Method for dynamically adjusting the spectral content of an audio signal

Abstract

A method for dynamically adjusting the spectral content of an audio signal, which increases the harmonic content of said audio signal, said method comprising translating an encoded digital signal into data bands, creating a psychoacoustic model to identify sections of said data bands that are deficient in harmonic quality, analyzing the fundamental frequency and amplitude of said harmonically deficient data bands, creating additional higher order harmonics for said harmonically deficient data bands, adding said higher order harmonics back to said encoded digital signal to form a newly enhanced signal, inverse filtering said newly enhanced signal, and converting said inverse filtered signal to an analog waveform for consumption by the listener.

What is claimed is: 
     
         1 . A method for modifying the spectral content of an audio signal, comprising the steps of:
 identifying sections of an audio signal that are deficient in harmonic quality;   adding higher order harmonics into said audio signal to form an enhanced signal; and   inverse filtering said enhanced signal.   
     
     
         2 . The method of  claim 1 , wherein said audio signal is an encoded digital signal. 
     
     
         3 . The method of  claim 1 , wherein the step of identifying includes the creation of a psychoacoustic model. 
     
     
         4 . The method of  claim 4 , wherein the audio signal is first translated into data bands, and the psychoacoustic model identifies sections of the data bands that are deficient in harmonic quality. 
     
     
         5 . The method of  claim 4 , wherein the fundamental frequency and amplitude of the harmonically deficient data bands are analyzed prior to creating additional higher order harmonics for the harmonically deficient data bands. 
     
     
         6 . The method of  claim 1 , wherein the inverse-filtered enhanced signal is a digital signal. 
     
     
         7 . The method of  claim 6 , further comprising the step of converting the inverse-filtered enhanced digital signal to an analog waveform. 
     
     
         8 . The method of  claim 4 , wherein said psychoacoustic model incorporates several layers of harmonics to identify said deficient data bands.