【題組】36.
(A) When you arc closc to where the pebble fell, the waves ans clcarly in a circle, centeredon where the pebble fell.
(B) These are measured to ensure compliance with laws that govern acceptable soundemitted from a vehicle.
(C) Engineers can use scveral analysis tochniques to identify noise sources includingnear-field acoustic holography (NAH) and beamforming.
(D) Beamforming presents several challenges including simultaneously measuring a largenumber of microphone sensors: transmitting and saving this large amount of acquiredwaveform data, and being able to quickly process large data sets.