[hpsdr] Odyssey Active QSD Rev. A Schematic

[Marco]

At 16.06 29/09/2006, Lyle wrote:

>Note that the input voltage range of the OPA1632 when powered by a
>single +5 supply is limited to +1.5 to +4.0 VDC, and the output range
>into a 2K load is limited to +1.9 to +3.1 VDC.
>
>I don;t think you'll overdrive things, more worrisome is the possible
>need for a different supply voltage to get the range you want or need to
>drive the CODEC over its fuill range.
>
>73,
>
>Lyle KK7P

Most opamps deliver the best THD and IMD for Vout<Vs/3. So if you 
want to drive the CODEC at 0/+3V the good idea would be to allow 
something like -5/+10V supply to the OPA1632 and clamp diodes to 0 
and 3V at the CODEC input.

I started assembling a modified SoftRock frontend with the Odyssey 
mixer and raised opamp supply to evaluate the IMD changes.

73 - Marco IK1ODO



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