Venkat,
To add on to this from Booshan's mail and Jeff's comments,
here are some points to consider.
You mentioned you are doing a 40 point FFT. Please note that any type of
fast convolution has some disadvantages.
They are as follows:
(i) Increased Memory locations on your DSP RAM to do the block
processing, example : Y(w) = H(w)X(w)
(ii) There is also inherent processing delay. You need to store the Frame
and make sure its full before you do the frequency domain multiplication as
compared to time domain convolution which is sample by sample.
With regards to computational savings as Booshan pointed out, with fast
convolution
its O(4*([3N/2 lg(base2)N + N)]) while normal time domain convolution will
use up 2N - 1 assuming equal length sequences of length N.
Fast Convolution is ONLY faster if the following inequality is
satisfied:
6Nlog(base2) N + 4N < N^2
In your case N@, please do the computation above and see if the equality is
satisfied. If not fast convolution is not for your end application as its not
going to help in terms of computational savings. However since N is a power of
2, you need to append zeroes and the nearest Nd.
Even for Fast Hartley there has to be an inequality to be satisfied before
its efficiencies that make it "Fast" are realized.
By the way are you from PSG Tech in Coimbatore? :) One of my good friends
is from there. Keep up the good work. Valka Valarka.
Hope this Helps.
Sincerely,
Shree Jaisimha
In God We Trust.
Jeff Brower <j...@signalogic.com> wrote:
Shree Jaisimha
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