What is the primary role of an amplifier in a communication system?

The primary role of an amplifier in a communication system is to boost RF (Radio Frequency) signal levels. Amplifiers are essential components that increase the power of a signal, whether it be in a transmission or reception stage. By raising the signal strength, they help overcome losses incurred during signal propagation through cables or air, ensuring that the signal reaches its intended destination with sufficient clarity and power. This enhancement is crucial in maintaining signal integrity and improving overall system performance, particularly in scenarios where the distance between transmitting and receiving equipment is significant or when there are potential obstructions that could weaken the signal.

While other functions like converting signals from digital to analog, modulating signals, and filtering out unwanted frequencies are important in communication systems, they are not the primary function of an amplifier. Instead, these tasks are typically handled by other specialized devices or components in the system. Thus, the defining functional characteristic of an amplifier is its capacity to amplify signals, making option B the correct choice.