Low-frequency sound source for underwater sound propagation research and calibration

Abstract

A variable inductor includes a three-limbed core first section having an inductor winding wound about a medial limb. An air gap is disposed in the medial limb. The inductor includes a second section having a control limb in which a first end of the control limb is connected to a first outer limb of the three-limbed core, and a second end of the control limb is connected to a second outer limb of the three-limbed core. A control winding is wound about the control limb. The inductor may be used in a control circuit to control a power signal driving a transducer. The inductor may be controlled by a signal derived from a comparison of a voltage phase of a power signal to the transducer and a phase of the current traversing the transducer. A system may include the control circuit, including the variable inductor, and the transducer.

1 . A variable inductor, comprising:
 a first core, comprising:
 a first outer limb; 
 a second outer limb; 
 a medial limb disposed between the first outer limb and the second outer limb; 
 a first framing portion coupled to a first side of the first outer limb, a first side of the second outer limb, and a first side of the medial limb; 
 a second framing portion coupled to a second side of the first outer limb and a second side of the second outer limb; 
 an air gap disposed between a second side of the medial limb and the second framing portion; and 
 a variable inductor winding wound on the medial limb; and 
   a second core, comprising:
 a control core limb; and 
 a control winding wound on the control core limb, 
   wherein a first side of the control core limb is coupled to the first outer limb and a second side of the control core limb is coupled to the second outer limb.   
     
     
         2 . The variable inductor of  claim 1 , wherein the first outer limb, the second outer limb, and the medial limb define a first plane and the control core limb is disposed on a second plane orthogonal to the first plane. 
     
     
         3 . The variable inductor of  claim 1 , wherein the first side of the control core limb is coupled to a medial portion of the first outer limb and the second side of the control core limb is coupled to a medial portion of the second outer limb. 
     
     
         4 . The variable inductor of  claim 1 , further comprising:
 a first permanent magnet disposed between the control core limb and the first outer limb; and   a second permanent magnet disposed between the control core limb and the second outer limb.   
     
     
         5 . The variable inductor of  claim 4 , wherein the first permanent magnet has a first magnetization direction, the second permanent magnet has a second magnetization direction, and the first magnetization direction of the first permanent magnet is the same as the second magnetization direction of the second permanent magnet. 
     
     
         6 .- 27 . (canceled)