12 Replies Latest reply on Oct 25, 2013 6:03 AM by user_200706552

    Simple DDS [State Variable, IIR]

    user_14586677

      Here is a DDS approach another poster turned me on to, very fascinating.

         

       

         

      Think State Variable, second order, 2 integrators + sign change = oscillator. Or think

         

      second order IIR with positive feedback.

         

       

         

      Runs just from C code, 80 uS ( 12.5 Khz ), 40 samples/sine.

         

       

         

      With optimization, conversion to fixed point, binary size elements, ASM vs C, or HW solution,

         

      should yield much higher freq.

         

       

         

      Add a timer to control code placed in ISR, eg.  sample period, or just use a delay function to control sample rate.

         

       

         

      Regards, Dana.