ABSTRACT
A sound is a pressure that varies over time. Represented in electrical form, it is voltage or current that varies over time. This means that every sound – regardless of how many frequencies it might contain – can be described by a signal’s variation in time or its waveform. Complex tones are periodic signals that consist of a fundamental frequency with associated harmonic overtones. These signals are, among other things, characteristic of musical instruments. Real noise signals such as traffic noise or ventilation noise can also contain audible tones in addition to broadband noise. The phase component of a signal expresses how much a sinewave is delayed compared to a reference sinewave with the same frequency. Noise signals can also be a part of the sound of musical instruments, such as the “resin sound” of the strings or the air noise of various wind instruments.
