An ultrasound transducer is pointing down the z-axis, on which two point scatte...

An ultrasound transducer is pointing down the z-axis, on which two point scatterers are located at z₁ and z₂ in the Fraunhofer field (see Figure P11.1). The transducer fires a narrowband burst with a rect-shaped envelope in the +z direction. The envelope is n_e(t) = rect((t + T/2)/T) where T = λ/2c, λ is the wavelength, and c is the speed of sound in the material. Sketch the estimated reflectivity for

(a) z ₂ – z₁ = λ/2.

(b) z ₂− z₁ = λ/8.