Digital square wave signals are actually composites of multiple analog sine waves. In fact, many different types of waveforms (such as square waves, sawtooth waves, etc.) can be created by combining various forms of analog sine waves. (There is an area of mathematics called Fourier Analysis which examines such concepts.) The more analog sine waves that you add together, the closer the waveform approaches the intended form. To examine this, locate a webpage that allows you to interactively combine analog waveforms. One such page is at www.falstad.com/fourier. You can find many others by searching for fourier java applet. Notice how the square wave is combined of multiple sine waves. The first sine wave has a relatively slow frequency with a relatively high amplitude. The second sine wave has a higher frequency but a lower amplitude. (You can note each of these sine waves in the falstad site by moving the cursor over the sine component in the middle graph.)

Part A. Questions: In your opinion, how many sine components are necessary to create a square wave that is square?

What happens if you increase the amplitude of a component?

What happens if you increase the frequency of a component?