need FFT Overlap

Hello All,

    After Block based FFT an overlap is done between blocks to remove
block artifacts. But my query is if i perform FFT  on 512 block of
data, i get 512 freq samples output. If i continue this for 10 blocks i
will get 512 * 10 samples in freq samples then how can perform overlab
of the block? if i do i will be loosing data also and aliasing will be
thr.

   Can any one explain how to perform overlap of block after FFT? and
also other advantages of it.

Rgds
-Prasad

Prasad wrote:

> Hello All,
>
>     After Block based FFT an overlap is done between blocks to remove
> block artifacts. But my query is if i perform FFT  on 512 block of
> data, i get 512 freq samples output. If i continue this for 10 blocks i
> will get 512 * 10 samples in freq samples then how can perform overlab
> of the block? if i do i will be loosing data also and aliasing will be
> thr.
>
>    Can any one explain how to perform overlap of block after FFT? and
> also other advantages of it.

We have done this a couple of times, for example here (also view the
follow up messages):

http://groups.google.ch/group/comp.dsp/msg/7585d35fd4ba3693

Online documentation of overlap-add and -save methods can be viewed,
for example, here:

http://www.dspguide.com

Regards,
Andor