You wouldn't have a link for the Intel libraries? At 05:47 PM 1/28/2006, you wrote:
>Rud, > > a very good (and _free_) book is available online at > http://www.dspguide.com >It is at an introductory level, as you seem to need. > >A good discussion group is comp.dsp on usenet, though not always the >gurus there >are so willing to answer to basic questions. But trying costs nothing... > >About libraries to compute FFTs, what I use in my programs is the Intel >Signal Processing Library, which is free for non commercial applications. >It is very fast, being coded in hand-optimized assembler language. >Otherwise another good library is FFTW ( http://www.fftw.org ) > >73 Alberto I2PHD >---------------------------------- > > > I want to experiment with digital protocols in ham radio by starting > > with the PC soundcard. I understand some of the basics like filters > > and FFT. I even have some of them working in code (C++). > > > > I do not know how to proceed from the basics into demodulating an > > audio signal into bits. > > > > For instance, I am playing with the VHF packet protocol which use 1200 > > and 2200 hz signalling. I enter the samples for a single 1200 hz cycle > > into the FFT array. The FFT shows a peak at around 1000 hz. The FFT > > array is 2048 samples long filled with 0s except for the 1 cycle of > > 1200 hz which is 40 samples at the rate of 48000 samples per second. > > If I put 4 cycles in the FFT array I get 1195 hz which is correct. > > Hanning or Hamming Windows do not help. > > > > I have looked at some of the available source but am missing the > > insight I need for proceeding further. Any suggestions on how to > > proceed further? Any suggestions on books or web sites that address > > communications DSP at this level? How about an email reflector where I > > can ask questions of DSP gurus? > > > > -73- > > Rud K5RUD > > ARES AEC > > Montgomery County, TX > > > > > > > > ------------------------------------------------------------------------ > > YAHOO! GROUPS LINKS > > > > * Visit your group "soft_radio > > <http://groups.yahoo.com/group/soft_radio>" on the web. > > > > * To unsubscribe from this group, send an email to: > > [EMAIL PROTECTED] > > <mailto:[EMAIL PROTECTED]> > > > > * Your use of Yahoo! Groups is subject to the Yahoo! Terms of > > Service <http://docs.yahoo.com/info/terms/>. > > > > > > ------------------------------------------------------------------------ > > > > . > > > > >Yahoo! Groups Links > > > > > > > > > >-- >No virus found in this incoming message. >Checked by AVG Free Edition. >Version: 7.1.375 / Virus Database: 267.14.23/243 - Release Date: 1/27/2006 > > > > >-- >No virus found in this incoming message. >Checked by AVG Anti-Virus. >Version: 7.1.375 / Virus Database: 267.14.23/243 - Release Date: 1/27/2006 Cecil Bayona KD5NWA www.qrpradio.com "I fail to see why doing the same thing over and over and getting the same results every time is insanity: I've almost proved it isn't; only a few more tests now and I'm sure results will differ this time ... " -- No virus found in this outgoing message. Checked by AVG Anti-Virus. Version: 7.1.375 / Virus Database: 267.14.23/243 - Release Date: 1/27/2006 Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/soft_radio/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
