Backscatter interrogators, communication systems and backscatter communication methods

Abstract

The present invention provides backscatter interrogators, communication systems and backscatter communication methods. According to one aspect of the present invention, a backscatter interrogator includes a data path configured to communicate a data signal; a signal generator configured to generate a carrier signal; and a modulator coupled with the data path and the signal generator, the modulator being configured to spread the data signal to define a spread data signal and amplitude modulate the carrier signal using the spread data signal, the modulator being further configured to phase modulate the carrier signal.

1 - 47 . (canceled)  
     
     
         48 . A method of operating an interrogator comprising: 
 encoding a first pseudo-noise sequence with a data signal to create a first spread data signal;    randomly inverting the first spread data signal using a second pseudo-noise sequence to create a second spread data signal, wherein one or more chips in the first spread data signal are inverted when the first spread data signal has a logical low value; and    creating a tri-state signal from the second pseudo-noise sequence and the second spread data signal.    
     
     
         49 . The method of  claim 48 , further comprising: 
 reducing harmonic information within the tri-state signal using a low-pass filter; and    applying an output of the low-pass filter to an attenuator.    
     
     
         50 . The method of  claim 48 , wherein randomly inverting the first spread data signal implements phase modulation.  
     
     
         51 . The method of  claim 48 , further comprising: 
 modulating a carrier signal using the tri-state signal.    
     
     
         52 . The method of  claim 48 , further comprising: 
 band limiting the first spread data signal.    
     
     
         53 . The method of  claim 48 , further comprising: 
 inverting a phase of a carrier signal mixed with a negative value of the tri-state signal.    
     
     
         54 . The method of  claim 48  further comprising: 
 mixing a carrier signal with the tri-state signal.