DDS and the Electronic Music Box - April 2012
Posted: Wed Mar 21, 2012 5:06 pm
First, I very much enjoyed the article on DDS by Craig Lindlay.
I do have a question, mainly to make sure I'm understanding DDS process.
If, as in the example, M is set to 295,279,002, and the sample frequency is as given at 32Khz, and also as given, I have a wave table with 256 entries (2^8), and I truncate the 32 N bit accumulator word to an address word of 8 bits to address the wave table, then at 2.2Khz output, isn't my increment into the wave taable going to be about 17.something (incrementing the address by 17.something), and at 256/360 degrees, isn't that going to give me a sine wave increment of about 24 degrees for each increment into the wave table?
In other words, aren't I incrementing an actual wave form by about 24 degrees each time?
That doesn't seem to be too accurate, so what am I missing?
Thanks!
I do have a question, mainly to make sure I'm understanding DDS process.
If, as in the example, M is set to 295,279,002, and the sample frequency is as given at 32Khz, and also as given, I have a wave table with 256 entries (2^8), and I truncate the 32 N bit accumulator word to an address word of 8 bits to address the wave table, then at 2.2Khz output, isn't my increment into the wave taable going to be about 17.something (incrementing the address by 17.something), and at 256/360 degrees, isn't that going to give me a sine wave increment of about 24 degrees for each increment into the wave table?
In other words, aren't I incrementing an actual wave form by about 24 degrees each time?
That doesn't seem to be too accurate, so what am I missing?
Thanks!