Baseband is associated with digital signal transmission, where the entire bandwidth of the baseband system transmits only one data signal at a time. In other words, each signal requires exclusive use of the shared medium. When I use this medium, no one else can use it. They must wait their turn. Ethernet is an example of a baseband system. Regardless of the different versions, whether it's early Ethernet, Fast Ethernet, or 10 Gigabit Ethernet, they all contain the word "baseband". They are all baseband. 

Baseband also refers to the original frequency range of an analog signal before it is modulated to a different frequency range. An audio signal may have a baseband range of 20 to 20,000 Hz. When it is transmitted on radio frequencies (FR), it is modulated to a much higher frequency range. AM and FM are two comma modulation techniques used in radio broadcasting.

The term "broadband" technically refers to any signal transmission technique that carries two or more different types of data in separate channels. Broadband signals can share one medium. It's like a multi-lane highway. Two or three cars can share the highway side-by-side.

Broadband is also used as a marketing term for Internet access. This meaning is only distantly related to its original technical meaning. In widespread use, broadband Internet refers to any high-speed Internet connection such as DSL, cellular, cable modem, or satellite.

In short, baseband relates to digital signals, while broadband relates to analog signals. Baseband systems do not allow digital signals to share one medium at the same time, while broadband systems can transmit different data side-by-side simultaneously. However, baseband transmission can have bi-directional data flow; it can send or receive data on the same wire medium, similar to coaxial cable. In a broadband system, each channel's signal is transmitted in only one direction. We must use different separate frequency channels to send or receive data.

For analog signals, frequency division multiplexing (FDM) is used to enable analog signals to share a common medium. For digital signals in baseband systems, time division multiplexing (TDM) is used to transmit different data uses on a common medium. TDM divides time into slots or intervals and distributes them equally among users. In this way, each one has an equal share. In general, baseband systems transmit less data than broadband systems.