2.13. Multichannel Transmission Techniques

In applications like television transmission many analog signals are to be sent over the same fiber. To do this a multiplexing technique has to be used where a number of baseband signals are super imposed electronically on a set of N subcarriers that have different frequencies f1,f2, f3….fN. These modulated subcarriers are then combined electrically through Frequency Division Multiplexing to form a composite signal that directly modulates a single optical source. Methods for this include vestigial sideband amplitude modulation (VSB-AM), FM and SCM.