Modulator is a machine or software that could transform channel code words to a corresponding analogue symbol. For example, the symbol could be into waveform when there is a need to travel in Fibre-Optic Cable.
At the receiver side, Modulator will act as a Demodulator, where it transforms the analogue symbol into estimated channel code words and pass it to #Channel Encoder.
SONET is a #Physical Layer #optical technology that supports from 155 Mbps up to 10 Gbps high transmission rates for Metropolitan Area Network (MAN) using #Time-Division Multiplexing (TDM) multiplexing scheme. It provides means of transportation to Data Link Layer# protocols and of conversion using Fibre-Optic Transmission Systems (FOTS), which is a Modulator. It has extensive OAMP (operation, administrative, maintenance and provisioning) capabilities. This allows precise fault detection and a rapid (50 ms) failover (switching to a redundant or standby computer server, system, hardware component or network upon the failure or abnormal termination of the previously active application). Its speed is range from 51.84 Mbps (OC-1) to 9953.28 Mbps (OC-192).
DPT is an #optical networking technology that utilises SONET/SDH framing and employs intelligent protection switching in the event of fibre facility or node failure or signal degradation. Electrical signals and light can be converted to each other form via Fibre-Optic Transmission Systems (FOTS), whihc is a Modulator. It uses a bidirectional, counterrotating ring structure for metro applications, and a star structure with a central switching device for service point-to-point backbones.
DWDM uses the same #multiplexing technique as Coarse Wavelength Division Multiplexing (CWDM). However, compare to CWDM ability to multiplex 8 signals, DWDM system is able to multiplex 32 signals into a single fibre. Additionally, the signals can be amplified, making them keen to be transmitted up to 250 km. The conversion between electrical signals and light are done by Fibre-Optic Transmission Systems (FOTS), which is a Modulator.
Channel Encoder is a machine or software responsible for adding redundant bits to #source code words in order to transform them into channel code words which could be reliably transmitted in a potential noisy channel. It will usually proceed to Modulator#.