ECE420: Adaptive LMS Noise Cancellation System

Our project is to implement a noise cancellation system using Adaptive LMS Algorithm. However, it is hard to show noise cancellation on YouTube. So, we decide to demonstrate Adaptive LMS use a more visual way.

Adaptive LMS filter is basically a filter making another filter. Give an input and output, adaptive LMS filter can automatically estimate and update the filter coefficients.

We set up two microphones, one is close to speaker, another one is some distance apart. We play a constant noise cancellation, we can move the microphone apart from speaker some distance away. Then once the filter is converged (can be observed from scope), we hit stop and export the filter coefficients we had now to Matlab, thus we can how long it takes to get a spike. The position of spike is also the distance between two microphones. So another application of our system is use to detect distance between two objects.

Our LMS filter is implemented using assembly on a TI-55x DSP board.