Question

The device which works for both modulation and demodulation is called:

• A. Laser
• B. Radar
• C. Modem
• D. Fax

Hint:

Modem = Modulator + Demodulator.

Answer 1

The Correct Option is C

A modem, short for modulator-demodulator, is an essential device in communication systems that enables the transmission of digital data over analog communication channels, such as telephone lines. The process involves two main functions:

Modulation: The modem converts digital signals generated by a computer or other digital device into analog signals suitable for transmission over analog media. This is necessary because traditional telephone lines and many communication channels are designed to carry analog signals, not digital pulses. The modulation process typically involves varying a carrier wave's properties—such as amplitude, frequency, or phase—according to the digital data.
Demodulation: Upon receiving the analog signals, the modem performs the reverse operation, converting the analog signals back into digital data that the computer or receiving device can interpret. This ensures that the transmitted information can be correctly recovered and processed.
By performing these dual roles, the modem acts as a bridge between digital devices and analog communication infrastructure, allowing seamless digital communication over channels that would otherwise be incompatible with digital signals. This capability is crucial for internet access via telephone lines, fax machines, and other data communication applications.