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% 2 microphone TDOA using CPS | |
% http://www.academia.edu/5280022/Direction_of_arrival_estimation_by_cross- | |
% power_spectrum_phase_analysis_using_prior_distributions_and_voice_activit | |
% y_detection_information | |
function [sample_delay, theta_deg]=tdoa(sig, chunk_size, Fs, dist) | |
% sig should be samples x 2, and a multiple of chunk_size | |
% chunk_size is the size of each window | |
% Fs is Fs | |
% dist is distance mics are apart in mm | |
v = 343.2 * 1000; % mm / s speed of sound | |
[samples, channels] = size(sig); | |
chunks = samples/chunk_size; | |
sample_delay = zeros(chunks, 1); | |
theta_deg = zeros(chunks, 1); | |
for i=0:chunks-1 | |
chunk_i = sig( (i*chunk_size)+1:(i+1)*chunk_size, 1); | |
chunk_j = sig( (i*chunk_size)+1:(i+1)*chunk_size, 2); | |
top = fft(chunk_i) .* conj(fft(chunk_j)); | |
bottom = abs(fft(chunk_i)) .* abs(fft(chunk_j)); | |
csp = ifft(top ./ bottom); | |
[y, idx] = max(csp); | |
theta = abs(asind( (idx * v) / (dist * Fs) )); | |
sample_delay(i+1, 1) = idx; | |
theta_deg(i+1, 1) = theta; | |
end |
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