Shafik wrote:> Sorry for the wait Jerry, > > I want to be able to, in real time, generate an arbitrary tone > between 3000Hz and 4000Hz, accurate to within 50 Hz. "Real-time" in > this case is 1/8000th of a second (sampling rate is 8Khz). Im running > this on a 60MIP chip. > > The tone itself has to be clean, and that's why running through a table > of cosines won't cut it. > > --ShafikAh, but if you have enough memory -- you haven't said how much -- it can be as clean as you like. Does your chip do floating point? Jerry -- Engineering is the art of making what you want from things you can get. �����������������������������������������������������������������������
Arbitrary Digital Tone generation?
Started by ●February 21, 2005
Reply by ●February 22, 20052005-02-22
Reply by ●February 23, 20052005-02-23
Memory is limited (300-500 bytes), and I can't do floating point. The signal needs to be 'clean' enough to modulate voice (Im using the generated tone as an inversion frequency). --Shafik
Reply by ●February 23, 20052005-02-23
Shafik wrote:> Memory is limited (300-500 bytes), and I can't do floating point. > > The signal needs to be 'clean' enough to modulate voice (Im using the > generated tone as an inversion frequency). > > > --ShafikNow, for the first time, you've told me that the problem is hard. I'll think on it. Jerry -- Engineering is the art of making what you want from things you can get. �����������������������������������������������������������������������
Reply by ●February 23, 20052005-02-23
"Shafik" <shafik@u.arizona.edu> wrote in news:1109131338.940829.231840 @f14g2000cwb.googlegroups.com:> Memory is limited (300-500 bytes), and I can't do floating point. > > The signal needs to be 'clean' enough to modulate voice (Im using the > generated tone as an inversion frequency). > > > --Shafik >Generating a cosine wave is a very clean method. It will be as good as the precision of the DAC and the cosine table. Sigma Delta DACs are very good and often very inexpensive. I would consider the possibility of doing the modulation in a DSP. In this case, make sure that your cosine is very high precision. You may also want to consider a frequency that is a little more "prime" to 8000. This will tend to minimize spurs. -- Al Clark Danville Signal Processing, Inc. -------------------------------------------------------------------- Purveyors of Fine DSP Hardware and other Cool Stuff Available at http://www.danvillesignal.com
