Which of the following is not listed as one of the receiver’s five fundamental functions?

• A. Apodization
• B. Amplification
• C. Compensation
• D. Rejection

Answer: (A)

The receiver’s main duties are to boost weak echoes, correct for depth-related signal loss, compress the wide dynamic range into something displayable, extract the signal envelope, and suppress unwanted noise. Apodization is a beamforming technique used to shape the excitation of array elements to reduce sidelobes, and it sits with transmit/beamforming control rather than as a fundamental function of the receiver itself. Because of that, it isn’t listed among the five core receiver functions. The remaining functions—amplification, compensation, compression, demodulation, and rejection—are the established five, making apodization the best answer for what isn’t a fundamental receiver function.