Induction-based assistive listening system

A system for addressing a selected audience of hard-of-hearing persons by the generation of specifically configured magnetic fields in the vicinity of pick-up coils worn by said audience comprising:

• (a) transducer means for converting an input signal into an electrical voltage singal processing substantially the same Fourier spectrum as said input signal;
• (b) means for separating said electrical voltage signal into a multiplicity of current signal, phase shifted with respect to one another, in which each Fourier component of a particular member of said multiplicty of current signals has a unique phase shift with respect to the corresponding Fourier component in each of the other members of said multiplicity of current signals;
• (c) an essentially planar arragement of substantially rectangular, electrically isolated conduction loops, each of said conduction loops having a length dimension and a width dimension, said conduction loops further arranged such that there exists a first loop which has an orientation with respect to said first loop's length dimension and at least one additional conduction loop which has an orientation with respect to said additional loop's length dimension which is essentially perpendicular to said orientation of said first loop and a further conduction loop which has an orientation with respect to said further loop's length dimension which is essentially parallel to said orientation of said first loop such that magnetic fields induced by current flowing through said conduction loops are of substantially uniform strength in a plane parallel to said mat when measured in an area above said conduction loops, but said magnetic fields are of substantially reduced strength outside of the area of said conduction loops;
• and
• (d) means for connecting each of said phase-shifted current signals to a separate conduction loop of said arrangement of conduction loops, wherein a voltage signal corresponding to said input is induced in said pick-up coils of said audience.

A modular system for addressing a selected audience of hard-of-hearing persons by the generation of specifically configured magnetic fields in the vicinity of pick-up coils worn by said audience comprising:

• (a) transducer means for converting an input signal into an electrical voltage signal processing substantially the same Fourier spectrum as said input signal;
• (b) means for separating said electrical voltage signal into a multiplicity of current signals, phase shifted with respect to one another, in which each Fourier component of a particular member of said multiplicity of current signals has a unique phase shift with respect to the corresponding Fourier component in each of the other members of said multiplicity of current signals;
• (c) a plurality of flexible mats comprising:
• (i) a bottom layer of flexible material;
• (ii) An essentially planar arrangement of at least three substantially rectangular, electrically isolated conduction loops, each of said conduction loops having loops further arranged such that there exists a first loop which has an orientation with respect to said first loop's length dimension and at least one additioal conduction loop which has an orientation with respect to said additional loop's length dimension which is essentially perpendicular to said orientation of said first loop and a further conduction loop which has an orientation with respect to said further loop's length dimension which is essentially parallel to said orientation of said first loop such that magnetic fields induced by current flowing through said conduction loops are of substantially uniform strength in a plane parallel to said mat when measured in an area above said mat, but said magnetic fields are of substantially reduced strength outside of the area of said mat;
• and
• (iii) a top layer of flexible material;
• and
• (d) means for connecting each of said phase-shifted current signals to a separate conduction loop of said arrangement of conduction loops, wherein a voltage signal corresponding to said input signal is induced in said pick-up coils of said audience.

A method of addressing a selected audience of hard-of-hearing persons by the generation of specially configured magnetic fields in the vicinity of pick-up coils worn by members of said audience comprising:

• (a) converting an input signal into an electrical voltage signal possessing substantially the same Fourier spectrum as said input signal;
• (b) separating said electrical voltage signal into a multiplicity of current signals, phase shifted with respect to one another, in which each Fourier component of a particular member of said multiplicity of current signals has a unique phase shift with respect to the corresponding Fourier component in each of the members of said multiplicity of current signals;
• (c) conducting each of said current signals into a corresponding electrically isolated conduction loop, each conduction loop having a substantially rectangular configuration and a length dimension and a width dimension, wherein a voltage signal corresponding to said input signal is induced in said pick-up coil of a member of said audience, said conduction loops situated in an essentially planar configuration such that there exists a first conduction loop which has an orientation of said first loop and at least one further conduction loop which has an orientation with respect to said first loop's length dimension and at least one additional conduction loop which has an orientation with respect to said additional loop's length dimension which is essentially perpendicular to said orientation with respect to said further loop's length dimension which is essentially parallel to said orientation of said first loop such that magnetic fields induced by current flowing through said conduction loops are of substantially uniform strength in a plane parallel to said mat when measured in an area above said conduction loops, but said magnetic fields are of substantially reduced strength outside of the area of said conduction loops.