Message-ID: <366E681C214B4F78AB071DAD28D34386@GaryPC>
From: "Gary G4WGT" <g4wgt@tiscali.co.uk>
To: <rsgb_lf_group@blacksheep.org>
References: <4F68FEDF.4030201@iup.uni-heidelberg.de>
In-Reply-To: <4F68FEDF.4030201@iup.uni-heidelberg.de>
Date: Wed, 21 Mar 2012 12:37:40 -0000
MIME-Version: 1.0
Subject: LF: Re: 137 kHz transmit IQ converter schematic
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Stefan,

The link did not work for me.

73, Gary - G4WGT.


----- Original Message ----- 
From: "Stefan Schäfer" <Stefan.Schaefer@iup.uni-heidelberg.de>
To: <rsgb_lf_group@blacksheep.org>
Sent: Tuesday, March 20, 2012 10:04 PM
Subject: LF: 137 kHz transmit IQ converter schematic


> LF,
>
> I took the time to draw the circuit of my transmit IQ converter in the new 
> program i have.
> This is the circuit i use to generate my transmit signal to drive the 
> exciter of my PA. The 137 kHz signal is directly generated in this 
> circuit. It is mixed with 125 kHz internally.
> The basic idea is taken from Andy/G4JNT, tnx agn. The circuit is however 
> modified for an input frequency of 10.7...12.8 kHz which can be generated 
> by the soundcard. The 125 kHz generator can be locked to a reference 
> signal, into a PLL which isn't shown here (separate circuit). Anyway the 
> circuit is a stand alone device. The input signal level may be 0 (=100%) 
> down to -30 dB full scale of the soundcard without a change of the output 
> signal (including a safety factor of > 10 dB).
>
> http://dl.dropbox.com/u/19882028/LF/schematics/TX%20IQ%20converter.png
>
> Comments welcome.
>
> 73, Stefan/DK7FC
>
>