For a uniform beam pattern, what is the expected amplitude relationship between laminar reflections at two opposite points along the beam?

For a uniform beam pattern, what is the expected amplitude relationship between laminar reflections at two opposite points along the beam?

• A. 12 dB difference
• B. Equal amplitudes
• C. 2 to 1
• D. 3 to 1

Answer: (C)

In a uniform beam pattern, the energy illumination is the same across the beam, so the difference between laminar reflections from two opposite points along the beam mainly comes from the travel distance of the sound to and from those points. The reflection from the point closer to the transducer travels a shorter path and experiences less attenuation, while the reflection from the opposite point travels a longer path and loses more energy. In typical geometries for a uniform beam, that extra distance reduces the far-side reflection to about half the amplitude of the near-side reflection, giving a 2 to 1 relationship. So the nearer lamination tends to reflect with roughly twice the amplitude of the opposite one. Equal amplitudes would require identical path lengths; a 12 dB difference (about a fourfold change) or a 3 to 1 ratio would imply much larger or different path differences than what a simple uniform beam and two opposite points produce.

In a uniform beam pattern, the energy illumination is the same across the beam, so the difference between laminar reflections from two opposite points along the beam mainly comes from the travel distance of the sound to and from those points. The reflection from the point closer to the transducer travels a shorter path and experiences less attenuation, while the reflection from the opposite point travels a longer path and loses more energy. In typical geometries for a uniform beam, that extra distance reduces the far-side reflection to about half the amplitude of the near-side reflection, giving a 2 to 1 relationship. So the nearer lamination tends to reflect with roughly twice the amplitude of the opposite one. Equal amplitudes would require identical path lengths; a 12 dB difference (about a fourfold change) or a 3 to 1 ratio would imply much larger or different path differences than what a simple uniform beam and two opposite points produce.