What is the difference between FDM and TDM?

Two common methods of multiplexing are TDM or Time Division Multiplexing and FDM or Frequency Division Multiplexing. By multiplexing, it means the process of sending multiple signals via a data link. One of the major differences between TDM and FDM is that the former uses time slots to allocate specified time frames for each signal, while the latter uses different frequencies for each signal coming from different devices.

Unlike TDM that can be used for both analog and digital signals, FDM can only be used for analog signals. This explains while TDM is usually preferred to FDM. In order to ensure synchronization, TDM uses framing bits. In contrast, to prevent overlapping, FDM uses guard bands to divide the signals.

The different carriers generated by the FDM system for different channels use different frequency bands. Another difference is that time division multiplexing requires fewer circuits compared to Frequency Division Multiplexing.

FDM and TDM are two terms related to data communication. FDM stands for Frequency Division Multiplexing. In FDM a channel is divided into two frequency ranges or even more. These ranges will not overlap. TDM stands for Time Division Multiplexing.

It differs from FDM because it will divide the channel and then give each signal a specific time period. With the specific time period that each channel has, it is easier to give more time to the signals, depending on the amount of bandwidth that each signal uses. Due to this, TDM is more efficient and more flexible. Another difference between them is in regards to latency, which TDM will have less.

Although, FDM or Frequency Division Multiplexing and TDM or Time Division Multiplexing are two ways of combining multiple signals into one, there are still some little differences between the two, especially when you compare the mechanism employed into the two. How the two methods divide the channel is one of the major differences between them. With FDM, the channel will first divide into two or more frequency ranges and they will not overlap.

In contrast, TDM will first divide the channel and give specified time periods to all signals. Since each channel has a specified time period, it is very easy to allocate more time to the signals that use more bandwidth. This will not only improve efficiency and flexibility, but it will also stop the allocation of more time to the signals that need less bandwidth. Another difference between the two which also doubles as the advantage of FDM over TDM is that the former has lower latency than the latter.