Transition section for acoustic waveguides

Claim 2

An acoustic impedance matching section for effecting a transition between a first solid acoustic waveguide having a first specific acoustic impedance and a first cross-sectional area and a second solid acoustic waveguide having a second specific acoustic impedance and a second cross-sectional area, said second cross-sectional area equalling the product of the ratio of the first specific acoustic impedance to the second acoustic impedance times the first cross-sectional area, said matching section comprising: a structure having a first end connected to the first waveguide with said first end congruent to said first cross-sectional area; a second end parallel to said first end connected to said second waveguide with said second end congruent to said second cross-sectional area; said matching section further being made of materials having values of specific acoustic impedance equal to said first and second specific acoustic impedances and faired from said first end to said second end to maintain at each cross section of said matching section parallel to said first and second ends an equal value of the sum of the products of the cross-sectional areas of each material and specific acoustic impedance thereof.

Claim 3

A transition section between a first cylindrical acoustic transmission medium having a first diameter, a first value of cross-sectional area and a first value of specific acoustic impedance, and a second cylindrical acoustic transmission medium having a second value of specific acoustic impedancE and a second cross-sectional area equal to the product of the first value of cross-sectional area times the ratio of the first value of specific acoustic impedance to the second value of specific acoustic impedance, said second cylindrical acoustic transmission medium having a second diameter, said transition section having an axis, said transition section comprising: a first portion of a material having a value of specific acoustic impedance equal to said first value of specific acoustic impedance, said first portion a cone coaxial with said axis with a circular base connected to said first acoustic transmission medium and an apex touching said second acoustic transmission medium, said circular base having a diameter equal to the ratio of the products of said first and second diameters to the sum of said first and second diameters; a second portion of a material having a value of specific acoustic impedance equal to said second value of specific acoustic impedance, said second portion coaxial with said first portion and connected to said first portion on the conical surface thereof, said second portion forming with said first portion a frustum of a cone having a base congruent to said second cross-sectional area and connected at said base to said second cylindrical acoustic transmission medium, said frustum bounded at an end opposite to said base by said circular base of said first portion; and a third portion of a material having a value of specific acoustic impedance equal to said first value of specific acoustic impedance, said third portion coaxial with said first and second portions, said third portion connected to said second portion on the conical surface thereof, said third portion forming with said first and second portions a frustum of a cone having a base that is the base of said second portion, said frustum having a top that is the base of said first portion.

Claim 4

A transition section between a first cylindrical acoustic transmission medium having a first diameter, a first value of cross-sectional area and a first value of specific acoustic impedance, and a second cylindrical acoustic transmission medium having a second value of specific acoustic impedancE and a second cross-sectional area equal to the product of the first value of cross-sectional area times the ratio of the first value of specific acoustic impedance to the second value of specific acoustic impedance, said second cylindrical acoustic transmission medium having a second diameter, said transition section having an axis, said transition section comprising: a first portion of a material having a value of specific acoustic impedance equal to said first value of specific acoustic impedance, said first portion a cone coaxial with said axis with a circular base connected to said first acoustic transmission medium and an apex touching said second acoustic transmission medium, said circular base having a diameter equal to the ratio of the products of said first and second diameters to the sum of said first and second diameters; a second portion of a material having a value of specific acoustic impedance equal to said second value of specific acoustic impedance, said second portion coaxial with said first portion and connected to said first portion on the conical surface thereof, said second portion forming with said first portion a frustum of a cone having a base congruent to said second cross-sectional area and connected at said base to said second cylindrical acoustic transmission medium, said frustum bounded at an end opposite to said base by said circular base of said first portion; and a third portion of a material having a value of specific acoustic impedance equal to said first value of specific acoustic impedance, said third portion coaxial with said first and second portions, said third portion connected to said second portion on the conical surface thereof, said third portion forming with said first and second portions a frustum of a cone having a base that is the base of said second portion, said frustum having a top that is the base of said first portion.

Claim 5

An apparatus for detecting with minimal reflection and displaying acoustical signals from an acoustical source comprising: a metal rod coupled acoustically to said source; a first transition section constructed according to claim 2 connected at an input end to said rod; a first thin layer of alumina connected to said first transition section at an output end to provide electrical insulation; a first brass disk connected to said first layer of alumina and coupled acoustically therethrough to said first transition section; a piezoelectric crystal of lead zirconate titanate connected electrically and acoustically to said first brass disk at a first side; a second brass disk connected to said piezoelectric crystal at a second side opposite to said first side, said first and second sides selected to generate a piezoelectric voltage therebetween; a second thin layer of alumina connected to said second brass disk to provide with said first thin layer electrical isolation of said first and second disks and said piezoelectric crystal from other parts of said apparatus; a second transition section constructed according to claim 2 connected at an input end to said second thin layer of alumina and coupled acoustically therethrough to said second brass disk; a termination section made of powdered metal cast in plastic, said termination section coupled mechanically and acoustically to said second transition section at an output portion thereof; and display means connected electrically to said first and second brass disks and responsive to said piezoelectric voltage therebetween to generate a display signal in response to said piezoelectric voltage, which display signal displays said acoustical signals with minimal reflection.

Claim 6

A transition section between a first solid cylindrical acoustic waveguide having a first diameter and a first value of acoustic impedance and a second solid cylindrical acoustical waveguide coaxial with said first waveguide and having a second diameter and a second value of acoustic impedance, said transition section comprising: a first portion coaxial with said first and second waveguides, said first portion formed of a material having the same specific acoustic impedance as said second waveguide, said first portion a cone with an apex at a first plane perpendicular to the axis of said first and second waveguides, said cone having a base connected to said second waveguide in a circle having a diameter equal to the diameter of said second waveguide, said base congruent to said circle; and a second portion coaxial with said first and second waveguides, connected to said first waveguide at said first plane, said second portion made of a material having a value of specific acoustic impedance equal to the specific acoustic impedance of said first waveguide, said second portion bounded on the inside by said cone coaxial with said first and second acoustic waveguides, said cone having an apex in said first plane, said cone having a base congruent to said second waveguide, said second portion bounded on the outside by a hyperboloid of revolution intersecting said first waveguide on a circle formed by the intersection of said first plane with the outside of said first waveguide and intersecting said second waveguide at said base of said cone, said hyperboloid of revolution calculated to maintain at each cross section of said transition section an equal value of the sum of the product of area and specific impedance of said first and second portions.

Claim 7

A transition section between a first solid cylindrical acoustic waveguide having a first diameter and a first value of acoustic impedance and a second solid cylindrical acoustical waveguide coaxial with said first waveguide and having a second diameter and a second value of acoustic impedance, said transition section comprising: a first portion coaxial with said first and second waveguides, said first portion formed of a material having the same specific acoustic impedance as said second waveguide, said first portion a cone with an apex at a first plane perpendicular to the axis of said first and second waveguides, said cone having a base connected to said second waveguide in a circle having a diameter equal to the diameter of said second waveguide, said base congruent to said circle; and a second portion coaxial with said first and second waveguides, connected to said first waveguide at said first plane, said second portion made of a material having a value of specific acoustic impedance equal to the specific acoustic impedance of said first waveguide, said second portion bounded on the inside by said cone coaxial with said first and second acoustic waveguides, said cone having an apex in said first plane, said cone having a base congruent to said second waveguide, said second portion bounded on the outside by a hyperboloid of revolution intersecting said first waveguide on a circle formed by the intersection of said first plane with the outside of said first waveguide and intersecting said second waveguide at said base of said cone, said hyperboloid of revolution calculated to maintain at each cross section of said transition section an equal value of the sum of the product of area and specific impedance of said first and second portions.

Claim 8

A transition section between a first solid cylindrical acoustic waveguide having a first diameter and a first value of specific acoustic impedance and a second solid cylindrical acoustic waveguide coaxial with said first waveguide and having a second diameter and a second value of acoustic impedance, said transition section comprising: a first portion coaxial with said first and second waveguides and formed of a material having a specific acoustic impedance equal to that of said first waveguide, said first portion bounded on the outside by a frustum of a cone congruent in a circular plane with a cross section of said first waveguide and touching said second waveguide in a circle of a diameter equal to the diameter of said second waveguide, said first portion bounded on the inside by a hyperboloid of revolution coaxial with said first and second waveguides, said hyperboloid of revolution tangent to said circular plane at its center, said hyperboloid of revolution terminating in said circle of a diameter equal to the diameter of said second waveguide, said hyperboloid of revolution calculated to maintain at each cross section perpendicular to the axis of said transition section equality of the sums of the products of area and specific acoustic impedance when the volume inside said hyperboloid of revolution is filled with a material having a specific acoustic impedance equal to the specific acoustic impedance of said second acoustic waveguide; and a second portion of a material having a specific acoustic impedance equal to the specific acoustic impedance of said second acoustic waveguide, said second portion bounded by said hyperboloid of revolution and by said circle of a diameter equal to the diameter of said second acoustic waveguide, the combination of said first and second portions filling the volume of said frustum of a cone.

Claim 9

A transition section between a first solid cylindrical acoustic waveguide having a first diameter and a first value of specific acoustic impedance and a second solid cylindrical acoustic waveguide coaxial with said first waveguide and having a second diameter and a second value of acoustic impedance, said transition section comprising: a first portion coaxial with said first and second waveguides and formed of a material having a specific acoustic impedance equal to that of said first waveguide, said first portion bounded on the outside by a frustum of a cone congruent in a circular plane with a cross section of said first waveguide and touching said second waveguide in a circle of a diameter equal to the diameter of said second waveguide, said first portion bounded on the inside by a hyperboloid of revolution coaxial with said first and second waveguides, said hyperboloid of revolution tangent to said circular plane at its center, said hyperboloid of revolution terminating in said circle of a diameter equal to the diameter of said second waveguide, said hyperboloid of revolution calculated to maintain at each cross section perpendicular to the axis of said transition section equality of the sums of the products of area and specific acoustic impedance when the volume inside said hyperboloid of revolution is filled with a material having a specific acoustic impedance equal to the specific acoustic impedance of said second acoustic waveguide; and a second portion of a material having a specific acoustic impedance equal to the specific acoustic impedance of said second acoustic waveguide, said second portion bounded by said hyperboloid of revolution and by said circle of a diameter equal to the diameter of said second acoustic waveguide, the combination of said first and second portions filling the volume of said frustum of a cone.