Microphone array, literally, refers to the arrangement of microphones. That is to say, a system composed of a certain number of acoustic sensors (usually microphones) to sample and process the spatial characteristics of the sound field.
As early as the 1970s and 1980s, microphone arrays have been used in the research of speech signal processing. Since the 1990s, speech signal processing algorithms based on microphone arrays have gradually become a new research focus. In the "voice control age", the importance of this technology is particularly prominent.
The microphone array substantial signal coupling position. The start time of the receiving area. Voice signal processing has been applied since the 1970s and 1980s
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3 Practical problems that can be solved
In the frequency response, it is also possible to analyze the direction of the received voice signal source and its changes based on the application of beamforming in the time domain similar to that of the spatial filter. These analyses can display the intensity and angle of the voice signal in the form of a beam from the polar coordinate diagram.
Usually used in mobile phones (such as Apple iPhone, Samsung Galaxy series, etc.) and computers (such as Lenovo Y series, etc.). Using this technology, the difference between the phases of the sound waves received by the two microphones can be used to filter the sound waves, and the environmental background sound can be eliminated to the greatest extent, leaving only the required sound waves. For devices with this configuration in a noisy environment, there is no noise.
The microphone array is different from the antenna array
The voice signal is a wideband signal.
The indoor reverberation or multipath effect is significant.
Both environmental characteristics and signals are highly non-stationary.
The noise and the target speech signal may have the same spectral characteristics.
The number of sensors is usually limited.
Human hearing has an extremely wide dynamic range and is extremely sensitive to the weak tail of the channel impulse response. Therefore, the length of the filter model is very long.
Because of these problems, many existing algorithms have poor performance in solving some practical problems. Many microphone array processing algorithms are obtained after borrowing narrowband array processing algorithms or simply generalizing them. To put it simply, the microphone array needs to handle broadband signals.
Practical problems that can be solved
Go to reverb.
Single or multiple sound source localization.
Estimated number of sound sources.
Cocktail party effect.