We show an approach to beamforming an acoustic source using a circular microphone topology. Consider the circular array illustrated in Figure 1 below and suppose a beamforming solution is desired.
Figure 1: Circular microphone array topology for microphones, .
Define the angle of arrival to be the impinging angle at microphone as , using the line joining microphones and as reference. Then by averaging the received signals at all eight microphones, it can be easily shown to that;
Here, is the delay between microphones and , the effective “sum filter”. can be synthesized as:
Suppose we have the angle of arrival, any beamforming algorithm together with filter can be deployed to reduce the noise considerably.
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