Patent ID: 8873782

Claim:
A device for compressing an audio signal, comprising a fast signal level estimator (fast SLE) and a slow signal level estimator (slow SLE) for receiving the audio signal, each SLE having a low-pass filter characterized by a rise time constant and a decay time constant; a fast level-to-gain transformer for transforming a signal level estimate to a gain value; a slow level-to-gain transformer for transforming a signal level estimate to a gain value; an output amplifier having an adjustable gain for amplifying the audio signal; circuitry configured such that the output of the slow SLE is subtracted from the output of the fast SLE and then input to the fast level-to-gain transformer; circuitry configured such that the output of the slow SLE is input to the slow level-to-gain transformer; circuitry configured so that the gain values of the fast level-to-gain transformer and the slow level-to-gain transformer are summed to adjust the gain of the output amplifier; and, circuitry so that the gain value of the fast level-to-gain transformer is multiplied by a weighting factor before being summed with the gain value of the slow level-to-gain transformer.