Sunday, August 24, 2014

Corrections to DDS code

Many thanks to my friend Eldon, WA0UWH who pointed out the fact that my 0-255 amplitude table in my previous post has some 256 values in it.  Oh sigh...  I neglected to take into account that the range of sine values is -1 to +1 inclusive.  I added a generic mapping function to handle the mapping correctly.  I have updated my previous post with the changes.  This also fixed the gliches seen in my integrated output.  See the last scope trace screen shot.  I have updated this photograph as well, so all evidence of temporary insanity has been removed...

Thanks Eldon!
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1 comment:

  1. Anonymous01 March, 2015 11:46

    I loaded your code with my own generated tables of different sizes and ran into the same glitch. Should have read this correction first.
    My hack of your code is at: https://db.tt/UDpYbPpn I fluffed it up a bit to make a demo for a STEM fair.
    Thanks for the head start on tone generation code for my keyer project.

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