[hpsdr] HPSDR Context - high-level viewof how the cards fit together (DRAFT)

[Alex]

Bob,
>Some of it does not fit with what I thought was happening.

That's why I drew it. We need to make sure we're all cear and in agreement on the design.

I think we're going to need a common front-end board for CASMIR and HORTON, I'm calling that COPERNICUS.
If we want to use the front-end for MERCURY, that's good too.

Why a common front end? Because it seems a bit uneconomical duplicating bandpass filters on CASMIR and HORTON.
Why not put them on another board so if some better, faster, etc. whizbang-doohicky comes out (either a better modulator/demodulator, mixer, DAC or ADC) we don't have to scrap out the entire transmitter or receiver chain (just part of it).

So COPERNICUS has some filtering and maybe an amp. Should the mixer/modulator/demodulator be there too?
One benefit I can see is to help isolate, with a nice steel box, the mixer/modulator/demodulator and the latter portions of the RF chain from the rest of the system.

Doesn't personally matter to me which way we go, I just want to get the thing built.  : )

Alex, N3NP

----- Original Message ----
From: Robert McGwier <rwmcgwier at comcast.net>
To: Alex <harvilchuck at yahoo.com>
Cc: hpsdr at hpsdr.org
Sent: Tuesday, June 13, 2006 8:48:44 PM
Subject: Re: [hpsdr] HPSDR Context - high-level viewof how the cards fit together (DRAFT)

Alex:

Some of it does not fit with what I thought was happening.

Horton takes in analog RF and produces I/Q by doing quadrature 
integrate/sample/hold detection but then only after opposite phase 
samples have been subtracted from each other.  And like all 
unimplemented undesigned things,  it is supremely powerful and 
perfect.    ;-).  The original proposal said a QSD would be used, so I 
base my comments on that.  You show I/Q coming in from the front end.

Mercury can take in analog RF and produce I/Q since its ONLY function is 
likely to be to act as a DDC.  I supposed it could take in I/Q but I 
would personally like to see a really good argument for it before it 
made sense to me.

Casmir needs to produce RF to be amplified and mixed and if you are 
using the I/Q modulators and demodulators from AD respectively,  then it 
will produce a single analog RF output or receive a single analog input.

Did I get stuff wrong in my head?

Bob
N4HY




Alex wrote:
> ***** High Performance Software Defined Radio Discussion List *****
>
> Here's a drawing I did to try to describe how I think all the HPSDR cards fit together. 
>
> Before anyone comments, yes, JANUS isn't on the drawing. I am trying to describe a fully configured HPSDR w/o an SDR-1000 or other radio.
>
> I added it to the CASMIR part of the Wiki (http://hpsdr.org/wiki/index.php?title=HpsdrWiki:Community_Portal#CASMIR_-_0MHz_to_2.5GHz_Transmitter_Card)
>
>
> It's a draft, so constructive comments are appreciated.
>
> Alex, N3NP
>
>
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>   


-- 
AMSAT VP Engineering. Member: ARRL, AMSAT-DL, TAPR, Packrats,
NJQRP/AMQRP, QRP ARCI, QCWA, FRC. ARRL SDR Wrk Grp Chairman
Laziness is the number one inspiration for ingenuity.  Guilty as charged!





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