FFT Fixed Point in Matlab Code

Folks,

Is there any free source code for FFT Fixed Point in Matlab Code ?

Thanks.

Rgds,

Berry

in article 4225c8ca$0$29279$14726298@news.sunsite.dk, Mas Bas at
buzzberry@gmail.com wrote on 03/02/2005 09:08:

> 
> Is there any free source code for FFT Fixed Point in Matlab Code ?
> 

i would like a copy, too.  i have been thinking of writing the same for
simulation for both educational reasons and a possible project in the
future.

it need only be the standard Cooley-Tukey radix-2 .

this is why i had been thinking a lot about FFT quantization, lately, as in
the other thread.

-- 

r b-j                  rbj@audioimagination.com

"Imagination is more important than knowledge."

I have written Radix-2 FFT fixed point code in C. I think I should be
able to convert it into Matlab in a relatively short time. I will post
it here once it is ready.

Btw, I have three implementations of the radix-2 decimation in
frequency FFT algorithm.

(a) not-inplace and recursive
(b) inplace and recursive
(c) inplace and non-recursive

I needed (c) for my application. But, it was easy for me to start with
(a) and step towards (c). I tested my code against matlabs' fft
function for various test cases and it seems to be bug free.

Since what you need is a matlab implementation, it makes more sense to
implement a fourth version that is not-inplace and non-recursive. Let
me know if you think otherwise. I will post it as soon as I am done.
Most likely during this weekend.

Kal wrote:
> I have written Radix-2 FFT fixed point code in C. I think I should be
> able to convert it into Matlab in a relatively short time. I will
post
> it here once it is ready.
>
> Btw, I have three implementations of the radix-2 decimation in
> frequency FFT algorithm.
>
> (a) not-inplace and recursive
> (b) inplace and recursive
> (c) inplace and non-recursive
>
> I needed (c) for my application. But, it was easy for me to start
with
> (a) and step towards (c). I tested my code against matlabs' fft
> function for various test cases and it seems to be bug free.
>
> Since what you need is a matlab implementation, it makes more sense
to
> implement a fourth version that is not-inplace and non-recursive. Let
> me know if you think otherwise. I will post it as soon as I am done.
> Most likely during this weekend.

Sound interesting!

Will your FFT package require the Fixed Point Toolbox?

Will it allow a 40 bit accumulator and 16 bit data & coefficients?

You might be interested to compare your package to Mark Borgerding's
Kiss FFT at http://sourceforge.net/projects/kissfft/

John

Thanks Kal, we look forward to your FFT.

Cheers,
Berry,-

Kal wrote:
--deleted---
> Since what you need is a matlab implementation, it makes more sense to
> implement a fourth version that is not-inplace and non-recursive. Let
> me know if you think otherwise. I will post it as soon as I am done.
> Most likely during this weekend.
> 

john wrote:
>
> Will your FFT package require the Fixed Point Toolbox?
>
> Will it allow a 40 bit accumulator and 16 bit data & coefficients?

Thanks for asking all the right questions.

I do not have the fixed point tb. I was thinking of using the interger
types like INT16,32. That way the users dont need to have the fp-tb.

I was thinking of 16 bit data + coefficients and a large enough
accumulator that will avoid any over/under flows.

>
> You might be interested to compare your package to Mark Borgerding's
> Kiss FFT at http://sourceforge.net/projects/kissfft/

Looks interesting. I am yet to look at the source code though.

Later,
-Kalyan

Hi Berry,

Attached please find fixed-point FFT implementations in both M and C.

In the M implementation, to declare variables as fixed-point (as they are in
fft_example.m), the Fixed-Point Toolbox is required.  The other M-files will
work as-is with either floating-point or fixed-point input.

The C implementation is enclosed in a mex-file (so it can be called from
MATLAB). The C mex-file has int16 input and output, and int32 accumulator.

The accumulator and data can be set to any word length in the M fixed-point
object fi.

For an example of usage, run fft_example.m in MATLAB.

This was the main example used in the January 27th "Fixed-Point Programming
in MATLAB" webinar.  The recording of it has not been posted yet, but when
it is it will be here:
http://www.mathworks.com/products/fixed/demos.html

Let me know if the attachments don't come through, and I'll post them to
MATLAB Central.

Best wishes,
Tom Bryan
The MathWorks, Inc.

"Mas Bas" <buzzberry@gmail.com> wrote in message
news:4225c8ca$0$29279$14726298@news.sunsite.dk...
> Folks,
>
> Is there any free source code for FFT Fixed Point in Matlab Code ?
>
> Thanks.
>
> Rgds,
>
> Berry

Tom Bryan wrote:
> Hi Berry,
>
> Attached please find fixed-point FFT implementations in both M and C.
>
> In the M implementation, to declare variables as fixed-point (as they
are in
> fft_example.m), the Fixed-Point Toolbox is required.  The other
M-files will
> work as-is with either floating-point or fixed-point input.
>
> The C implementation is enclosed in a mex-file (so it can be called
from
> MATLAB). The C mex-file has int16 input and output, and int32
accumulator.
>
> The accumulator and data can be set to any word length in the M
fixed-point
> object fi.
>
> For an example of usage, run fft_example.m in MATLAB.
>
> This was the main example used in the January 27th "Fixed-Point
Programming
> in MATLAB" webinar.  The recording of it has not been posted yet, but
when
> it is it will be here:
> http://www.mathworks.com/products/fixed/demos.html
>
> Let me know if the attachments don't come through, and I'll post them
to
> MATLAB Central.
>
> Best wishes,
> Tom Bryan
> The MathWorks, Inc.
>
> "Mas Bas" <buzzberry@gmail.com> wrote in message
> news:4225c8ca$0$29279$14726298@news.sunsite.dk...
> > Folks,
> >
> > Is there any free source code for FFT Fixed Point in Matlab Code ?
> >
> > Thanks.
> >
> > Rgds,
> >
> > Berry

Is this code limited to power of two FFTs?

John

Tom,

Where are the attachments? Please upload to MATLAB Central, and tell us its 
final location.

Cheers,

-- 
------------------------------
Jaime Andr�s Aranguren Cardona
jaac@sanjaac.com
SanJaaC Electronics
Soluciones en DSP
www.sanjaac.com


"Tom Bryan" <tbryan@mathworks.com> escribi&#4294967295; en el mensaje 
news:d0a1im$g2a$2@fred.mathworks.com...
> Hi Berry,
>
> Attached please find fixed-point FFT implementations in both M and C.
>
> In the M implementation, to declare variables as fixed-point (as they are 
> in
> fft_example.m), the Fixed-Point Toolbox is required.  The other M-files 
> will
> work as-is with either floating-point or fixed-point input.
>
> The C implementation is enclosed in a mex-file (so it can be called from
> MATLAB). The C mex-file has int16 input and output, and int32 accumulator.
>
> The accumulator and data can be set to any word length in the M 
> fixed-point
> object fi.
>
> For an example of usage, run fft_example.m in MATLAB.
>
> This was the main example used in the January 27th "Fixed-Point 
> Programming
> in MATLAB" webinar.  The recording of it has not been posted yet, but when
> it is it will be here:
> http://www.mathworks.com/products/fixed/demos.html
>
> Let me know if the attachments don't come through, and I'll post them to
> MATLAB Central.
>
> Best wishes,
> Tom Bryan
> The MathWorks, Inc.