Tip:
Highlight text to annotate it
X
ActiveNoiseReduction@gmail.com
Active noise reduction is a way to decrease level of noise
by adding sound wave of noise and eliminating signal
The research of ANR effect is carried on this model
Modeling is held in the acoustic tube with the use of two loudspeakers
The first loudspeaker acts as noise source,
the second - as cancelling loudspeaker
Algorithm development was held on dev-board with Digital Signal Processor from Texas Instruments
Sinusoidal wave for noise source loudspeaker is generated by cellphone application
Soundtrack is recorded by the dictaphone
Real-time signal spectrum can be watched on the screen
Let's begin the demonstration
Noise source loudspeaker produces a sinusoidal signal with 250Hz frequency
One can see the appearance of harmonic corresponded to 250 Hz frequency
and incidental harmonics on the screen
Let's turn the ANR system on
One can see the fall of harmonic corresponded to 250 Hz frequency
from 10 dB to -40 dB
Let's turn the ANR system off
Harmonic has come back to the original value
Active noise reduction has an ability to be applied
in industry, medicine, automobiles, office and consumers spheres and other areas
ActiveNoiseReduction@gmail.com