As you can guess, quadrature amplitude modulation is based on

The graph above is of some random signal, with an **amplitude**,
or strength, of 1. This signal has a **period** of *p*
(a **period** is the amount of time before a wave repeats itself).
We might let a signal with amplitude 1 represent a binary 0.

This is the same sound wave as above, because it has the same
period *p*. However, this signal has a higher amplitude of 2.
We might let a signal with amplitude 2 represent a binary 1.

This is what **amplitude modulation** looks like. Notice that
the period is the same for the entire signal, and that only the
amplitude varies.

Assuming amplitude 1 = binary 0, and amplitude 2 = binary 1, this signal would represent 0011010.