In signal communication, in addition to baseband communication, there is also a part of band pass modulation that achieves maximum utilization of the transmission medium through modulation and demodulation technology. During wired transmission solutions, common technologies include Frequency Division Multiplexing, Time Division Multiplexing, and Wavelength Division Multiplexing. The following is the analysis of their characteristics and principles:

Frequency Division Multiplexing

In the same communication line, different channels are automatically divided, and communication data packets can be divided according to frequency and transmitted into different channels, achieving the transmission of more data packets in one communication line. Cable types: two core copper wire, twisted pair, coaxial cable, etc. Modulation equipments: Ethernet Extender (OFDM), Network Extender (VDSL2), Power Line Extender (PLC), and Dial-up Modem.

Time Division Multiplexing

On the same channel, transmitting multiple signals simultaneously, unlike frequency division vertical transmission, time division multiplexing arranges multiple signals horizontally and synchronously modulates them in chronological order. Optical Time Division Multiplexing (OTDM) is quite common in practical communication, using optical fiber and optical modules. This technology can greatly improve the communication capability of optical fiber.

Wavelength Division Multiplexing

It refers to frequency division multiplexing of optical fiber. Use a single fiber to simultaneously transmit multiple optical carrier signals of different wavelengths.

These modulation methods each have their own advantages and disadvantages, and cannot be compared one-sidedly. In communication, their advantages should be utilized to form a more efficient network.