Noise-Cancellation
The PLR Algorithm
The Power-Level Ratio (PLR) algorithm was originally designed for two-microphone noise-reduction in cell phones [3]. One microphone, the primary, receives mostly speech. A second reference microphone receives mostly background noise. However, simply subtracting the reference from the primary is ineffective, increasing the noise rather than cancelling it [4]. Therefore, we divide the power spectral densities from both microphones to obtain a ratio and use this ratio is used to scale the primary signal in the frequency domain.