What does Baseband transmission refer to?

Baseband transmission refers specifically to the method of sending a single data signal over a medium without modulation. This means that the entire bandwidth of the transmission medium is utilized to transmit one signal at a time. In baseband transmission, the signal is typically in its original digital form, which is directly transmitted as electrical pulses over a cable or fiber optic medium without being converted to different frequencies.

This method is commonly used in local area networks (LANs) where a single channel carries digital signals, allowing for more efficient and straightforward communication. It contrasts with techniques that involve the simultaneous transmission of multiple signals or the modulation of signals onto different frequencies, which would not fall under the definition of baseband transmission. Thus, the correct choice accurately describes the essence of baseband transmission by emphasizing its focus on a single data signal being transmitted directly.