From Transducers and Arrays for Underwater Sound
- Acoustic Beam
- Acoustic waves concentrated mainly in a limited direction.
- Acoustic Center of a Transducer
- The apparent center of the spherical waves in the far field of a transducer.
- Acoustic Impedance
- The complex ratio of acoustic pressure to amplitude of volume velocity.
- Acoustic Medium
- Any material through which acoustic waves can travel, usually air or water, but also other fluids and solids.
- Acoustic Modem
- Underwater device which communicates by means of acoustic waves.
- Active Sonar
- Detection of a target by projecting acoustic waves and listening for an echo, also called echo ranging.
- Admittance, Y
- 1) The reciprocal of the impedance, Z. 2) Y = G + jB where G is the conductance and B is the susceptance.
- Antiresonance, f a
- 1) For an electric field transducer, the frequency at which the mass and open-circuit stiffness cancel or the frequency of maximum impedance or RVS. 2) For a magnetic field transducer, the frequency at which the mass and short-circuit stiffness cancel or the frequency of maximum admittance or TVR.
- 1) Part of a magnetic circuit. 2) The moveable part of the magnetic circuit in a variable reluctance transducer.
- Array of Transducers
- Two or more transducers that are used together usually to achieve a higher intensity and narrower beam.
- 1) Hypocyloid of four cusps. 2) Described by a point on a small circle of radius, R, rolling around the inside of a larger circle of radius 4R.
- Beam steering
- Changing the principal direction of an acoustic beam by changing...
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