embedded - how much THD do I expect on a 32 bits float sine waveform? -

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i'm using stm32f411 uc generate sine wave using cmsis dsp libary sine waveform used feed audiocodec i2s inteface notice harmonics on analog output f codec thiking on how thd waveform have thank

edit sine wave form 1 on cmsis dsp library https://github.com/mikeferguson/stm32/blob/master/libraries/cmsis/dsp_lib/fastmathfunctions/arm_sin_f32.c need harmonics added digital sine waveform i'm thinking on create array of sine values created function , analize on matlab

how quantization noise , thd given tone generator adds, depends entirely on it's implementation details , not straight forward derive. suggest, analyzing output in matlab or similar 1 way it. alternatively, if care whether or not generator or analog parts blamed, easier approach might generate simple sine fraction of sample frequency. can done without fancy cmsis library pre-calculating array of e.g 8 samples in matlab sine frequency of fs/8. thd measurements again. if thd still big, cmsis generator not blame.

regards klaus


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