[hpsdr] New Mercury block diagram

[Henry Vredegoor]

Hi Phil, All,

Thank you for your reply!

Yes, as far as I can see, the drawing is OK, at least for the analog
HF-part, which had my focus at this point.
I'll have to study the other parts a little more.

I did see the possibility of setting every switch in bypass of course.
But I think I would have liked a separate input connection more! (Sorry....)

My preferred setup would be something like:
- Separate "independent" connector, for the "internal world" [As Eric -
AA4SW would say  ;-) ]
- ADC input selectable by hardware straps for either on-board or off-board
analog HF
- The advantage of not having the (min.) 4 dB insertion loss penalty of the
8 Hittite switches.
- Fully differential, 200 Ohm (or 50 Ohm with 1:4 transformer, galvanic
isolation) input to the ADC

You could also leave out the analog HF parts completely if I where a
bare-board builder and would want to roll my own version of HF filters and
-amplifiers.

But anyway, that's just my 2 cents worth opinion!
I like Mercury as it is looking right now very much, and I surely can live
with the current setup!
I don't want to criticize your very good work in any way!

Thank you, looking forward to see more of Mercury!


73's,

Henry.



> -----Original Message-----
> From: pvharman at arach.net.au [mailto:pvharman at arach.net.au] 
> Sent: dinsdag 17 april 2007 9:49
> To: Henry Vredegoor
> Cc: hpsdr at hpsdr.org
> Subject: Re: [hpsdr] New Mercury block diagram
> 
> 
> Hi Henry,
> 
> That was my intention - if you set the RF switches in the 
> correct positions 
> then the only item between the antenna and the LT2208 is the 
> attenuator and 
> that can be set to 0dB. 
> 
> That is also the way the current circuit is drawn. As far as 
> I can see the 
> block diagram is correct?
> 
> 73's Phil...VK6APH 
> 
> 
> Quoting Henry Vredegoor <henry.vredegoor at gmail.com>:
> 
> > ***** High Performance Software Defined Radio Discussion List *****
> > 
> > 
> 
> Hi All, Phil & Phil, 
>  
>  
> When studying the new block diagram of Mercury on the Wiki 
> pages, I noticed 
> that the configuration of the analog HF input path has changed.
>  
> Would it be an idea to bring the input to the ADC out on a 
> separate connector, 
> bypassing the on-board filtering, HF amps etc. and enabling 
> it to be used as 
> a "bare"  ADC board for e.g.. under sampling of 2 meter (0,7 
> cm) VHF etc. (The 
> input bandwidth of the ADC going up to 700 MHz) or with a 
> complete different 
> set of HF amps, filters etc?
> Maybe include a (bypassable) 1:4 broadband transformer to 
> step up from 50 to 
> the ADC's 200 Ohm impedance?
>  
> Sorry if this is already mentioned before, could not find it 
> in the archives.
>  
> 73's,
>  
> Henry.
> 


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