3.2 Signal Parameters

A signal has three main parameters which are:

		Amplitude,
		Frequency and
		Phase.

A signal's amplitude represents the strength of the signal over time.

The peak amplitude (A) of the signal is the maximum strength of the signal over time.

The signal's frequency (ƒ) represents the rate at which the signal repeats.

		The frequency is measured by the number of cycles repeated per second or Hertz (Hz).
		The signal's period (T) is a related parameter to frequency which represents the duration of one cycle,
		More formally: T = 1/ƒ.

3.2 Signal Parameters

Phase is another signal property which represents the fraction of a signal's period that has elapsed relative to a reference point.

A phase shift of a whole period represents a 360 degrees = 2Π radians.

The wavelength of a signal λ is the distance between two points of corresponding phase of two consecutive cycles.

The signal wavelength is related to the signal period as follows: λ = νT where ν is the signal velocity.

A signal is usually composed of many frequencies. Figure 3.8 shows how a signal is composed of two signals with different frequencies.

Figures 3.5, 3.6 and 3.7 illustrate the concepts of signal amplitude, frequency and phase.

3.2 Signal Parameters

Figure 3.5: An Example of Two signals with Different Peak Amplitudes and the Same Frequency and Phase.

3.2 Signal Parameters

Figure 3.6: An Example of Two Signals with Different Frequencies and the Same Peak Amplitude and Phase.

3.2 Signal Parameters

Figure 3.7: An Example of Two Signals with Different Phases and the Same Peak Amplitude and Frequency.

3.2 Signal Parameters

Figure 3.8: Signal 3 Composed of Signal 1 and Signal 2 with Two Frequencies ƒ and 3ƒ