There is no break in the signal and the movement along the Sine wave never stops. The waves fluctuate a certain amount of times per unit of time, and this fluctuation over time is called the frequency. Frequency is measured in hertz, which means cycles per second. The more fluctuations, the higher the frequency. Higher frequency translates into higher notes.
Low frequency produces low, deep notes.
The signal also fluctuates in loudness. This loudness is called amplitude. Low volume is low amplitude. Digital Signals Digital signals are signals that are transferred as numbers. They are transferred using binary, so all that is on the recording medium are 1s and 0s.