RE: [linrad] re: CS5396

[chrisalbertson90278@xxxxxxxxxxxxxxxx>]

Have you looked at the Maxim ADC chips.  Prices in the range
of US$60 for one unit but they will ship free samples if you
ask.  They make ADC specifically for sampeling RF or IF
frequency.  The "MAX1200" for example does 16-bits at
one megasample rate.  If you can go with less bits (8) you can
get sample rates at 60Mhz.  see www.maxim-ic.com

I have worked on a few radar projects (which now that I think of
it) were actually software radios.  We sampled in quadarure at
the tens of megasample rate at 8-bits and performed synthethic
aperature algorithum in software.  

The computers we used at the time (12 or 14 years ago) were about
as powerful as today's PCs but had better I/O capability.

OK, let me backup.

I thought it might be possible to home brew a software radio
that decoded most modes.  I looked around and found this project.
I also found the softmodem drivers built into Linux.  Both projects
are built around sound cards.  The problem is sound cards have,
and no surprize, audio bandwidths.    I think sound cards will
always have limited bandwidth.  So I thought about looking into
digital video then found that the chip makers already are thinking
about supporting software radio and the component prices are not
unreasonable either.  

--- Leif_Asbrink <leif.asbrink@xxxxxxxxxxxxxxxxxx> wrote:
> Hi Toki,
> 
> > > Thanks to Pete, KC1HR I now know that there is an ADC
> > > chip CS5396 from (http://www.cirrus.com).
> > >
> > > This is a 24 bit 96kHz stereo AD converter and there
> > > is an evaluation board for it.
> > >
> > > The CS5396 is 20dB better than the Delta 44!!
> > 
> > What does make you so happy ?
> Simply that this information was new to me:-)
> 
> Even after modifying the Delta44 to actually give the
> full performance of the AK4524VF, the Delta44 is limiting
> Linrad performance with the WSE RX2500.
> 
> > Almost every companies that develop ADC device have evaluation
> board
> > for their products.
> > 
> > For example;
> > You can get information about evaluation board of the most advanced
> > AD converter from;
> > 
> >      http://www.asahi-kasei.co.jp/akm/
> >
> > AK5394A is a 24 bit 192kHz stereo AD converter with s/n 123db.
> > The evaluation board also has printer, coax, and optic interfaces
> like
> > cirrus.
> Now you make me even more happy:-)
> 
> The technology is there - it only remains to learn how to use it!
> (How to get four channels of data into an application under Linux)
> 
> > I don't believe the cirrus can develop better analog device than
> the akm.
> There is one problem with AKM though. I was told by their
> representative
> here in Sweden that I can only buy AKM ICs in full reels,
> 3000 pieces if I remember correctly:-(
> 
> > Anyway, problem is always the cost.
> I did not find any info on the cost for either evaluation board but
> I would not be surprised if it could compete well with the
> corresponding
> professional audio cards.
> 
> I will stay with the Delta44 for now, with some luck someone else
> will find a way to get better data into the PC.
> 
> 73
> 
> Leif / SM5BSZ
> 


=====
Chris Albertson 
  Home:   310-376-1029  chrisalbertson90278@xxxxxxxxx
  Cell:   310-990-7550
  Office: 310-336-5189  Christopher.J.Albertson@xxxxxxxx

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