[hpsdr] ISD Theory References?

[Cecilio Bayona]

Rob Frohne wrote:
> ***** High Performance Software Defined Radio Discussion List *****
> 
> 
> 
> ------------------------------------------------------------------------
> 
> Hi,
> 
> Pardon my ignorance; I haven't been party to all the discussion going on 
> with the ISD, and I'd like to be brought up to speed.  A Google search 
> for "Integrating Sampling Detector" reveals only one hit, the Pheonix 
> wiki page.  It seems that a number of people here on the list are 
> convinced that it is better than a QSD or commutating mixer.  It appears 
> that Ahti isn't completely happy with his experimental results.   Phil 
> has some simulation results on his blog page, but examining the 
> simulation requires Windows and I'm a Linux guy.  Gerald has a 
> description of the QSD in his first article:
> http://www.flex-radio.com/articles_files/SDRFMP1.pdf
> 
> Referring to Figures 10 and 11 of that article.  Are we replacing the 
> leaky integrators (RC low pass filter )with an ideal integrator and 
> varying the time it is connected?   I'd like to see a block diagram.  
> Ahti's circuit sure looks a lot like the block diagram and simple 
> circuit described in Gerald's article (Figure's 10 and 11) to me.  So 
> what exactly are the differences between a QSD and an ISD?
> 
> What are the theoretical advantages/disadvantages of an ISD over a 
> commutating mixer, or a QSD?
> Maybe if I understood all the above, I could make some progress on 
> understanding why Ahti's circuit isn't as good as expected, which is 
> needed to advance the Pheonix project, and I'm interested in that.  :-)
> 
> 73 and thanks for bearing with me,
> 
> Rob, KL7NA
> 
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LTSpice can be installed under Wine and runs fine, that way you can try 
the circuits out, and experiment with changes.


-- 

Cecil
KD5NWA
www.qrpradio.com www.hpsdr.com


"Sacred Cows make the best Hamburger!"	Don Seglio Batuna


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