What components transmit communication signals through transmission lines?

Coupling capacitors play a critical role in the transmission of communication signals through transmission lines. Their primary function is to allow alternating current (AC) signals to pass while blocking direct current (DC) signals. This characteristic is essential in communication systems, where AC signals carry the information, and DC voltages generally need to be isolated to prevent interference and ensure signal integrity.

In addition to allowing AC signals to propagate, coupling capacitors help to prevent loading effects on the source and load circuits, maintaining the strength of the transmitted signal. They also play a role in filtering out unwanted noise and ensuring that only the desired frequency components are transmitted along the lines.

By effectively coupling the stages of a communication system, these capacitors ensure that signals can be transmitted over distances without significant loss or distortion, making them vital for efficient communication. This function distinguishes coupling capacitors from other components listed, which do not specifically focus on signal transmission through coupling in communication networks.