A sound is represented in a digital format by converting the sound into a sound wave. A microphone is used to convert the sound into an electrical signal A computer program then converts the analog signal to a digital signal. This process is known as pulse-code-modulation. The ability to convert an analogue sound into a digital format has revolutionised the music industry. The digital files are far smaller than the old analogue files. Digital files are far easier to distribute in the form of a downloadable file.