Methods and systems for multi-tuned cab signal pickup coils

Abstract

Methods and systems for a cab signal pickup coil assembly are provided. The system includes an assembly including at least one elongate magnetic core and a plurality of pickup coils concentrically spaced about the magnetic core wherein the pickup coils are configured to be responsive to a magnetic field in the magnetic core. The pickup coils are grouped in sets of pickup coils along an axial length of the magnetic core. At least two sets of pickup coils are at least partially tuned using respective tuning capacitors to be responsive to different respective cab signal carrier frequencies.

1 . A cab signal pickup coil assembly comprising:
 at least one elongate magnetic core; and   a plurality of pickup coils concentrically spaced about said magnetic core, said pickup coils configured to be responsive to an alternating magnetic field in said magnetic core, said pickup coils grouped in sets of pickup coils along an axial length of said magnetic core, at least two sets of pickup coils at least partially tuned by respective tuning capacitors to be responsive to different respective cab signal carrier frequencies.   
   
   
       2 . A system in accordance with  claim 1  wherein said magnetic core comprises a longitudinal axis, said magnetic core is configured to be positioned proximate a rail such that a longitudinal axis of the rail is substantially orthogonal with respect to the longitudinal axis of the magnetic core. 
   
   
       3 . A system in accordance with  claim 1  wherein ones of said sets of pickup coils are separated from an adjacent set of pickup coils by an air gap. 
   
   
       4 . A system in accordance with  claim 1  wherein said tuning capacitors comprise an electrically controlled variable capacitor. 
   
   
       5 . A system in accordance with  claim 1  wherein the capacitance of the tuning capacitors is at least one of switchable, variable, and digitally variable such that a frequency response of the sets of pick up coils is variable. 
   
   
       6 . A system in accordance with  claim 1  wherein sets of pickup coils are separated from adjacent sets of pickup coils by a material having a predetermined reluctance. 
   
   
       7 . A system in accordance with  claim 1  wherein pick up coils in a set are electrically coupled in series. 
   
   
       8 . A system in accordance with  claim 1  wherein at least one set of pickup coils reduces noise above and below a first cab signal carrier frequency and has a center frequency between about 40 Hz and about 250 Hz. 
   
   
       9 . A system in accordance with  claim 1  wherein at least one set of pickup coils reduces noise above and below a first cab signal carrier frequency and has a center frequency of about 100 Hz. 
   
   
       10 . A system in accordance with  claim 1  wherein at least one set of pickup coils reduces noise above and below a second cab signal carrier frequency and has a center frequency between about 1500 Hz and about 4550 Hz. 
   
   
       11 . A system in accordance with  claim 1  wherein at least one set of pickup coils reduces noise above and below a first cab signal carrier frequency and has a center frequency of about 2050 Hz. 
   
   
       12 . A cab signal system comprising:
 a receiver configured to be mounted on board a locomotive;   at least one pickup coil assembly communicatively coupled to said receiver, said at least one pickup coil assembly configured to sense an alternating magnetic field around a rail of a railroad track produced by control information transmitted through the rail wherein the control information is transmitted using a plurality of carrier frequencies, said at least one pickup coil assembly comprising sets of pick up coils each tuned to one of the plurality of carrier frequencies.   
   
   
       13 . A system in accordance with  claim 12  further comprising a pickup coil assembly mount configured to couple said pickup coil assembly to a locomotive such that a longitudinal axis of said pickup coil assembly is substantially orthogonal with respect to the track. 
   
   
       14 . A system in accordance with  claim 12  wherein said at least one pickup coil assembly comprises:
 an elongate core; and   at least one pickup coil concentrically mounted around said elongate core.   
   
   
       15 . A system in accordance with  claim 12  wherein said tuning capacitor is external to said pickup coil assembly 
   
   
       16 . A system in accordance with  claim 12  wherein said at least one pickup coil assembly comprises a coil wound with a plurality of adjacent turns concentrated axially along an elongate core and a tuning capacitor coupled electrically in parallel. 
   
   
       17 . A method of receiving a railway cab signal on board a railway vehicle comprises:
 receiving control information transmitted through railroad rails to a signal coil assembly mounted on board the railway vehicle using a carrier having a frequency in a first predetermined range; and   receiving control information transmitted through railroad rails to the signal coil assembly using a carrier having a frequency in a second predetermined range, wherein the first and second predetermined ranges are different, the first and second predetermined frequency ranges selected based on a tuning of coils within the signal coil assembly.   
   
   
       18 . A method in accordance with  claim 17  further comprising traversing from a first locale where cab signals are transmitted using a carrier having a frequency in a first predetermined range predominate to a second locale where cab signals are transmitted using a carrier having a frequency in a second predetermined range predominate. 
   
   
       19 . A method in accordance with  claim 17  further comprising mounting a signal coil assembly to the railway vehicle such that a longitudinal axis of the signal coil assembly is maintained substantially orthogonal with respect to the rail. 
   
   
       20 . A method in accordance with  claim 17  further comprising positioning a plurality of pickup coils concentrically spaced about a signal coil assembly magnetic core wherein the pickup coils are configured to be responsive to an alternating magnetic field in the magnetic core, the pickup coils being grouped in sets of pickup coils along the magnetic core wherein at least two sets of pickup coils are at least partially tuned using a respective tuning capacitor to be responsive to different respective cab signal carrier frequencies.