The 95S-1A was one of the three radios at Dayton 1997
that caught my intrest. The other two were the RX-320,
and the Kachina 505, I now have two of the 3, .....
hmmm could a 95S-1a be far behind??? ;). I couldn't
help but be intriqued by a multi kilobuck direct
conversion rig.
Duane
N9DG
--- Adam Farson <farson@shaw.ca> wrote:
> <<...Tayloe quadrature mixer direct to the A/D and
> DSP...>>
>
> The Rockwell-Collins 95S-1A receiver uses an
> image-reject I/Q mixer driving
> the ADC at zero IF.
>
> http://www.wa3key.com/95s1.html
>
> Best 73,
> Adam, VA7OJ/AB4OJ
> North Vancouver, BC, Canada
> http://www.qsl.net/ab4oj/
> Icom FAQ site:
> http://www.qsl.net/icom/
>
>
> -----Original Message-----
> From: tentec-admin@contesting.com
> [mailto:tentec-admin@contesting.com]On
> Behalf Of John Buck
> Sent: Wednesday, October 30, 2002 19:44
> To: tentec@contesting.com
> Subject: [TenTec] Re: TenTec digest, Vol 1 #729 - 11
> msgs
>
>
> Jim,
>
> OUCH! True but nasty. George will now have to try
> to recover. Watch out.
>
> I think an interesting alternative approach is a
> Tayloe quadrature mixer
> direct to the A/D and DSP. It seems to have
> excellent linearity and
> dynamic range and even acts as a very narrow band
> front end filter. In
> this case, the roofing filter can possibly be a
> digital brick wall low
> pass operating at the high side of the received
> bandwidth. No other
> stages are required except the 4X VFO and divider
> and some gain before
> the A/D.
>
> Aloha,
> John KH7T
>
> Jim, you wrote:
>
> The argument that filters in the front end of a
> heterodyning
> receiver are not needed if "everything" is
> absolutely linear
> is just not so. The mixer is not linear, so an
> image reject
> filter is NEEDED. And it might as well contribute
> to the
> narrowing of the spectrum of energy to be handled by
> the entire following system as well as doing the job
> of image
> and spurious signal product rejection. To imply
> that the use
> of narrow, muti-pole crystal lattice filters
> following the first
> mixer is a "cover up" for poor linear design
> characteristics
> of the front end or following stages, is just not
> being technically
> honest.
>
> Lots of words, hope this is understandable.
>
> 73, Jim KH7M
>
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