NPTEL : NOC:Basics of Noise and Its Measurements (Mechanical Engineering)

Co-ordinators : Prof. Nachiketa Tiwari


Lecture 1 - Introduction

Lecture 2 - Vibration versus Waves

Lecture 3 - Nature of Sound

Lecture 4 - The Decibel Scale

Lecture 5 - Some Key Terms

Lecture 6 - Adding Decibels

Lecture 7 - Modeling Sound Propagation

Lecture 8 - The Momentum Equation

Lecture 9 - The Continuity Equation and The Gas Law

Lecture 10 - 1-D Wave Equation

Lecture 11 - General Solution for 1-D Wave Equation

Lecture 12 - Complex Time Signal and Transfer Functions

Lecture 13 - Transmission line equations

Lecture 14 - Planar Waves in Closed Tubes

Lecture 15 - Planar Waves in 1-D Open Tubes

Lecture 16 - A Semi-Infinite Tube and Overall Summary

Lecture 17 - 1-D Tubes with Imperfect Terminations

Lecture 18 - Measuring Impedance Through Kundt’s Apparatus

Lecture 19 - Classification of Microphones

Lecture 20 - Classification of Microphones - Continuation

Lecture 21 - Classification of Microphones by Application

Lecture 22 - Microphone Sensitivity

Lecture 23 - Microphone Sensitivity- Continuation

Lecture 24 - Selecting the Right Microphone

Lecture 25 - Fourier Series Expansion

Lecture 26 - Fourier Series Expansion - Continuation

Lecture 27 - Fourier Integral

Lecture 28 - Fourier Integral - Continuation

Lecture 29 - Fourier Transform

Lecture 30 - Fourier Transform - Continuation

Lecture 31 - Discrete Fourier Transform (DFT)

Lecture 32 - Discrete Fourier Transform (DFT) - Continuation

Lecture 33 - DFT - Calculating Frequencies and Padding

Lecture 34 - DFT - Influence of Duration and Sampling frequency on resolution

Lecture 35 - FFT and Inverse FFT

Lecture 36 - Considerations while deciding instrumentation

Lecture 37 - Considerations while selecting instruments for noise measurements

Lecture 38 - Measuring impedance through two microphone method

Lecture 39 - Designing an impedance measurement tube

Lecture 40 - Octave band analysis

Lecture 41 - Calculating results in octave bands

Lecture 42 - Weighting

Lecture 43 - Short time Fourier transforms (STFT)

Lecture 44 - Spectrograms

Lecture 45 - Reverberation time

Lecture 46 - Anechoic rooms

Lecture 47 - STC, NRC and sound attenuation

Lecture 48 - Reverberant rooms