Methods and systems for detecting cab signals

Abstract

A method is provided for distinguishing a valid locomotive control signal from an invalid control signal resulting from the presence of at least one interfering signal. The method includes detecting a signal, and transforming the signal into the frequency domain to create a transformed signal having a number of frequency domain peaks. The validity of the signal is determined based on at least of a number, a spacing, and a magnitude of the frequency domain peaks in the transformed signal.

1 . A method for distinguishing a valid locomotive control signal from an invalid control signal resulting from the presence of at least one interfering signal, said method comprising:
 detecting a signal;   transforming the signal into the frequency domain to create a transformed signal having a number of frequency domain peaks; and   determining the validity of the signal based on at least one of a number, a spacing, and a magnitude of the frequency domain peaks in the transformed signal.   
   
   
       2 . A method in accordance with  claim 1  wherein determining the validity of the signal further comprises determining that the signal is valid based on the transformed signal including a center frequency domain peak at an expected frequency and an upper and lower side band on each side of the center frequency domain peak. 
   
   
       3 . A methods method in accordance with  claim 2  further comprising using a minimum of the upper and lower side bands to acquire information regarding the signal. 
   
   
       4 . A method in accordance with  claim 2  further comprising transforming a second signal based on the center frequency domain peak and a frequency of each of the upper and lower side bands. 
   
   
       5 . A method in accordance with  claim 1  wherein determining the validity of the signal further comprises determining that the signal is invalid based on the transformed signal including a center frequency domain peak and a single side band on at one side of the center frequency domain peak. 
   
   
       6 . A method in accordance with  claim 1  wherein transforming the signal further comprises transforming the signal using at least one of a Fast Fourier transform and a Discrete Fourier Transform. 
   
   
       7 . A method in accordance with  claim 1  further comprising:
 detecting a signal determined to be a valid signal; and   filtering out at least one of other signals and noise.   
   
   
       8 . A cab signal system for a locomotive, said system comprising:
 at least one inductive pickup coil assembly configured to receive and transmit a signal; and   a signal receiver electrically coupled to said at least one inductive pickup coil assembly, said receiver configured to:   detect a signal;   transform the signal into the frequency domain to create a transformed signal having a number of frequency domain peaks; and   determine the validity of the signal based on at least one of a number, a spacing, and a magnitude of the frequency domain peaks in the transformed signal.   
   
   
       9 . A system in accordance with  claim 8  wherein said receiver is configured to determine that the signal is valid based on the transformed signal including a center frequency domain peak at an expected frequency and an upper and lower side band on each side of the center frequency domain peak. 
   
   
       10 . A system in accordance with  claim 9  wherein said receiver is further configured to use a minimum of the upper and lower side bands to acquire information regarding the signal. 
   
   
       11 . A system in accordance with  claim 9  wherein said receiver is configured to transform a second signal based on the center frequency domain peak and a frequency of each of the upper and lower side bands. 
   
   
       12 . A system in accordance with  claim 8  wherein said receiver is further configured to determine that the signal is invalid based on the transformed signal including a center frequency domain peak and a single side band on at least one side of the center frequency domain peak. 
   
   
       13 . A system in accordance with  claim 8  wherein said receiver is further configured to transform the signal using at least one of a Fast Fourier Transform and a Discrete Fourier Transform. 
   
   
       14 . A system in accordance with  claim 8  wherein said receiver is further configured to:
 detect a signal determined to be a valid signal; and   filter out at least one of other signals and noise.   
   
   
       15 . A cab signal receiver configured to:
 detect a signal;   transform the signal into the frequency domain to create a transformed signal having a number of frequency domain peaks; and   determine the validity of the signal based on at least one of a number, a spacing, and a magnitude of the frequency domain peaks in the transformed signal.   
   
   
       16 . A cab signal receiver in accordance with  claim 15  configured to determine that the signal is valid based on the transformed signal including a center frequency domain peak at an expected frequency and an upper and lower side band on each side of the center frequency domain peak. 
   
   
       17 . A cab signal receiver in accordance with  claim 16  further configured to use a minimum of the upper and lower side bands to acquire information regarding the signal. 
   
   
       18 . A cab signal receiver in accordance with  claim 16  configured to transform a second signal based on the center frequency domain peak and a frequency of each of the upper and lower side bands. 
   
   
       19 . A cab signal receiver in accordance with  claim 15  further configured to determine that the signal is invalid based on the transformed signal including a center frequency domain peak and a single side band on at least one side of the center frequency domain peak. 
   
   
       20 . A cab signal receiver in accordance with  claim 15  further configured to transform the signal using at least one of a Fast Fourier Transform and a Discrete Fourier Transform.