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AKhot.1
Associate III
September 1, 2023
Solved

FFT Nan Values; ADC DMA

I am getting nan values while computing the fft. It is mostly for fftOut[0][0]----- fftOut[0][512], after that there are not many nan values. What could be the reason?

Is it that because it running in debug mode and the DMA is on?

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Please help with this.

 

 

This topic has been closed for replies.
TDK
TDKBest answer
September 1, 2023

TDK_1-1693573944139.png

You are calling arm_rfft_fast_f32 multiple times (nChirp times) on the same data. That's no good here.

TDK_0-1693573907611.png

 

"If you feel a post has answered your question, please click ""Accept as Solution""."

2 replies

TDK
TDKBest answer
September 1, 2023

TDK_1-1693573944139.png

You are calling arm_rfft_fast_f32 multiple times (nChirp times) on the same data. That's no good here.

TDK_0-1693573907611.png

 

"If you feel a post has answered your question, please click ""Accept as Solution""."
AKhot.1
AKhot.1Author
Associate III
September 4, 2023

So, if I have a 2D array I need not to put the arm_rfft_fast_f32 function in for loop? I thought it would take ftt one by one along the row.