Patent ID: 7076073
Filing Date: 2006-07-11
Classification: G01R,H04R

Abstract:
1. A method of approximating a root-mean-square (RMS) value for an audio signal in a digital hearing aid, comprising the steps of: receiving the audio signal; rectifying the audio signal to generate a rectified signal; determining a difference between the rectified signal and an estimated present energy value of the audio signal; if the difference is not greater than zero, then multiplying the rectified signal by a release time constant to generate a first filtered signal and summing the first filtered signal with the estimated present energy value to determine the approximate RMS value; and if the difference is greater than zero, then multiplying the rectified signal by an attack time constant to generate a second filtered signal and summing the second filtered signal with the estimated present energy value to determine the approximate RMS value; wherein the attack time constant is less than the release time constant.