Example: Square wave

• The square wave signal shown below is clearly not sinusoidal.
• However, we will see that it can be represented (approximated) by a sum of sines.
• The frequencies of the sines in the approximation are multiples of the inverse of the period of the square wave.
• In this case the period of the square wave is 1 second.
• Hence the so-called fundamental frequency of this signal is 1/1 sec=1 Hz.

  

Figure 4.1: Square Wave