Sound Files:

The sound signal is an illustration of a continuous signal which is sampled to result in a discrete signal. In this situation, sound waves traveling through the air are recorded as a set of measurements which can then be used to reconstruct the original sound signal as closely as possible. The sampling frequency or sampling rate is the number of samples taken per time unit, for illustration per second.

The Sound signals are generally measured in Hertz (Hz).

In MATLAB, the discrete sound signal is presented by a vector, and the frequency is measured in Hertz. The MATLAB has numerous MAT-files which store, for various sounds, the signal vector in a variable y and the frequency in variable Fs. These MAT-files involve gong, chirp, laughter, train, splat, and handel. There is a built-in function, sound, which will send a sound signal to an output device like speakers. The function call

>> sound(y,Fs)

will play the sound presented by the vector y at the frequency Fs. For illustration, to hear the gong, load variables from the MAT-file and then play the sound by using the sound function:

>> load gong

>> sound(y,Fs)

The Sound is really a wave; the amplitudes are what are stored in the sound signal variable y. These are assumed to be in the range from -1 to 1. The plot function is used to show the data.