In TDM, the transmission rate of a multiplexed path is always the sum of the transmission rates of the signal sources.

In Time Division Multiplexing (TDM), the transmission rate of the multiplexed path is typically higher than the sum of the individual transmission rates of the signal sources. This is because TDM involves allocating distinct time slots to each signal source within a single transmission channel. However, it’s important to account for the fact that the total throughput must accommodate not only the data from the individual sources but also any additional bits needed for synchronization or to delineate the separate time slots.

Thus, the multiplexed path’s transmission rate must be high enough to carry the combined data rates of all signal sources plus any overhead introduced by the multiplexing process itself. The statement provided suggests an ideal scenario where the overhead is minimal or nonexistent, which is not always the case in practical applications. Indeed, in a perfectly efficient system, the statement could be seen as conceptually accurate, but in real systems, the total transmission rate will also include additional bits for framing, synchronization, or error checking, depending on the specific type of TDM and the protocols used.