Cost-effective, Analogue “Noise Cancellation Headphones” designed using Discrete Components only.

Class project for EE-340 DEVICES & ELECTRONICS (Dr. Nauman Zaffar), Fall 2011.

Collaborated with: Ovais Bin Usman, Umar Mustafa, Syed Bilal Ali

We implemented active noise cancellation on simple headphones, using BJT Amplifiers and RC Filters. Our design was cost-effective and portable.

Abstract: Sound waves can interfere with each other to result in an attenuated wave whose amplitude depends on the respective phases of the interfering waves. The phenomenon of destructive interference occurs when the interfering waves are 180 degrees out-of-phase and results in a wave with zero amplitude.

This was the basic principle on which we designed the circuits to cancel undesired noise. The main steps involved: catching the surrounding noise and converting it to an electronic signal using microphones and filters, amplifying and inverting the signal, adding the inverted signal to the original signal (music etc.) and converting the signal back to sound through the headphones. The idea was that the inverted signal will destructively interfere with the surrounding undesired noise and cancel it.

Project Report