Electrical Engineering XYZ MCQs
Which of the following is not a transmission medium:
- Modem
- Telephone lines
- Microwave systems
- Coaxial cables
Correct answer: 1. Modem
Explanation: A modem (modulator-demodulator) is not a transmission medium but a device that modulates and demodulates digital data to enable communication between digital devices over analog transmission lines. It is used to convert digital signals from a computer into analog signals for transmission over telephone lines and vice versa.
On the other hand, the other options are all examples of transmission mediums:
- Telephone lines: These are physical communication lines that can transmit analog signals (as in traditional voice calls) or digital signals (as in digital communication).
- Microwave systems: These involve the use of microwave frequencies to transmit signals through the air, often used in point-to-point communication for long-distance links.
- Coaxial cables: These are physical cables that consist of a center conductor surrounded by insulation and then a metallic shield, used for transmitting electrical signals, including television signals and internet data.