Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-dc03.r1000.mx.aol.com (Internet Inbound) with ESMTP id 174D0380000A7; Mon, 18 Jul 2011 08:16:15 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1Qimim-0006iX-AA for rs_out_1@blacksheep.org; Mon, 18 Jul 2011 13:14:48 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1Qimil-0006iM-GW for rsgb_lf_group@blacksheep.org; Mon, 18 Jul 2011 13:14:47 +0100 Received: from mail-iw0-f171.google.com ([209.85.214.171]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1Qimii-00043U-I7 for rsgb_lf_group@blacksheep.org; Mon, 18 Jul 2011 13:14:47 +0100 Received: by iwn34 with SMTP id 34so4383742iwn.16 for ; Mon, 18 Jul 2011 05:14:37 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type; bh=yiylP7rh5ywWkiLOH7/JqQC8wyXZcdIxHcxwSYwrZuA=; b=bnwOmBTvhvpV77hBJ2ouMyU3oDP2deX0ItFJ/u926PwTq4UssLS8f1gegkrA3V24kB zuYF76FlsEEWSmSWAhcm71qrUStAwt4La2xW0k6SKHoSMZSjXv55NcQcwyc7GNnrsajJ wyczZLzS4HGnQsG67b4CBXGa92SuF3unrYMPQ= MIME-Version: 1.0 Received: by 10.42.84.18 with SMTP id j18mr6822532icl.114.1310991276163; Mon, 18 Jul 2011 05:14:36 -0700 (PDT) Received: by 10.231.206.78 with HTTP; Mon, 18 Jul 2011 05:14:36 -0700 (PDT) In-Reply-To: <4E2410BC.7070405@iup.uni-heidelberg.de> References: <4E2410BC.7070405@iup.uni-heidelberg.de> Date: Mon, 18 Jul 2011 13:14:36 +0100 Message-ID: From: Andy Talbot To: rsgb_lf_group@blacksheep.org X-Spam-Score: 0.9 (/) X-Spam-Report: autolearn=disabled,HTML_10_20=0.945,HTML_MESSAGE=0.001 Subject: Re: LF: TX converter for 137 kHz, help needed Content-Type: multipart/alternative; boundary=20cf30223cf551c31404a856f1f4 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 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: 0:2:497429632:93952408 X-AOL-SCOLL-URL_COUNT: 0 X-AOL-SCOLL-AUTHENTICATION: mail_rly_antispam_dkim-m018.1 ; domain : gmail.com DKIM : pass x-aol-sid: 3039ac1d40834e24240f5ab5 X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none --20cf30223cf551c31404a856f1f4 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable For an IQ upconverter, you need two mixers fed with SIN and COS (90 deg separated waveforms) as well as 90 degree shifted baseband inputs from a PC or audio phase shift network. Then by adding or subtracting the outputs, one sideband is cancelled and the other reinforced. See http://www.g4jnt.com/IQConverters.htm and http://www.g4jnt.com/LFUpconv.pdf Andy 'JNT 2011/7/18 Stefan Sch=E4fer > LF, > > Maybe someone can help me with an open question about IQ Mixers: > > I want to build a mixer that generates a rectangular output at 137.7 kHz > (to steer my LF PA) by using SL's digimode terminal at 12.7 kHz and addin= g > 125 kHz that i get from a down divided 8 MHz xtal (divided by a 74HC4060 = and > locked into a PLL of my GPS 10 kHz Ref.). > There are several ways to do that of course. It should be a cheep solutio= n > without special parts so i choosed a CD4052 analog switch / multiplexer a= nd > built a mixer that switches the positive and negative wave at the LO > frequency to the output. I am using 2 AF transformers (1:4 types, 1 on th= e > soundcard side) at the input to achieve a galvanic decoupling and a +/- > voltage. > When looking to the output spectrum i can see a peak at 137.7 kHz at 45 d= B > above noise. The LO peak is about 20 dB below that. But the image frequen= cy > at 112.3 kHz is just 10 dB below the 137.7 peak. So i need filters of > course. But the ditance between LO+RF and LO-RF is just 25.4 kHz and some= how > it is difficult for me to achieve a suitable Q and i have had problems wi= th > temp drifting Cs and do not like to make to much effort on the filtering. > I do not know much about IQ mixers but i had in mind that the reject the > image frequency by the design and do not need much filtering at the outpu= t. > So i read a bit about the mixers in wiki and at some webpages. I learned > that i need 90 deg shifted drive signals for such a mixer and found a > suitable circuit. Since i down divide 8 MHz in a 4060 i am easily getting= a > 500 kHz output and so i built that circuit that gives me the shifted driv= e > signals by using a CD4013 (2x D flipflop). Now i already have the 125 kHz= IQ > drive signals and found a circuit how to arrange a suitable mixer at > http://www.elexs.de/iq1.htm and/or http://www.yu1lm.qrpradio.com/** > DR2B%20HF%20SDR%20RECEIVER-**YU1LM.pdf > > But the question is where do i get my 137.7 kHz signal now? There are 4 > "cables" that come out of this mixer type, 2 pairs that are fed to a summ= er. > Then i have the I and Q output that is fed to the soundcard in these > examples. Somehow it begins to dawn on me that i will not get the wanted > signal on the mixers output, right?`The signals can be calculated in a > suitable PC software, which is no solution for me here of course. I would= go > on experimenting and will find the solution on the topic of course but > anyway i want to ask here before since i know that there is someone who > knows the answer. > > Is there no chance to easily reject the image frequency or do i have to > spend the filtering effort? If there is a complete hardware solution (no > programmable devices, no software), please tell me :-) > > The TX mixer should then allow me to remote steer my LF TX and even make > QSY, i.e. decide to call CQ at 137.71 kHz and if no one replies, make QSY= to > beacon mode at 136.17x kHz for example. At the output i want to add a OP > device or comparator that forms a rectangular wave to drive the PA. Later= i > want to add a AM circuit that filteres the 12.7 kHz and provides a variab= le > DC voltage that will steer the PA's SMPS step down converter to allow > QRO/QRP by varying the volume at the PC... > > Tnx in advance. > > 73, Stefan/DK7FC > > --20cf30223cf551c31404a856f1f4 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable
=A0
For an IQ upconverter, you need two mixers fed with SIN and COS (90 de= g separated waveforms) as well as=A090 degree shifted baseband inputs from = a PC or audio phase shift network.=A0 Then by adding or subtracting the out= puts, one sideband is=A0cancelled and the other reinforced.
=A0
Andy
'JNT


=A0
2011/7/18 Stefan Sch=E4fer <= ;schaefer@iup.uni-heidelb= erg.de>
LF,

Maybe someone can hel= p me with an open question about IQ Mixers:

I want to build a mixer = that generates a rectangular output at 137.7 kHz (to steer my LF PA) by usi= ng SL's digimode terminal at 12.7 kHz and adding 125 kHz that i get fro= m a down divided 8 MHz xtal (divided by a 74HC4060 and locked into a PLL of= my GPS 10 kHz Ref.).
There are several ways to do that of course. It should be a cheep solution = without special parts so i choosed a CD4052 analog switch / multiplexer and= built a mixer that switches the positive and negative wave at the LO frequ= ency to the output. I am using 2 AF transformers (1:4 types, 1 on the sound= card side) at the input to achieve a galvanic decoupling and a +/- voltage.=
When looking to the output spectrum i can see a peak at 137.7 kHz at 45 dB = above noise. The LO peak is about 20 dB below that. But the image frequency= at 112.3 kHz is just 10 dB below the 137.7 peak. So i need filters of cour= se. But the ditance between LO+RF and LO-RF is just 25.4 kHz and somehow it= is difficult for me to achieve a suitable Q and i have had problems with t= emp drifting Cs and do not like to make to much effort on the filtering. I do not know much about IQ mixers but i had in mind that the reject the im= age frequency by the design and do not need much filtering at the output. S= o i read a bit about the mixers in wiki and at some webpages. I learned tha= t i need 90 deg shifted drive signals for such a mixer and found a suitable= circuit. Since i down divide 8 MHz in a 4060 i am easily getting a 500 kHz= output and so i built that circuit that gives me the shifted drive signals= by using a CD4013 (2x D flipflop). Now i already have the 125 kHz IQ drive= signals and found a circuit how to arrange a suitable mixer at http://www.elexs.de/iq1.htm<= /a> and/or http://www.yu1lm.qrpradio.com/DR2B%= 20HF%20SDR%20RECEIVER-YU1LM.pdf

But the question is where do i get my 137.7 kHz signal now? There are 4= "cables" that come out of this mixer type, 2 pairs that are fed = to a summer. Then i have the I and Q output that is fed to the soundcard in= these examples. Somehow it begins to dawn on me that i will not get the wa= nted signal on the mixers output, right?`The signals can be calculated in a= suitable PC software, which is no solution for me here of course. I would = go on experimenting and will find the solution on the topic of course but a= nyway i want to ask here before since i know that there is someone who know= s the answer.

Is there no chance to easily reject the image frequency or do i have to= spend the filtering effort? If there is a complete hardware solution (no p= rogrammable devices, no software), please tell me :-)

The TX mixer s= hould then allow me to remote steer my LF TX and even make QSY, i.e. decide= to call CQ at 137.71 kHz and if no one replies, make QSY to beacon mode at= 136.17x kHz for example. At the output i want to add a OP device or compar= ator that forms a rectangular wave to drive the PA. Later i want to add a A= M circuit that filteres the 12.7 kHz and provides a variable DC voltage tha= t will steer the PA's SMPS step down converter to allow QRO/QRP by vary= ing the volume at the PC...

Tnx in advance.

73, Stefan/DK7FC


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