DSP etc
C-Lab
c_lab@msn.com
Mon, 31 Dec 2001 17:29:28 -0500
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Hello,
I recently "caught the bug" after visiting with Frank G
this Thanksgiving, and am interested in participating/helping,
that is, if you guys will tolerate a non-ham. I suppose I
could be called a pro, instead, because I did indeed design
interesting DSP-radio things for "the government" some
20+ years ago -- back when one did this with wire-wrapped
TRW multipliers and homebrew cpu's in general. It's a lot=20
easier these days! Since then, I formed a company that=20
does DSP consulting work.
We do embedded DSP (mainly using the TI stuff) and windoze
programming (from drivers on up, we _DO_ Windows) for
a living here at our solar powered facility in Floyd, VA.
We also do general embedded uP stuff, mainly using PIC
uP's for lots of interesting things.
Here, we actually have enough room to make a for-real antenna
at LF if we wanted to do it, and there's no powerlines for
at least 1/3 mile in any direction...could be interesting!
I can of course turn off any locally generated electrical noise,
since *I* am the power company for these 30 acres.
Last time I hooked up a SW receiver it was pretty nice.
I was impressed enough with Frank's setup to get started
duplicating it, all the stuff is on order and on the way,
or will be very soon. (Someone needs to make that
cool antenna a kit item and sell it!!! What a pain to
chase all that stuff down!)
It did seem to me that the DSP on the tentec was in need
of assistance. There are a number of possibilities I'm looking
into for helping it along. Most of them would include tapping
the signal off at the low IF before the builtin DSP sees it,
since there you have some room to work and do more interesing
stuff. I note that the higher quality pc soundcards (the only
type worth it, the normal SB clones have serious built-in birdie
troubles, due to "nearest neighbor" builtin resampling and
other bad design jokes) now support 48k sample rates....
My company also makes a DSP card that will support just about=20
any serial a/d out there as long as you provide the timing signals --=20
the board just has a sync serial port that can go 10+mbits.
One approach would be simply to ditch their dsp card and replace it
either with code on the PC/soundcard, or another dsp card=20
with some for-real horsepower. This latter could be done
such that the radio remained back-compatable with existing
control programs, but would allow for smarter control
programs to tell it to do "more interesting" things. By adding
autobaud software it would be easy to tell if the control
program was original (1200 baud) or something "new",
(some faster baud rate, gheesh) for example.=20
Plans include adding modes (costas loop "am stereo", nbfm
fsk psk etc etc etc) and some *good* noise removal using some
DSP tricks we've learned over the last 20 years of "practicing".
Better (and maybe adaptive) filters are of course obvious
and also easy to do.
For those PC-averse, or who want to be able to use laptops
which aren't all that fast, we could roll a for-real DSP board
to replace the existing one in the ten-tec. In fact, we have
at the moment a "DSP core" design that we use for proto work
that would make it easy to test embedded code. It lives in
an ISA slot, and has "everything" you could think of for doing
DSP -- 4 ch of a/d,d/a...half a meg of dword-wide static ram,
64megs flash, 5 serial ports (one is 5 mbit) and so forth and
so on. Oh yeah, it has a 150 mhz TI 'C33 on it, which we
find is a bit faster than a top of the line pentium for DSP -- it
does several things per cycle instead of the other way 'round. =20
And it runs my opsys, not windoze, so nothing is wasted.
Our main customer rolled this up to our specs and we use
it for prototyping for their designs which can then be put=20
into production fast by simply removing the stuff that project
didn't need. Yes, there are windoze drivers (and all types of=20
windoze too, not just the 9x/dos variants) and plenty of
debugging tools we've written over the years.=20
I'm not sure what your main needs/desires are, but I'm planning
on doing this anyway, and would of course be glad to share
it with all. (It gets boring doing things like Voice over IP etc
for a living...telephones!) I also have some interest in spread
spectrum (hopping)...if the tentec can't switch fast enough,
do you suppose guys would be willing to get "a couple"
and hook them up so the switching time could be hidden?
(Some of my other hobbies include astronomy and benchrest
shooting, and there, people will spend the dough to get
what they want, no question at all.)
Not sure what resume I'd give, but you might look up my book,=20
Digital Audio Processing (Doug Coulter) on Amazon.com
for a hint. It might even be worth buying for the "free" code
which includes a complete windows wavefile editor with
lots of nice windoze programming examples and plenty of
reusable DSP code (C++ and asm). Heck, if about 10,000=20
more people buy it, the publisher might even have to write=20
me a check someday...but I doubt it. Or if you can stand
a HUGE download, I can send you the code. But you'd
want the text to know how to get in there and tinker
with it I think.
What I'll probably do first is write some "shell" software
that just gets the pc soundcard going and=20
// "your dsp code goes here"
more or less. (most of the initial dsp code can be swiped
from waved, the book's "example" program) I can wrap this in an=20
appwizard for devstudio so as to make it easier to share. =20
(Most experienced programmers know better than to cut of their=20
own nose to spite Bill's face - the M$ tools are the best out=20
there, like it or not, and most computers run windoze, again,
like it or not. Heck, guess I'll just never be politically correct.)
Since the details of getting control of and using a soundcard
are arcane enough to be daunting for most, I think this
might be best? DSP and dealing with "chunked" streams
are tough enough for most people without that other overhead.
Oops, another thing I should do is put in some for-real serial
port(s) support, another non-trivial windoze thing if you need
any speed and/or control.
Comments? I'd love to hear from you guys. The phone number
is good most times, as I both live and work here, but of course
during normal business hours, I'm "at work" and can't talk long.
Doug Coulter, owner
C-Lab
c_lab@msn.com
540-763-3753
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<DIV><FONT face=3DVerdana size=3D2>Hello,</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2></FONT> </DIV>
<DIV><FONT face=3DVerdana size=3D2>I recently "caught the bug" after =
visiting with=20
Frank G</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>this Thanksgiving, and am interested =
in=20
participating/helping,</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>that is, if you guys will tolerate a=20
non-ham. I suppose I</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>could be called a pro, instead, =
because I did=20
indeed design</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>interesting DSP-radio things for "the =
government"=20
some</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>20+ years ago -- back when one did =
this with=20
wire-wrapped</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>TRW multipliers and homebrew =
cpu's in=20
general. It's </FONT><FONT face=3DVerdana size=3D2>a lot =
</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>easier these days! Since then,=20
I </FONT><FONT face=3DVerdana size=3D2>formed a company =
that </FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>does </FONT><FONT face=3DVerdana =
size=3D2>DSP=20
consulting work.</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2></FONT> </DIV>
<DIV><FONT face=3DVerdana size=3D2>We do embedded DSP (mainly using the =
TI stuff)=20
and windoze</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>programming (from drivers on up, we =
_DO_ Windows)=20
for</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>a living here at our solar powered =
facility in=20
Floyd, VA.</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>We also do general embedded uP stuff, =
mainly=20
using PIC</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>uP's for lots of interesting =
things.</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2></FONT> </DIV>
<DIV><FONT face=3DVerdana size=3D2>Here, we actually have enough room to =
make a=20
for-real antenna</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>at LF if we wanted to do it, and =
there's no=20
powerlines for</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>at least 1/3 mile in any =
direction...could be=20
interesting!</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>I can of course turn off any locally =
generated=20
electrical noise,</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>since *I* am the power company for =
these 30=20
acres.</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>Last time I hooked up a SW receiver =
it was pretty=20
nice.</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2></FONT> </DIV>
<DIV><FONT face=3DVerdana size=3D2>I was impressed enough with Frank's =
setup to get=20
started</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>duplicating it, all the stuff is on =
order and on=20
the way,</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>or will be very soon. (Someone =
needs to=20
make that</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>cool antenna a kit item and sell =
it!!! What=20
a pain to</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>chase all that stuff =
down!)</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2></FONT> </DIV>
<DIV><FONT face=3DVerdana size=3D2>It did seem to me that the DSP on the =
tentec was=20
in need</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>of assistance. There are a =
number of=20
possibilities I'm looking</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>into for helping it along. Most =
of them=20
would include tapping</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>the signal off at the low IF before =
the builtin=20
DSP sees it,</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>since there you have some room to =
work and do=20
more interesing</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>stuff. I note that the higher =
quality pc=20
soundcards (the only</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>type worth it, the normal =
SB clones have=20
serious built-in birdie</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>troubles, due to "nearest neighbor" =
builtin=20
resampling and</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>other bad design =
jokes) </FONT><FONT=20
face=3DVerdana size=3D2>now support 48k sample rates....</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2></FONT> </DIV>
<DIV><FONT face=3DVerdana size=3D2>My company also makes </FONT><FONT =
face=3DVerdana=20
size=3D2>a DSP card that will support just about </FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>any serial a/d out there =
</FONT><FONT=20
face=3DVerdana size=3D2>as long as you provide the timing signals -- =
</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>the board just </FONT><FONT =
face=3DVerdana=20
size=3D2>has a sync serial port that can go 10+mbits.</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2></FONT> </DIV>
<DIV><FONT face=3DVerdana size=3D2>One approach would be simply to =
ditch their=20
dsp card and replace it</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>either with code on the PC/soundcard, =
or another=20
dsp card </FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>with some </FONT><FONT face=3DVerdana =
size=3D2>for-real horsepower. This latter could be =
done</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>such that the radio remained =
back-compatable=20
with existing</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>control programs, but would allow for =
smarter=20
control</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>programs to tell it to do "more =
interesting"=20
things. By adding</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>autobaud software it would be easy to =
tell if the=20
control</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>program was original (1200 baud) or =
something=20
"new",</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>(some faster baud rate, gheesh) for=20
example.</FONT> </DIV>
<DIV><FONT face=3DVerdana size=3D2></FONT> </DIV>
<DIV><FONT face=3DVerdana size=3D2>Plans include adding modes (costas =
loop "am=20
stereo", nbfm</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>fsk psk etc etc etc) and some *good* =
noise=20
removal using some</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>DSP tricks we've learned over the =
last 20 years=20
of "practicing".</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>Better (and maybe adaptive) filters =
are of course=20
obvious</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>and also easy to do.</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2></FONT> </DIV>
<DIV><FONT face=3DVerdana size=3D2>For those PC-averse, or who want to =
be able to=20
use laptops</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>which aren't all that fast, we could =
roll a=20
for-real DSP board</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>to replace the existing one in the =
ten-tec. =20
In fact, we have</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>at the moment a "DSP core" design =
that we use for=20
proto work</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>that would make it easy to test =
embedded=20
code. It lives in</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>an ISA slot, and has "everything" you =
could think=20
of for doing</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>DSP -- 4 ch of a/d,d/a...half a meg =
of dword-wide=20
static ram,</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>64megs flash, 5 serial ports (one is =
5 mbit) and=20
so forth and</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>so on. Oh yeah, it has a 150 =
mhz=20
TI 'C33 on it, which we</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>find is a bit faster than a top of =
the line=20
pentium for DSP -- it</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>does several things per cycle instead =
of the=20
other way 'round. </FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>And it runs my opsys, not windoze, so =
nothing is=20
wasted.</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2></FONT> </DIV>
<DIV><FONT face=3DVerdana size=3D2>Our main customer rolled this =
up to our=20
specs and we use</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>it for prototyping for their designs =
which can=20
then be put </FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>into production fast by simply =
removing the stuff=20
that project</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>didn't need. Yes, there =
are windoze=20
drivers (and all types of </FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>windoze </FONT><FONT face=3DVerdana =
size=3D2>too, not=20
just the 9x/dos variants) and plenty of</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>debugging tools we've written over =
the=20
years.</FONT> </DIV>
<DIV><FONT face=3DVerdana size=3D2></FONT> </DIV>
<DIV><FONT face=3DVerdana size=3D2>I'm not sure what your main =
needs/desires are,=20
but I'm planning</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>on doing this anyway, and would of =
course be glad=20
to share</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>it with all. (It gets boring =
doing things=20
like Voice over IP etc</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>for a living...telephones!) I =
also have=20
some interest in spread</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>spectrum (hopping)...if the tentec =
can't switch=20
fast enough,</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>do you suppose guys would be willing =
to get "a=20
couple"</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>and hook them up so the switching =
time could be=20
hidden?</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2></FONT> </DIV>
<DIV><FONT face=3DVerdana size=3D2>(Some of my other hobbies include =
astronomy and=20
benchrest</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>shooting, and there, people will =
spend the dough=20
to get</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>what they want, no question at =
all.)</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2></FONT> </DIV>
<DIV><FONT face=3DVerdana size=3D2>Not sure what resume I'd give, but =
you might look=20
up </FONT><FONT face=3DVerdana size=3D2>my book, </FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>Digital Audio Processing (Doug =
Coulter) on=20
Amazon.com</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>for a hint. It might even be =
worth buying=20
for the "free" code</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>which includes a complete =
windows wavefile=20
editor with</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>lots of nice windoze programming =
examples and=20
plenty of</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>reusable DSP code (C++ and =
asm). Heck, if=20
about 10,000 </FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>more people </FONT><FONT =
face=3DVerdana size=3D2>buy=20
it, the publisher might even have to write </FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>me a check </FONT><FONT =
face=3DVerdana=20
size=3D2>someday...but I doubt it. Or if you can =
stand</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>a HUGE download, I can send you the =
code. =20
But you'd</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>want the text to know how to get in =
there and=20
tinker</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>with it I think.</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2></FONT> </DIV>
<DIV><FONT face=3DVerdana size=3D2>What I'll probably do first is write =
some "shell"=20
software</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>that just gets the pc soundcard going =
and=20
</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2></FONT> </DIV>
<DIV><FONT face=3DVerdana size=3D2>// "your dsp code goes =
here"</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2></FONT> </DIV>
<DIV><FONT face=3DVerdana size=3D2>more or less. (most of the =
initial dsp code=20
can be swiped</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>from waved, the book's=20
"example" program) I can wrap this in an </FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>appwizard for devstudio </FONT><FONT =
face=3DVerdana=20
size=3D2>so as to make it easier to share. </FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2></FONT> </DIV>
<DIV><FONT face=3DVerdana size=3D2>(Most experienced programmers =
</FONT><FONT=20
face=3DVerdana size=3D2>know better than to cut of their </FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>own nose to spite Bill's </FONT><FONT =
face=3DVerdana size=3D2>face - the M$ tools are the best out =
</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>there, like it or not, and most =
computers run=20
windoze, again,</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>like it or not. Heck, guess =
I'll just=20
<EM>never</EM> be politically correct.)</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2></FONT> </DIV>
<DIV><FONT face=3DVerdana size=3D2>Since the details of getting control =
of and using=20
a soundcard</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>are arcane enough to be daunting for =
most, I=20
think this</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>might be best? DSP and dealing =
with=20
"chunked" streams</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>are tough enough for most people =
without=20
that other overhead.</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2></FONT> </DIV>
<DIV><FONT face=3DVerdana size=3D2>Oops, another thing I should do is =
put in some=20
for-real serial</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>port(s) support, another non-trivial =
windoze=20
thing if you need</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>any speed and/or =
control.</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2></FONT> </DIV>
<DIV><FONT face=3DVerdana size=3D2>Comments? I'd love to hear from =
you=20
guys. The phone number</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>is good most times, as I both live =
and work here,=20
but of course</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>during normal business hours, I'm "at =
work" and=20
can't talk long.</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2></FONT> </DIV>
<DIV><FONT face=3DVerdana size=3D2></FONT> </DIV>
<DIV><FONT face=3DVerdana size=3D2>Doug Coulter, owner</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>C-Lab</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2><A=20
href=3D"mailto:c_lab@msn.com">c_lab@msn.com</A></FONT></DIV>
<DIV><FONT face=3DVerdana =
size=3D2>540-763-3753</FONT></DIV></BODY></HTML>
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