problems with fft routines in the dsplib of the dsk 5402

Started by radato1 June 3, 2002

i am implementing a simple program on the dsk 5402, which involves a fourier
Reading the application notes i have found out that there are some functions in
the dsplib
that do the hard work ('rfft256' and 'cbrev' for example).

When i have tested them and compared the results with the matlab outputs, i have
found out
that the results are WRONG: the real part is quite the same (differences of 2-3
can be
explained by the rounding error) but in the imaginary part, there is a block of
indexes in
the middle of the output buffer that are completely wrong (while the first
indexes, and the
last ones obviously, are o.k.). I found that in any length of the fft there is a
block in
the middle of the imaginary part which is wrong, and its size increases as the
fft length
goes larger.

i must emphasize that i have been careful in the alignment needed, and i used
cbrev as
specified in the notes.

Did any one met the same problems ?
Where can i find any updated versions of the dsplib ?

Raffaele DaTo