What is the difference between fdm and wdm

If you want more information please let me know through comments in the right below. Subscribed to the My Computer Tutors for updates. I will keep updating you with the latest tutorials. Email This BlogThis! Share to Twitter Share to Facebook. Subscribe to: Post Comments Atom. Popular Posts. Functional Components of a Computer. Computer system made up of a combination of hardware and software, both are an integral part to use the computer.

Today in this section we a Storage Devices of Computer. Hello friends in this session we are discussing the storage devices also called as secondary memory. Memory is the most essential part of Hello friends, today we are going to see the internal architecture. In this type of multiplexing, every subchannel is having its own frequency band, which is the reason technology is called frequency division multiplexing. Each subchannel has been modulated with different frequencies before being multiplexed to the single channel.

It allows usage of single line for up to 24 telephone users instead of making separate line to each residence. Technology allows demultiplexing signal at the receivers end. Roderick Mason. Yet No Comments. Difference Between Dumplings and Wontons Wontons. Difference Between Gunshots and Fireworks Sound. Matthew Goodwin. Difference Between Prairie and Plain Prairie. Thus multiple signals are transmitted simultaneously over a single communication channel.

Wavelength division multiplexing is a technology that increases the bandwidth of a communication channel optical fiber by simultaneously allowing multiple optical signals through it. In wavelength division multiplexing, the communication channel is a fiber optic cable. Wavelength division multiplexing is also known as WDM. A demultiplexer at the receiver end separates the optical signal wavelengths or colors. The wavelength division multiplexing divides the bandwidth of a channel into several logical sub-channels according to its wavelength.

It allots each logical sub-channel for a different light color or optical signal wavelength. The individual signals are filtered and then modulated wavelength is shifted , to fit exactly into logical sub-channels.

In this technique, each logical sub-channel individual signal wavelength is allotted to each user. The main advantage of WDM system is that you only need to upgrade the multiplexer and demultiplexer at each end; you no need to buy more fibers which are more expensive.

Wavelength division multiplexing enables bi-directional communication and multiplication of optical signal capacity. The schematic diagram of a WDM system is shown in the below figure. The transmitter end contains multiple optical transmitters and the receiver end contains multiple optical receivers. The communication channel optical fiber is present between the transmitter and receiver. At transmitter end, each transmitter sends an optical signal of different wavelength or color.

These optical signals of different wavelengths or colors are then multiplexed or combined by using a device called multiplexer. The multiplexed signals are then transmitted over a single communication channel optical fiber.

In between the transmitter and receiver, optical amplifiers are used to compensate the optical signal loss caused during the transmission. The separated signals are then sent to the respective receivers. WDM techniques are of two types:. It is a technology in which a large number of optical signals laser light of different wavelengths or colors are combined into one signal and is transmitted over the communication channel to a long distance.

When the optical signal transmission distance becomes hundreds of kilometers, some signal loss will occur. In order to compensate this signal loss, optical fiber amplifiers are used in the DWDM communication system. However, these amplifiers will not work effectively in the entire bandwidth of the communication channel.

They work effectively in a small wavelength range. This small wavelength range is called gain bandwidth. Therefore, very small wavelength spacing is needed between two optical signals to put a large number of optical signals into the gain bandwidth. The DWDM technology uses this gain bandwidth to effectively transmit a large number of optical signals simultaneously.

Coarse wavelength division multiplexing is a technology in which multiple optical signals laser light of different wavelengths or colors are combined into one signal and is transmitted over the communication channel for a short distance. Coarse wavelength division multiplexing is also simply referred to as CWDM.

However, if the transmission distance is less than kilometers, we no need to use optical amplifiers. Hence, gain bandwidth is not required. We can send optical signals in the entire bandwidth of the communication channel. This allows the wider channel spacing between the optical signals. A typical CWDM system has a channel spacing of 20 nm between the optical signals.

Coarse Wavelength Division Multiplexing has the ability to transport up to 18 optical signals per optical fiber. It is designed for short distance. WDM allows transmission of data in two directions simultaneously. Greater transmission capacity. High security. Long distance communication with low signal loss. The process of combining multiple digital signals into one signal is called digital multiplexing. Time Division Multiplexing is a technique in which multiple signals are combined and transmitted one after another on the same communication channel.

At the receiver side, the signals are separated and received. Each signal is received by a user at a different time. It is the digital multiplexing technique.