Construction Coordinator Practice Exam

What happens to the signal tapped off from the input in a directional coupler?

1. It is amplified

2. It experiences insertion loss

3. It is entirely blocked

4. It is redirected to a different channel

The correct answer is: It experiences insertion loss

In a directional coupler, the signal tapped off from the input experiences insertion loss. This loss occurs because the directional coupler is designed to divide the input signal between its output ports and a portion of the input signal is used for the coupling process. The purpose of the coupler is to allow a predetermined amount of the input signal to pass through to one output while directing another portion to a different output. The concept of insertion loss refers to the reduction in signal power resulting from the insertion of the coupler into the transmission path. This loss is a natural characteristic of passive devices like couplers, which cannot operate without affecting the original signal's strength or quality due to the inherent resistive components and energy coupling processes involved. It’s important to note that while the coupler does redistribute the signal, it does not amplify it or entirely block it; rather, it splits the input signal, with a portion of it being lost as insertion loss. Therefore, understanding that insertion loss is an expected consequence in the operation of a directional coupler is key in designing and analyzing RF and microwave systems.