Realtime FFT (No GUI)


#1

Hi all,

I am new to GNURadio. I need to do realtime FFT (GUI is not required).
I need to feed this FFT to other components of the system so I ned
simple FFT values of the signal. I tried hacking the fftsink2.py and
was able to get the values but the problem is that the rate of data is
very less. I am getting 15-16 FFTs in a second. This is too less.

Can you suggest me a way to improve this?

Thanks.

Mayank


#2

On Mon, Nov 10, 2008 at 04:02:12PM -0500, Mayank G. wrote:

Hi all,

I am new to GNURadio. I need to do realtime FFT (GUI is not required). I
need to feed this FFT to other components of the system so I ned simple
FFT values of the signal. I tried hacking the fftsink2.py and was able to
get the values but the problem is that the rate of data is very less. I
am getting 15-16 FFTs in a second. This is too less.

Can you suggest me a way to improve this?

Just use the gr.fft_vcc block.

Eric


#3

On Mon, Nov 10, 2008 at 4:08 PM, Eric B. removed_email_address@domain.invalid wrote:

Just use the gr.fft_vcc block.

Eric

On a related note, I am curious if anyone has looked into using djbfft
as opposed to FFTW? I know it hasn’t been updated in a while, but it
appears to be extremely fast:

http://cr.yp.to/djbfft.html

Just wondering.

Brian


#4

Hi,

I tried using that. But I think it returns some sptr datatype and I am
unsure how to use it and get all the data points out of it.

Can you guide me through that?

Thanks.


#5

On Mon, Nov 10, 2008 at 04:24:44PM -0500, Mayank G. wrote:

Hi,

I tried using that. But I think it returns some sptr datatype and I am
unsure how to use it and get all the data points out of it.

Can you guide me through that?

Sorry, no.

Eric


#6

Thanks for the response.

But, how can I interface the USRP and FFTW or DJTFFT?