Hello there! I have a problem with conteptual understanding of the bandwith od channels that use frequency division multiplexing. How i understand that FDM works: We have a transmitter that transmits on one frequency f and the receiver that listens on that frequency. They can communicate becouse the frequency is the same. That frequency in a spectral diagram looks like a vertical line at f. It is common ito draw FDM in spectral diagrams as areas representing a range between frequencies [f-fr,f+fr]. The size of fr are ussualy very small a percent of f , so i interprete them as tolerance in a way that a receiver would detect a frequency at f+fr just the same as f. The problem arises when the bandwith are drawn as wide areas on the spectrum graph (like in DSSS - Direct sequence spread spectrum) like in the picture here What does that imply on the side of modulators? That they have to have thousands of modulators to cover a bandwith of couple of MHz at the same time?