Method and apparatus for envelope detection and enhancement of pitch cue of audio signals

Abstract

A method and apparatus for detecting an envelope of an audio signal, and a method and apparatus for enhancing the pitch cue of an audio signal perceived by a cochlear implant patient where the audio signal is processed and input to an implant device of the recipient. The methods and apparatuses use techniques such as filtering, rectifying, detecting peak values, sampling, resetting, comparing and multiplying various signals to detect the envelope or enhance the pitch cue of the audio signal.

1 - 74 . (canceled)  
   
   
       75 . A method of detecting an envelope of an audio signal comprising the steps of: 
 filtering the audio signal to produce a filtered audio signal;    rectifying the filtered audio signal to produce a rectified signal;    detecting peak values of the rectified signal to produce a detected signal;    sampling the detected signal at predetermined time intervals to produce samples; and    resetting the detected signal immediately after sampling.    
   
   
       76 . The method according to  claim 75 , wherein the rectifying step uses half wave rectification.  
   
   
       77 . The method according to  claim 75 , wherein the rectifying step uses full wave rectification.  
   
   
       78 . The method according to  claim 75 , wherein the detected peak values remain at a substantially constant value prior to the sampling step.  
   
   
       79 . The method according to  claim 78 , wherein the detected signal or detected signals is reset substantially to zero.  
   
   
       80 . The method according to  claim 75 , wherein the sampling rate used in the sampling step is relatively low compared to frequency components in the filtered audio signal.  
   
   
       81 . The method according to  claim 75 , wherein the audio signal is input to a cochlear implant device.  
   
   
       82 . An apparatus for detecting an envelope of an audio signal comprising: 
 means for filtering the audio signal to produce a filtered audio signal;    means for rectifying the filtered audio signal to produce a rectified signal;    means for detecting the peak values of the rectified signal to produce a detected signal;    means for sampling the detected signal at predetermined time intervals to produce samples; and    means for resetting the means for detecting immediately after sampling, such that the detected signal is reset immediately following sampling.    
   
   
       83 . The apparatus according to  claim 82 , wherein the means for rectifying is one or more full wave rectifiers.  
   
   
       84 . The apparatus according to  claim 82 , wherein the means for rectifying is one or more half wave rectifiers.  
   
   
       85 . The apparatus according to  claim 82 , wherein the detected peak values remain at a substantially constant value prior to sampling.  
   
   
       86 . The apparatus according to  claim 85 , wherein the detected signal or detected signals is reset substantially to zero.  
   
   
       87 . The apparatus according to  claim 82 , wherein the sampling rate used by the means for sampling is relatively low compared to frequency components in the filtered audio signal.  
   
   
       88 . The apparatus according to  claim 82 , wherein the audio signal is input to a cochlear implant device.