Because of the high maintenance needed to monitor and filter spammers from the RF Cafe Forums, I decided that it would
be best to just archive the pages to make all the good information posted in the past available for review. It is unfortunate
that the scumbags of the world ruin an otherwise useful venue for people wanting to exchanged useful ideas and views.
It seems that the more formal social media like Facebook pretty much dominate this kind of venue anymore anyway, so if
you would like to post something on RF Cafe's
page, please do.
Below are all of the forum threads, including all
the responses to the original posts.
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;