Good evening folks!
I came across something interesting in my trig book today in class, and it has intrigued me. Although, it may be something that everyone already knows about--except me.
Anyway, a math problem explains of an ANC system (Active Noise Control) where a mic picks up the sound, and is "processed electronically" to produce the same frequency and amplitude, but out of phase with the original. Then the signal is output through a speaker. The two waves (original and out of phase) collide to result in destructive interference. Thus, the noise is reduced.
Okay, I have a couple questions regarding this:
1. Do you folks know what kind of circuit this would entail? My first thought is to use an op amp.
2. This may be a little off the wall question but--You have the two waves out of phase from each other (I'm assuming 180 degrees out of phase???) and they collide to form destructive interference. So the waves are basically mauling each other. How exactly does this reduce the noise? My guess is that the interference causes the wavelenghts to decrease, thus the waves don't travel as far as they could. So an observer would interpret this as a reduction of noise, because not as many waves are reaching the observer (or the amplitudes are smaller). Am I correct?
This is pretty facinating to me. Does anyone know of any circuits, or an idea of how to go about creating something like this? I'd like to mess around with it, try different phase angles, amplitudes, wavelengths etc.
Thanks for reading, and taking the time to assist! Have a great one!