Frequency is one of the two main sound features utilised in the normal detection of sound.
Measured in hertz (Hz) it refers to the number of cycles or repetitions per second of a waveform.

According to the frequency the sound is high or low pitch.

	A pure tone High pitch - 3000 Hz. A pure tone Low pitch - 300 Hz.
The human ear can hear a wide range of frequencies 20-20,000 Hz.