owner-rsgb_lf_group@blacksheep.org] namens Stefan S= ch=E4fer [schaefer@iup.uni-heidelberg.de]
Verzonden: zondag 31 juli 2011 15:27
Aan: rsgb_lf_group@blacksheep.org
Onderwerp: Re: LF: frequency doubler and divider

Hi Andy,

True.
But if the goal is not to obtain a 2x f signal but an accurate 50% square w= ave drive signal at 1 x f, this must be a suitable method. And furthermore = the circuit generates a inverted signal without delay too! This is exactly = what i need for the H bridge driver (using IR2113 FET drivers) that will be fed from the new IQ-TX converter.<= br>
Before i tried a CD4093 to get the inverted signal but there was always a s= ignificant delay, causing high switching losses due to overlapping ON times= . Sure, i could try 74HC... types to reduce delay times to the usual CD4013= worked fine so far in all my PAs.

73, Stefan/DK7FC



Am 31.07.2011 15:16, schrieb Andy Talbot:
No, that doesn't work to give a true square wave.   If the R= C 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<= /div>


 
2011/7/31 Stefan Sch=E4fer <= ;schaefer@iup.uni-heidelb= erg.de>
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.<= br>
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 discusse= d 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 divid= er 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 P= A or class D PA after passing the driver signal through an optocoupler or s= o. 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


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