CHAPTER 13 – The Sine Wave and Wave Patterns

Publisher Summary This chapter discusses biological processes involving sine waves and wave patterns. In medicine, there are various biological processes that occur in a repetitive manner—for example, the ventilation of the lungs and the cardiac cycle. When these are monitored, a complex wave pattern of different types of simple wave forms—such as the sine wave, the sawtooth wave, and the square wave—are seen. Any waveform, no matter how complex, can be produced by selecting and adding together appropriate sine waves. The mathematical process of analyzing complex wave patterns into a series of simpler sine wave patterns is called Fourier analysis, and this concept helps in understanding the patterns of biological electrical signals. The two main points to note are that, firstly, any complex wave pattern may be analyzed into a large number of sine wave components and, secondly, wave patterns that have sharp spikes in them have high frequency components, while smooth and rounded wave patterns consist of a more limited range of frequencies. Wave motion is also present as variation in pressure in the case of sound waves and variation in the electric and magnetic fields in the case of electromagnetic radiation, such as light.