fft beamforming - RF Cafe Forums
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Post subject: fft beamforming
Posted: Tue Apr 12, 2005 3:09 am
i'm a beginner in this area.
i just learned about
the basic algorithm of fft beamforming from internet.and
want to implement the algorithm by using matlab,but
i don't know how to start(ps,i'm also a new user
can anyone give me some sample
souce code, even segments are okay.
stuck in mud.
thanks in advance.
Post subject: Beamformer
Posted: Mon May 09, 2005 5:51 am
I give you a sample code for creating the filter
coefficients of a Delay and Sum beamformer. if you
have any question you can contact me on my email
Have a nice day.
c = 340; % m/s
nfft = 128; % nfft length
= -i*2*pi/c; % f will be variable
n_mic = 7;
mics = [ (-10*3:10:10*3)' zeros(7,1) ]/100;
= [-0.2 0.63]; % to be measured
fs = 22050; %
f = (0:nfft-1)*fs/nfft; %
W = zeros(n_mic,nfft);
w = zeros(n_mic,1);
r = zeros(n_mic,1);
u = zeros(n_mic,1);
bp = zeros(nfft,181);
bps = zeros(1,181);
% Filter Coef
k = 1:n_mic
r(k) = norm( source - mics(k,:));
index = 1;
d = exp(i_omega*p*r)./r;
W(:,index) = w;
for theta = theta_v
u(k) = norm(s-mics(k,:));
index = index + 1;
% here you can
plot the BP as a function of DoA for any frequency.
% Implementing the Beamforming
skiprate = nfft/2;
window = triang(nfft)';
num_samples = size(data,2); % data size
num_blocks = ceil((num_samples-nfft)/skiprate);
frame = 1:nfft;
data_frame = zeros(n_mic,nfft);
% frame of data ( from each mic)
= zeros(nfft,n_mic); % FFT of the frame
= zeros(1,nfft); % frame data (time)
for m = 1 :
data_frame = data(:,frame);
data_fft = fft(data_frame');
s = sum(conj(W).*data_fft');
S(frame) = S(frame) + real(ifft(s.*window));
frame = frame + skiprate;