Applet is designed to show user the basic idea behind time division multiplexing. Several signals (in this case, sound signals) can be transmitted over a single line by chopping them into smaller parts time-wise, and sending the parts of each sound signal in sequence. Thus you get a portion of each sound signal at a given period of time. With the right hardware at the receiving end, the signals can be extracted into their original forms.
To try this
simulation:
Left-click the buttons to play the voice sample, the music sample, or both multiplexed, respectively. Move the "Adjust Period" slider left and right to turn the period down or up, respectively.
What's Going On?
We are multiplexing sound!
Two sources of sound are being alternately played and sent to a speaker.
When you click the VOICE button, you are listening to the VOICE channel.
When you click the MUSIC button, you are listening to the MUSIC channel.
When you click the BOTH button, an electronic switch alternates between the two channels.
As you move the slider, the chopping frequency gets faster, or slower.
There's More!
In the data communications industry, this technique is known as "time division multiplexing". If you have a number of audio signals that you would like to send over a wire at the same time, you can use multiplexing! On one end of the wire, each channel of information is chopped and given a short period of time when its information is sent. At the other end of the wire, a chopper that is synchronized with each channel routes the information so you don't mix the channels and hear everything simultaneously. Multiplexing permits the efficient use of cables and fiber optics. The more signals that can be multiplexed, the fewer lines that have to be strung. In telephone communications, about 25,000 calls can be multiplexed on a single strand of optical fiber!
