ULTRASONIC DELAY LINES

• US 3,736,532 A
• Filed: 07/14/1971
• Issued: 05/29/1973
• Est. Priority Date: 07/14/1971
• Status: Expired due to Term

• Current Assignee: Anthony E. Armenakas
• Original Assignee: Anthony E. Armenakas
• Inventors: Armenakas, Anthony E.
• Primary Examiner(s): Rolinec, Rudolph V.
• Assistant Examiner(s): Punter, Wm. H.
• Application Number:
  US05/162,583
• Time in Patent Office: 685 Days
• Field of Search: 333/3R,3M,71,72,32
• US Class Current: 333/145
• CPC Class Codes: H03H 9/0222 of interface-acoustic, boundary, pseudo-acoustic or Stonely wave devices
• CPC Class Codes: H03H 9/40 Frequency dependent delay lines, e.g. dispersive delay lines H03H9/42 takes precedence

Abstract

Delay lines with a variety of delay versus frequency characteristics are obtained by fabricating the delay line apparatus from multilayer materials. In one modification, the delay line is of rod construction and in another, of strip design.

Claims

1. A solid delay line comprising, in combination, a first cylindrical shell member made of a material that is capable of propagating elastic waves;

an input interdigital electrode transducer secured to the inner wall surface of said shell member at a position adjacent one end thereof;

an output interdigital electrode transducer secured to the inner wall surface of said shell member at a location adjacent the other end thereof;

said transducers being in alignment such that an elastic wave excited by said input transducer is subsequently detected by said output transducer;

a second cylindrical shell member made of a different material that is also capable of propagating elastic waves, the inner surface of said second cylindrical shell member being bonded to the outer surface of said first inner cylindrical shell member over their common length, the thickness of said first cylindrical shell member being such that said elastic wave also travels through portions of said second cylindrical shell member.

2. A delay line comprising in combination a solid rod made of a first material that is capable of propagating elastic waves;

an input transducer secured to one end of said rod;

an output transducer secured to the other end of said rod;

a first cylindrical shell member having a length less than that of said rod bonded to the outer surface of said rod, said shell member being made of a second material that is also capable of propagating elastic waves;

a second cylindrical shell member having a length less than that of said first cylindrical shell member, said second cylindrical shell member being bonded to the outer surface of said first cylindrical shell member and being made of a material that is capable of propagating elastic waves, The lengths of said rod, and said first and second cylindrical shell members and the density and stiffness ratios of said rod and said first and second cylindrical shell members being selected to achieve the signal time delay desired.

3. A solid delay line comprising in combination a pair of unequal length strips made of different metals that are capable of propagating elastic waves;

said strips being bonded together over their common length and having a thickness such that any elastic wave excited in the longer strip travels also within the shorter strip when it reaches one end of this strip;

an input transducer secured to one end face of the longer strip;

an output transducer secured to the other end face of said longer strip;

a third strip having a length less than the longer strip of said pair and bonded to said longer strip over its length, said elastic wave also traveling within said third strip when it reaches one end thereof;

the lengths of said strips and their denSity and stiffness ratios being selected to obtain the desired signal time delay.