Home > Conscious > Chapter 4 > 4.1. Introduction to Oscillations



Figure 4-2. A simple pendulum. [Source: Wikipedia]

Oscillations are also quite common in the physical world, such as the movement of a pendulum. An ideal pendulum contains a bob connected to a pivot by a massless string (Figure 4-2). If initially the pendulum is displaced sideways from its equilibrium position, after released, the pendulum will swing back and forth around the equilibrium position (Figure 4-3).


Figure 4-3. The oscillation of a pendulum around the equilibrium position.

An oscillation system has three main physical parameters: frequency, amplitude and phase.

  • Frequency is the inverse of the period. Its unit is hertz (Hz). 1 Hz = 1/second.
  • Amplitude is the maximum displacement.
  • Phase refers to a time point in an oscillation cycle. If two oscillation systems are "in phase", they will arrive at the oscillation peak simultaneously. In this case, the two systems are "synchronized".

The neural oscillation is quite similar to the pendulum oscillation, both having three main physical properties. However, in neural oscillations, the waveform is composed of nerve impulses. An example is illustrated in Figure 4-4, which also compare the difference between synchronization and non-synchronization.


Figure 4-4. Neural oscillations. Oscillation A is synchronized with oscillation B because both of them arrive at the peak simultaneously. They are not synchronized with oscillation C.