Patent ID: 9408001
Filing Date: 2016-08-02
CPC Classification: H03G,H04R

Claim Text:
1. A method for compressively amplifying an audio signal, comprising: inputting the audio signal to a fast signal level estimator (fast SLE) having a fast low-pass filter characterized by a rise time constant and a decay time constant; inputting the audio signal to a slow signal level estimator (slow SLE) having a slow low-pass filter characterized by a rise time constant and a decay time constant; subtracting the output of the slow SLE from the output of the fast SLE and inputting the result to a fast level-to-gain transformer; inputting the output of the slow SLE to a slow level-to-gain transformer, wherein the slow level-to-gain transformer is characterized by expansion when the output of the slow SLE is below a specified threshold; and, amplifying the audio signal with a gain adjusted by a summation of the outputs of the fast level-to-gain transformer and the slow level-to-gain transformer, wherein the output of the fast level-to-gain transformer is multiplied by a weighting factor computed as a function of the output of the slow SLE before being summed with the output of the slow level-to-gain transformer.