Noise Floor

Noise floor is the measure of the noise density, in dBm/Hz, or the noise power in a 1 Hz bandwidth.

Noise can be classified into several types, including the following:

  • Shot noise
  • Thermal noise
  • Flicker noise
  • Burst noise
  • Quantization noise
  • Avalanche noise

For example, in an audio system, the broadband noise level may be 5 µV. This means that broadband signal levels cannot be detected below this level. However, if the noise is broadband random noise, instead of consisting of sinusoidal components, you can use a narrow band filter to further investigate the noise.

Noise floor is normally specified as one or more of the following characteristics:

  • Broadband noise (referenced to full scale deflection)
  • Spurious free dynamic range
  • Noise power density (used to specify broadband random noise)