In communication systems, what is the primary role of a multiplexer?

The primary role of a multiplexer in communication systems is to combine multiple signals into one for transmission. A multiplexer allows multiple input signals to be channeled through a single output line while maintaining the integrity of each individual signal. This is particularly useful in communication systems because it optimizes the bandwidth usage by minimizing the number of physical channels needed for communication, enabling more efficient transmission of data.

In contrast, the other choices describe functions that are not the primary purpose of a multiplexer. For instance, measuring the strength of radio signals pertains to signal evaluation rather than management. Sending a single signal over multiple channels simultaneously involves different technology, namely a demultiplexer, which operates in coordination with multiplexers but serves a different function. Lastly, converting audio signals into radio frequencies is a function associated with modulation techniques and not the operation of a multiplexer.