dsPIC 1024 or 2048 FFT?

Hello,

I'm programming a dsPIC33 that has 16384 bytes of RAM. I'm trying to figure 
out if I can do a 1024 or 2048 FFT with this device. The code examples and 
twiddle factors provided from Microchip only allow lengths up to 512. Does 
anyone know if longer length FFTs are possible on the dsPIC33?

Thanks,
Thomas Magma 

Thomas Magma wrote:

> Hello,
> 
> I'm programming a dsPIC33 that has 16384 bytes of RAM. I'm trying to figure 
> out if I can do a 1024 or 2048 FFT with this device. The code examples and 
> twiddle factors provided from Microchip only allow lengths up to 512. Does 
> anyone know if longer length FFTs are possible on the dsPIC33?

If you are not concerned about super efficiency or super accuracy, the 
FFT only requires 2 x data points of RAM plus small amount for the 
temporary variables. Hence the 2048 point FFT at 16 bits should fit into 
dsPIC33.


Vladimir Vassilevsky
DSP and Mixed Signal Design Consultant
http://www.abvolt.com

 > If you are not concerned about super efficiency or super accuracy, the
> FFT only requires 2 x data points of RAM plus small amount for the 
> temporary variables. Hence the 2048 point FFT at 16 bits should fit into 
> dsPIC33.

Any idea where I could find the twiddle factors for a 16-bit 2048 point FFT?

Thomas 

ok I'll bite. What is a twiddle factor?


"Thomas Magma" <somewhere@overtherainbow.com> wrote in message
news:S_Nlj.3839$lw.275@pd7urf1no...
> > If you are not concerned about super efficiency or super accuracy, the
> > FFT only requires 2 x data points of RAM plus small amount for the
> > temporary variables. Hence the 2048 point FFT at 16 bits should fit into
> > dsPIC33.
>
> Any idea where I could find the twiddle factors for a 16-bit 2048 point
FFT?
>
> Thomas
>
>