Baseband and broadband transmission are ways in which digital signals can be transmitted from one point to another.
Baseband transmission refers to transmission in which a digital signal is sent over a channel without changing or converting the digital signal to an analog signal.
Broadband transmission sometimes referred to as modulation means changing or converting a digital signal to analog signal for transmission.
The conversion from digital to analog is possible with modulation.
One factor that determines if a signal needs to be transmitted as baseband or broadband is the bandwidth.
In baseband transmission, the required bandwidth is proportional to the bit rate; if we need to send bits faster, we need more bandwidth.
Baseband transmission requires that we have a low-pass channel, a channel with a bandwidth that starts from zero while Broadband transmission requires that a bandpass channel and only an analog signal can be transmitted.
A bandpass channel is a channel with a bandwidth that does not start from zero and it is limited.
In conclusion, in baseband transmission a digital signal can be directly transmitted through a channel while in broadband transmission the digital signal cannot be transmitted directly so it is first converted to an analog signal before transmission.
📖 Data Communications and Networking by Behrouz A. Forouzan