Session 4 - Sampling Sound

This session explains how sound is converted from a continuous analogue sound that we hear in the real world and converts it into a digital format of 1s and 0s that can be used and played back by a computer. The session has a set of slides to read through and a worksheet.

1. Read slides 1 and 2 . This explains how sound is stored and why we use 1s and 0s to represent it. Go to slide 3 and consider the question posed at the start of the slide before reading the answer. This explains how we get sound into 1s and 0s and what we mean by sampling. Now read slides 4 and 5 to understand the terms sample rate and bit rate and how changing these affects the overall sound quality and file size.
2. Follow the instructions on slide 6. Work carefully through the tasks on the worksheet and refer to the slides to understand how to represent your sound waves on the grids provided for task 1 and task 2. Remember an analogue wave is continuous.
3. Task 2 requires you to show how you will sample the wave by drawing a rectangle to represent the wave on each column. Have the original wave also drawn on here so that you can see how close it matches.
4. Complete Task 3 on the worksheet. You need to read the values off the grid for each column for the samples. First create these in denary and then convert them to binary. How many bits have you got?
5. Finally, on Task 4 you need to redraw the sound wave using the binary values.
6. Go back to the slide and read about the frequency of sampling and Nyquist’s Theorem on slide 7.