cmsis dsp library: fft length

[teijo]

Posted on November 24, 2014 at 13:22

Hi,

I

f i

understand correct

ly

using fft functions like 

http://mazsola.iit.uni-miskolc.hu/DATA/segedletek/arm/cmsis/CMSIS/Documentation/DSP/html/group___r_f_f_t___r_i_f_f_t.html#ga3df1766d230532bc068fc4ed69d0fcdc

, maxim

um fft length are 204

8. Is

t

here

any possibility to use longer

dat

a lengths

?

br

Teijo

[frankmeyer9]

Posted on November 24, 2014 at 14:44

I

f i

understand correct

ly

using fft functions like 

http://mazsola.iit.uni-miskolc.hu/DATA/segedletek/arm/cmsis/CMSIS/Documentation/DSP/html/group___r_f_f_t___r_i_f_f_t.html#ga3df1766d230532bc068fc4ed69d0fcdc

, maxim

um fft length are 204

8

 

IMHO it were either code size or runtime considerations that prompted ARM to limit the input size to 2^11.

 

Is

t

here

any possibility to use longer

dat

a lengths

?

You could either try to extend the DSP lib code, or find another suitable implementation.

There are plenty of others around which might better suit your needs, like implementations for arbitrary input length (like bluestein's fft), or to calculate just one or a few points of the spectre.