AnsweredAssumed Answered

CMSIS  arm_cfft_radix4_q15 library

Question asked by seungback jung on Mar 4, 2014
Latest reply on Nov 13, 2014 by Donald Bosley

Dear all.

I am now using the FFT Library on Kinetis K60 N512.




mycode .c



uint32_t fftSize  = 256;

uint32_t ifftFlag = 0;

uint32_t doBitReverse = 1;


arm_cfft_radix4_instance_q15 S;

arm_rfft_instance_q15 SQ;

arm_status status;


status = arm_cfft_radix4_init_q15( &S, fftSize, ifftFlag, doBitReverse); // Complex FFT initialisation

arm_cfft_radix4_q15(&S, ((q15_t *)data)); // Make CFFT in place



For comparison between the results obtained from Matlab FFT and CMSIS FFT library,

I want to know the exact FFT equation used inside CMSIS FFT library or the Matlab code on CMSIS FFT library.


The reason why I ask like this question is when I compared the results between both cases, I got the different result.

If there is anyone who know on my question, please let me know it.


Thank you in advance.