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Time-Delay Beamforming of Microphone ULA Array

This example shows how to perform wideband conventional time-delay beamforming with a microphone array of omnidirectional elements. Create an acoustic (pressure wave) chirp signal. The chirp signal has a bandwidth of 1 kHz and propagates at a speed of 340 m/s at ground level.

c = 340;
t = linspace(0,1,50e3)';
sig = chirp(t,0,1,1000);

Collect the acoustic chirp with a ten-element ULA. Use omnidirectional microphone elements spaced less than one-half the wavelength at the 50 kHz sampling frequency. The chirp is incident on the ULA with an angle of 60 azimuth and 0 elevation. Add random noise to the signal.

microphone = phased.OmnidirectionalMicrophoneElement(...
    'FrequencyRange',[20 20e3]);
array = phased.ULA('Element',microphone,'NumElements',10,...
collector = phased.WidebandCollector('Sensor',array,'SampleRate',5e4,...
sigang = [60;0];
rsig = collector(sig,sigang);
rsig = rsig + 0.1*randn(size(rsig));

Apply a wideband conventional time-delay beamformer to improve the SNR of the received signal.

beamformer = phased.TimeDelayBeamformer('SensorArray',array,...
y = beamformer(rsig);

title('Signal (real part) at the 5th element of the ULA')
title('Signal (real part) with time-delay beamforming')

Figure contains 2 axes objects. Axes object 1 with title Signal (real part) at the 5th element of the ULA contains an object of type line. Axes object 2 with title Signal (real part) with time-delay beamforming, xlabel Seconds contains an object of type line.