Re: [Discuss-gnuradio] Are microtune 4707's worth having?

[Eric Blossom]

On Wed, Nov 10, 2004 at 02:41:38AM -0500, Tom Huppi wrote:
> 
> There are a box of 108pc on e-bay w/ no bids for $50.
> 
> I'm sorry for my lack of knowledge.  I see more IF info related to
> the 49xx pieces (on microtune's websiite), but one of the USRP
> modules seems to have a 4702.

I sent a message to the seller asking for a data sheet.
I'll let you know what I find out. 


> Unrelated general question:  If, while I wait for the USRP to
> become available, I work at modifying a cheap radio to provide
> 12khz IF output, will I be able to use the rig for anything of
> interest using currently written code?  I've seen a couple of such
> mods seemingly aimed at DRM/soundcard experimenters.

Sound cards have relatively slow A/D's in them, so you're limited to 
the bandwidth you handle.  SSB or narrow band FM are possible.

> The link to the diagram for a simple downconversion device that I
> found on the GnuRadio website left this newbie with more questions
> than answers....and I can't figure out what a 'haxpertise' is or
> where to find info on it...google draws a blank (saved the
> GnuRadio website :)

I'd translate haxpertise as "hacker expertise" == cluefulness.
Feel free to edit the wiki for clarity ;-)

> Also I have not learned enough to understand
> the relationship between signal transmission frequencies (and
> various modulation types) and the AD sampling rate needed to do
> something usefull with them.

The Nyquist criterion specifies that your sampling rate needs to be at
least 2 times the bandwidth of interest.  In reality, a number closer
to 2.5 works better.


If you haven't already, take at look at http://comsec.com/wiki?SuggestedReading
Lots of good sources of information there.

Eric