Overlap–add method: Difference between revisions

Revision as of 04:37, 15 January 2020

Revision as of 06:13, 15 January 2020

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==Pseudocode==

AThe following is a [[pseudocode]] of the algorithm is the following:

<font color=green>('''AlgorithmOverlap-add 1''' (''OAalgorithm for linear convolution'')</font>

h = FIR_impulse_response

Evaluate the best value of N and L (L > 0, N = M + L - 1 nearest to power of 2).

Nx M = length(xh);

Nx = length(x)

H N = FFT(h, N) 4 × M <span style="color:green;">(''zero-paddedor a nearby FFT''power-of-2)</span>

i = 1

step_size = N - y = zeros(1, M + Nx - 1)

H = DFT(h, N)

'''while''' i <= Nx <span style="color:green;">(''Nx: the last index of x[n]'')</span>

position = 0

il = min(i + L - 1, Nx)

y(1 : Nx + M-1) = 0

yt = IFFT( FFT(x(i:il), N) * H, N)

k = min(i + N - 1, M + Nx - 1)

'''while''' position + step_size ≤ Nx

y(i:k) = y(i:k) + yt(1:k - i + 1) <span style="color:green;">(''add the overlapped output blocks'')</span>

y(position+(1:N)) = y(position+(1:N)) + IDFT(DFT(x(position+(1:step_size)), N) × H)

i = i + L

position = position + step_size

'''end'''

== Cost of the overlap-add method ==