[hpsdr] Odyssey Siren Design

[Steven Bible]

Hello Ahti,

For Odyssey, we'll be using the TLV320AIC31 codec that Lyle found.  It have
differential inputs and outputs.  Alas, it does not have an external Vcom
voltage.  I can be set internally, but the external votage will have to be
set by resistor divider (and both should be the same voltage).  The DSP is a
dsPIC33FJ256GP710.

If all goes well, I should have a preliminary schematic of your circuit up
today for everyone to comment.  The packages the SN74LVC2G53 comes in I had
to layout in my CAD program (I am using CirCAD).  The 8-pin SSOP and VSSOP
were not in my library, so that slowed me down.  Now I should be able to
proceed.  I plan to use the larger SSOP package so that folks can hand build
the boards.

73,

- Steve, N7HPR
 (n7hpr at tapr.org)



> -----Original Message-----
> From: Ahti Aintila [mailto:oh2rz.sdr at gmail.com]
> Sent: Wednesday, September 27, 2006 9:45 PM
> To: Steven Bible
> Cc: hpsdr at hpsdr.org
> Subject: Re: [hpsdr] Odyssey Siren Design
>
>
> Steve,
>
> Now that you found the SN74LVC2G53 for me, I'm going to change over to
> that device. You just go ahead with this concept. It looks to me a
> very good compromise regarding the low power requirements.
>
> By the way, you may consider using Vcom reference voltage from the
> AK5394A for biasing the switch and the opamp.
>
> 73, Ahti OH2RZ
>
>
> On 28/09/06, Steven Bible <n7hpr at tapr.org> wrote:
> > ***** High Performance Software Defined Radio Discussion List *****
> >
> > Hello Ahti,
> >
> > Thank you very much.  You've given me more to think about.
> >
> > 1. In some more research today, I think the only other fully
> differential
> > opamp that comes close to the noise figure of the OPA1632 is
> the THS413x.
> > However, it costs almost $2.00 more than the OPA1632.  The
> OPA1632 can go
> > lower in supply voltage (+/-2.5V) whereas the THS413x is 5V (advantage
> > OPA1632).
> >
> > 2. and 3. Now I get it.  To get the sampling pulses you need,
> there is no
> > other part.  Not even a combined part.  All the combined swithes that I
> > found the clocking is common to all the switches, and that
> won't work for
> > your circuit.
> >
> > Finally, I'll try to use the SN74LVC2G53.  But I could also
> simply run the
> > SN74AUC2G53 at 2.7V.  It is only another regulator.  Your thoughts?
> >
> > I think I have enough information now, I'll continue drawing
> the schematic
> > and post it to the list soon.
> >
> > 73,
> >
> > - Steve, N7HPR
> >  (n7hpr at tapr.org)
> >
> >
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