[hpsdr] Odissey QSD circuit diagram

[Giancarlo Moda]

--- Jim Miller <jim at jtmiller.com> wrote:

> sorry
> 
> i was referring to the odissey post. it mentioned a
> similarity to phil's.
> 
> this is getting very confusing with the "integrator
> with a twist" messages.
> 
> can anyone explain with clarity what the "new
> integrator" is and how it 
> works?
> 
> tnx
> jtm 
> 

Hi Jim,

it is important we do reduce confusion ... I am one of
those that can confuse ...hi

Maybe someone that has been involved in the project
from the beginning has everything clear in his mind.

My comments, were for the HPSDR Project Odissey active
QSD circuit diagram as reported  by OH2RZ and N2HPR.

I have redrawn a similar circuit, I believe it has the
same features, but all ICs powered at +5V.

The two 2G53 have been replaced by the FST3125, driven
by the 74ACT74 Digital Quadrature Generator. The
active main parts are still the OPA1632D.
The X.O uses the 74AC86 and has switched selection for
X.O. or external L.O. The 74AC86 are OK up to 60MHz
and over. The FST3125 has no critical use as the input
is at 10.7MHz IF. Also the 74ACT74 has no problems for
clock.

If anyone is interested for curiosity ... this is a
way we learn, share and avoid mistakes... I have
posted the circuit diagram in 
http://it.groups.yahoo.com/group/Ciao_Radio_newsgroup_/files/
 look for FST3125_Active_QSD.pdf file

to see if other colleagues may interested to
experiment with active QSD.

I am too interested to see the circuit diagram of
Phil's Active QSD with a twist.

73 and have a nice weekend

Gian
I7SWX



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