[hpsdr] Odyssey Active QSD Rev. A Schematic

[Steven Bible]

Hi Alberto,

As Ahti mentioned, yes, this design is intended to drive the TI codec
TLV320AIC31.  The codec's analog input voltage is 3.3V.  So there's actually
a fear that it may be overdriven.  The TI codec have fully differential
input and output, but the power supplies are all unipolar.  So hopefully the
ISD design is a good fit for this codec (or vice versa).

73,

- Steve, N7HPR
 (n7hpr at tapr.org)


> -----Original Message-----
> From: hpsdr-bounces at hpsdr.org [mailto:hpsdr-bounces at hpsdr.org]On Behalf
> Of Ahti Aintila
> Sent: Friday, September 29, 2006 6:31 AM
> To: Alberto I2PHD
> Cc: hpsdr at hpsdr.org
> Subject: Re: [hpsdr] Odyssey Active QSD Rev. A Schematic
>
>
> ***** High Performance Software Defined Radio Discussion List *****
>
> On 29/09/06, Alberto I2PHD <i2phd at weaksignals.com> wrote:
> > ***** High Performance Software Defined Radio Discussion List *****
> , but the two opamps have their inputs biased at 2.5V and the supply
> voltage is 5V,
> > single-rail. Given that good sound cards can happily accepts up
> to 4V and more of signal, isn't a design that limits its
> > output to 2.5Vp incapable of fully exploiting the dynamic
> offered by the sound card itself ?
> > Wouldn't a ±15V as supply voltage be more adequate for an
> uncompromised design ?
> >
> > 73  Alberto  I2PHD
>
> Alberto,
>
> You are absolutely right, but in this case the circuit is designed for
> a low power application using a bare CODEC circuit instead of the
> sound card.
>
> In other applications I really would use ±5 V or higher supply,
> preferably ±15 V.
>
> 73, Ahti OH2RZ
>
> >
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