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 . An interrogator comprising: 
 a code generator for generating a first pseudo-noise sequence;    a code generator for generating a second pseudo-noise sequence;    first logic circuitry for encoding the first pseudo-noise sequence with a data signal to create a spread data signal;    second logic circuitry for randomly inverting the spread data signal using the second pseudo-noise sequence; and    a summing amplifier for outputting a tri-state signal using the second pseudo-noise signal and a randomly inverted spread data signal.    
     
     
         49 . The interrogator of  claim 48 , wherein the first logic circuitry is an exclusive OR device.  
     
     
         50 . The interrogator of  claim 48 , wherein the second logic circuitry is an exclusive OR device.  
     
     
         51 . The interrogator of  claim 48 , wherein logical high values in the tri-state signal are represented by both positive voltages and negative voltages.  
     
     
         52 . The interrogator of  claim 48 , further comprising: 
 a low pass filter coupled to the output of the summing amplifier for reducing harmonic information in the tri-state signal.    
     
     
         53 . The interrogator of  claim 48 , further comprising: 
 a mixer for receiving the tri-state signal and a carrier signal.    
     
     
         54 . The interrogator of  claim 53 , wherein the mixer inverts a phase of the carrier signal in response to a negative value in the tri-state signal.