No subject
Sat May 23 14:26:19 CDT 2009
PMOD-AD1 (dual 12-bit 1Ms/s A/D) for 24.99.
PMOD-DA2 (dual 12-bit 100ks/s D/A) for 24.99
NOTE: I am NOT recommending these boards for actual SDR work, as their
speed is too slow. But, to do some simple testing, especially at audio
frequencies, they might be of interest. Digilent also has plenty of other
cool modules that plug into the Nexys2 FPGA demonstration board.
The D/A that I mentioned is the AD9744, available for about $15 from
Digikey. It's a 14-bit, 320ms/s (I think) D/A converter. It should be
simple enough to make a small RF exciter with this chip. I just received a
few little carrier boards that this chip can soldered to that make
experimental construction simpler.
The 12-bit A/D receiver chip that John Schwacke uses is the Burr Brown
AFEDRI9201, Digikey part # 296-21570-1-ND, cost is around $8.75. Note that
there are real limitations to this chip, but it is good enough to learn SDR
techniques. Some of the limitations can be overcome with band pass
filtering, and gain control over the LNA in front of the chip. While the
chip has a 80Ms/s sampling rate, John has used a small 2M preamp/filter in
front of it, and subsampled the 2M FM repeaters with great luck. As shown
today, it also subsamples the FM broadcast band pretty easily as well.
The design that uses this receiver chip, and another chip for DSP is
actually from OH2NLT, not ON2NLT. His web site is:
http://www.kolumbus.fi/juha.niinikoski/Digital_RX/Digital_RX.htm
More info as I can.
Terry
WB4JFI
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<p class=3DMsoNormal><font size=3D2 face=3DArial><DEFANGED_span style=3D'fo=
nt-size:10.0pt;
font-family:Arial'>First of all, this is a test while I’m on vacation=
. I
hope it goes through. The following is information regarding the SDR
discussion at tacos and the post-tacos board meeting today.<o:p></o:p></DEF=
ANGED_span></font></p>
<p class=3DMsoNormal><font size=3D2 face=3DArial><DEFANGED_span style=3D'fo=
nt-size:10.0pt;
font-family:Arial'><o:p> </o:p></DEFANGED_span></font></p>
<p class=3DMsoNormal><font size=3D2 face=3DArial><DEFANGED_span style=3D'fo=
nt-size:10.0pt;
font-family:Arial'>The web site for Dr. John Schwacke’s board (from t=
he <DEFANGED_st1:place
w:st=3D"on"><DEFANGED_st1:City w:st=3D"on">Charleston</DEFANGED_st1:City>, =
<DEFANGED_st1:State w:st=3D"on">SC</DEFANGED_st1:State></DEFANGED_st1:place>
chapter) info is:<o:p></o:p></DEFANGED_span></font></p>
<p class=3DMsoNormal><font size=3D2 face=3DArial><DEFANGED_span style=3D'fo=
nt-size:10.0pt;
font-family:Arial'><a href=3D"http://www.sdrtrack.drupalcafe.com/">http://w=
ww.sdrtrack.drupalcafe.com/</a><o:p></o:p></DEFANGED_span></font></p>
<p class=3DMsoNormal><font size=3D2 face=3DArial><DEFANGED_span style=3D'fo=
nt-size:10.0pt;
font-family:Arial'><o:p> </o:p></DEFANGED_span></font></p>
<p class=3DMsoNormal><font size=3D2 face=3DArial><DEFANGED_span style=3D'fo=
nt-size:10.0pt;
font-family:Arial'>The web site for the (HPSDR) openhpsdr stuff is:<o:p></o=
:p></DEFANGED_span></font></p>
<p class=3DMsoNormal><font size=3D2 face=3DArial><DEFANGED_span style=3D'fo=
nt-size:10.0pt;
font-family:Arial'><a href=3D"http://www.openhpsdr.com/">www.openhpsdr.com<=
/a><o:p></o:p></DEFANGED_span></font></p>
<p class=3DMsoNormal><font size=3D2 face=3DArial><DEFANGED_span style=3D'fo=
nt-size:10.0pt;
font-family:Arial'><o:p> </o:p></DEFANGED_span></font></p>
<p class=3DMsoNormal><font size=3D2 face=3DArial><DEFANGED_span style=3D'fo=
nt-size:10.0pt;
font-family:Arial'>The web site for the Digilent Nexys2 FPGA board is:<o:p>=
</o:p></DEFANGED_span></font></p>
<p class=3DMsoNormal><font size=3D2 face=3DArial><DEFANGED_span style=3D'fo=
nt-size:10.0pt;
font-family:Arial'><a
href=3D"http://www.digilentinc.com/Products/Detail.cfm?Prod=3DNEXYS2">http:=
//www.digilentinc.com/Products/Detail.cfm?Prod=3DNEXYS2</a><o:p></o:p></DEF=
ANGED_span></font></p>
<p class=3DMsoNormal><font size=3D2 face=3DArial><DEFANGED_span style=3D'fo=
nt-size:10.0pt;
font-family:Arial'><o:p> </o:p></DEFANGED_span></font></p>
<p class=3DMsoNormal><font size=3D2 face=3DArial><DEFANGED_span style=3D'fo=
nt-size:10.0pt;
font-family:Arial'>I would get the board with the larger FPGA, as you don&#=
8217;t
want to get partway through a design, and find out that you don’t have
enough room in the FPGA.<o:p></o:p></DEFANGED_span></font></p>
<p class=3DMsoNormal><font size=3D2 face=3DArial><DEFANGED_span style=3D'fo=
nt-size:10.0pt;
font-family:Arial'><o:p> </o:p></DEFANGED_span></font></p>
<p class=3DMsoNormal><font size=3D2 face=3DArial><DEFANGED_span style=3D'fo=
nt-size:10.0pt;
font-family:Arial'>From there, you can also find the accessory A/D and D/A =
boards
(under products, peripheral modules). I think they are:<o:p></o:p></D=
EFANGED_span></font></p>
<p class=3DMsoNormal><font size=3D2 face=3DArial><DEFANGED_span style=3D'fo=
nt-size:10.0pt;
font-family:Arial'>PMOD-AD1 (dual 12-bit 1Ms/s A/D) for 24.99.<o:p></o:p></=
DEFANGED_span></font></p>
<p class=3DMsoNormal><font size=3D2 face=3DArial><DEFANGED_span style=3D'fo=
nt-size:10.0pt;
font-family:Arial'>PMOD-DA2 (dual 12-bit 100ks/s D/A) for 24.99<o:p></o:p><=
/DEFANGED_span></font></p>
<p class=3DMsoNormal><font size=3D2 face=3DArial><DEFANGED_span style=3D'fo=
nt-size:10.0pt;
font-family:Arial'><o:p> </o:p></DEFANGED_span></font></p>
<p class=3DMsoNormal><font size=3D2 face=3DArial><DEFANGED_span style=3D'fo=
nt-size:10.0pt;
font-family:Arial'>NOTE: I am NOT recommending these boards for actua=
l SDR
work, as their speed is too slow. But, to do some simple testing, esp=
ecially
at audio frequencies, they might be of interest. Digilent also has pl=
enty of
other cool modules that plug into the Nexys2 FPGA demonstration board.<o:p>=
</o:p></DEFANGED_span></font></p>
<p class=3DMsoNormal><font size=3D2 face=3DArial><DEFANGED_span style=3D'fo=
nt-size:10.0pt;
font-family:Arial'><o:p> </o:p></DEFANGED_span></font></p>
<p class=3DMsoNormal><font size=3D2 face=3DArial><DEFANGED_span style=3D'fo=
nt-size:10.0pt;
font-family:Arial'>The D/A that I mentioned is the AD9744, available for ab=
out
$15 from Digikey. It’s a 14-bit, 320ms/s (I think) D/A converte=
r. It
should be simple enough to make a small RF exciter with this chip. I =
just
received a few little carrier boards that this chip can soldered to that ma=
ke experimental
construction simpler.<o:p></o:p></DEFANGED_span></font></p>
<p class=3DMsoNormal><font size=3D2 face=3DArial><DEFANGED_span style=3D'fo=
nt-size:10.0pt;
font-family:Arial'><o:p> </o:p></DEFANGED_span></font></p>
<p class=3DMsoNormal><font size=3D2 face=3DArial><DEFANGED_span style=3D'fo=
nt-size:10.0pt;
font-family:Arial'>The 12-bit A/D receiver chip that John Schwacke uses is =
the
Burr Brown AFEDRI9201, Digikey part # 296-21570-1-ND, cost is around $8.75.=
Note that there are real limitations to this chip, but it is good enough to
learn SDR techniques. Some of the limitations can be overcome with ba=
nd pass
filtering, and gain control over the LNA in front of the chip. While =
the chip
has a 80Ms/s sampling rate, John has used a small 2M preamp/filter in front=
of
it, and subsampled the 2M FM repeaters with great luck. As shown toda=
y, it
also subsamples the FM broadcast band pretty easily as well.<o:p></o:p></DE=
FANGED_span></font></p>
<p class=3DMsoNormal><font size=3D2 face=3DArial><DEFANGED_span style=3D'fo=
nt-size:10.0pt;
font-family:Arial'><o:p> </o:p></DEFANGED_span></font></p>
<p class=3DMsoNormal><font size=3D2 face=3DArial><DEFANGED_span style=3D'fo=
nt-size:10.0pt;
font-family:Arial'>The design that uses this receiver chip, and another chip
for DSP is actually from OH2NLT, not ON2NLT. His web site is:<o:p></o=
:p></DEFANGED_span></font></p>
<p class=3DMsoNormal><font size=3D2 face=3DArial><DEFANGED_span style=3D'fo=
nt-size:10.0pt;
font-family:Arial'><a
href=3D"http://www.kolumbus.fi/juha.niinikoski/Digital_RX/Digital_RX.htm">h=
ttp://www.kolumbus.fi/juha.niinikoski/Digital_RX/Digital_RX.htm</a><o:p></o=
:p></DEFANGED_span></font></p>
<p class=3DMsoNormal><font size=3D2 face=3DArial><DEFANGED_span style=3D'fo=
nt-size:10.0pt;
font-family:Arial'><o:p> </o:p></DEFANGED_span></font></p>
<p class=3DMsoNormal><font size=3D2 face=3DArial><DEFANGED_span style=3D'fo=
nt-size:10.0pt;
font-family:Arial'>More info as I can.<o:p></o:p></DEFANGED_span></font></p>
<p class=3DMsoNormal><font size=3D2 face=3DArial><DEFANGED_span style=3D'fo=
nt-size:10.0pt;
font-family:Arial'>Terry<o:p></o:p></DEFANGED_span></font></p>
<p class=3DMsoNormal><font size=3D2 face=3DArial><DEFANGED_span style=3D'fo=
nt-size:10.0pt;
font-family:Arial'>WB4JFI<o:p></o:p></DEFANGED_span></font></p>
<p class=3DMsoNormal><font size=3D2 face=3DArial><DEFANGED_span style=3D'fo=
nt-size:10.0pt;
font-family:Arial'><o:p> </o:p></DEFANGED_span></font></p>
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