employing multiple processor designs for increased computing capability the algorithms and displays presented herein are not inherently related to any particular computer or other apparatus various general purpose systems may also be used with programs in accordance with the teachings herein or it may prove convenient to construct more specialized apparatus to perform the required method steps the required structure for a variety of these systems will appear from the description below in addition the present invention is not described with reference to any particular programming language it will be appreciated that a variety of programming languages may be used to implement the teachings of the present invention as described herein and any references below to specific languages are provided for disclosure of enablement and best mode of the present invention in addition the language used in the specification has been principally selected for readability and instructional purposes and may not have been selected to delineate or circumscribe the inventive subject matter accordingly the disclosure of the present invention is intended to be illustrative but not limiting of the scope of the invention which is set forth in the claims according to a first aspect of the present invention a non linear smoothing of an input signal is proposed let x k be the envelope of the input signal and x s k the smoothed envelope then x s u2061 k 0 k 0 x u2061 k x s u2061 k 1 u2264 x u2061 k u22c0.