Encoding and decoding method and system

Abstract

In a method and apparatus for encoding a tag with an n-bit binary code one or more predetermined frequency sources are associated with the tag that produce known different respective characteristic frequencies, each of which is associated with a known unique position in the n-bit binary code,

1 . A method for decoding an n-bit binary code encoded by a tag having associated therewith one or more predetermined frequency sources each adapted to emit a respective characteristic frequency associated with a known unique position in the n-bit binary code, the method comprising: 
 (a) detecting characteristic frequencies emitted by the tag; and    (b) substituting at respective positions of said n-bit binary string respective binary values according to a presence or absence of the respective characteristic frequency associated with the respective position in the n-bit binary code.    
   
   
       2 . The method of  claim 1 , wherein at least some of the characteristic frequencies are resonant frequencies.  
   
   
       3 . The method of  claim 1 , wherein at least some of the characteristic frequencies constitute acoustic signals.  
   
   
       4 . The method of  claim 1 , including detecting at least some of the characteristic frequencies in parallel.  
   
   
       5 . The method of  claim 1 , including detecting at least some of the characteristic frequencies sequentially.  
   
   
       6 . A decoder for decoding a tag having an n-bit binary code, said decoder comprising: 
 a decoding unit responsive to one or more different characteristic frequencies each of which is associated with a known unique position in the n-bit binary code and for substituting at respective positions of said n-bit binary code respective binary values according to a presence or absence of the respective characteristic frequency associated with the respective position in the n-bit binary code.