dwdm spectrum

The explosive development of ip-based data Service brings unlimited demand for bandwidth, and dense wavelength division multiplexing (DWDM) system has incomparable networking advantages while satisfying the increasing bandwidth demand. In this paper, the key technologies are discussed. Key technologies of full optical networking for keywords dense wavelength division multiplexing (DWDM) WDM Optical Network

network equipment is mainly for TDM traffic, can only take advantage of the entire network of a part of the bandwidth, so once the user segment a large number of high-speed data access scheme (such as ADSL), will be due to the bandwidth convergence efficiency is very low or the application of excessive capacity of the transport backbone caused great pressure. At present, some operators are establishing and maintaining independent TDM, IP, ATM, Frame Relay network, resulting in a large amount of

) variables. The spatial domain is the coordinate system spanned by f (x, y) . The spectral components of the spectrum system in the four corners of the spectrum graph are obtained by 0. The discrete Fourier inverse transformation is given by the following formula:So that R and I represent the real and required parts of F respectively, then the Fourier spectrum,

China's LTE commercialization is approaching, and the industry's attention to the subsequent evolution of LTE has reached a new peak. Compared with 3G, LTE significantly improves the spectrum efficiency. However, the industry has not stopped. A few years ago, 3GPP began to research and develop the LTE-Advanced standard, and a series of technologies that can effectively improve the performance of existing LTE Networks emerged. Among them, the two most

layer, frame-based and VLAN-based access control, and RACL on the third layer;City Ethernet:A private VLAN is a Cisco proprietary technology. It is used to isolate hosts in the same VLAN. The management is complex and the scalability is poor;PVLAN can be divided into the primary VLAN and the secondary VLAN. The secondary VLAN can be divided into the isolated VLAN and the ac vlan;PVLAN port: public port, isolation port, and AC port. The isolation port can only communicate with public ports (only

Absrtact: This paper describes the colorful situation of optical network world, expounds the core technology of each series of optical Network, discusses the adaptation of optical network products to IP service, and puts forward the fusion node and intelligent Optical Network technology. Key words: Synchronous Digital Series SDH, digital cross connection equipment based on SDH s-dxc, dense wavelength division multiplexing DWDM, Optical Division multi

discrete signal is a continuous pulse, because the Fourier series coefficient of the discrete signal is cyclical, but continuous is not of this nature ); At last, continuous signals can only move the spectrum to a finite band, while discrete signals will continue to shift (however, in fact, the spectrum is 2 π, 4 π, 6 π, and so on, which is the same as 0, therefore, the low frequency is an even number of t

1: What are the characteristics of TDD technology? L Time Division Duplex (TDD): distinguishes uplink and downlink based on different time slots P advantages N when the upstream and downstream services are asymmetrical, different quantities of time slots can be flexibly allocated to the upstream and downstream operations, resulting in high spectrum efficiency. N uplink and downlink use the same frequency carrier, which facilitates the introduction of

Frequency-hopping spread spectrum; FHSS receives signals transmitted by narrow-frequency carriers of a specific type at both ends of synchronization and at the same time, for a non-specific receiver, the hop signal generated by FHSS is also called pulse noise. FHSS signals can be specially designed to avoid noise or non-repetitive channels of one-to-one channels, and these frequency hopping signals must comply with fcc requirements, the maximum interv

About DCT ......... MPEG adopts the Discrete Cosine Transform (DCT-Discrete Cosine Transform) compression algorithm proposed by Ahmed (a giant mathematician) in 1970s to reduce the spatial redundancy of video signals.DCT converts motion compensation errors or original image information blocks into coefficients that represent different frequency components. There are two advantages: first, signals usually focus most of their energy on a small range of frequency domains. In this way, desc

channel, so the interference between the signal waveforms can be greatly eliminated. In the OFDM system, the carriers of subchannels are orthogonal to each other, and their spectrum overlaps with each other. This not only reduces the mutual interference between subcarriers, but also improves the spectrum utilization. OFDM is a Multi-Car • rierModulation, MCM) Multi-carrier modulation technology. In some do

frequency w is divided into n parts, and the range of the entire digital frequency w covers the analog frequency range from the 0-2PI*FS. The FS here is the sampling frequency . And we usually only care about the spectrum in 0-pi, because according to Naikost law, only the signal within the F=FS/2 range is the valid signal that is sampled. So, in the range of W, the resulting spectrum is definitely about N

Guo Bin, Professor of the Department of television engineering, Beijing Broadcasting Institute 2) Two-Dimensional DCT MPEG adopts the discrete cosine transform (DCT-discrete cosine) proposed by Ahmed N. et al. in 1974.Transform compression algorithm to reduce the space redundancy of video signals (spatial)Redundancy ). Because static images and prediction error signals have very high spatial redundancy, the most widely used frequency domain decomposition technology to reduce spatial redundancy i

, which in the past two years has launched several rounds of tenders for td-lte equipment, and has opened a network of experiments in more than 10 cities in China. But even so, the 4G license plate guessing mystery or in the river of suspense tapered, the industry in addition to several operators and 4G standard back and forth to do radish and pit collocation, still did not give a convincing answer. The doubts about the Spectrum layout format October

, and some of the audio plus filters such as improve the tone (such as biquadfilternode), change the monotony, some audio segmentation, For example, the sound source in the channel segmentation to get the sound of the left and right channels (Channelsplitternode), some of the audio data spectrum analysis is used in this article (Analysernode). Audio API in the browserUnified PrefixThe processing of audio in JavaScript requires first instantiating

decompose the time domain signal into the sum of the sinusoidal signal or cosine function superposition of different frequencies. In continuous case, the original signal is required to satisfy the absolute integrable condition in one cycle. In discrete cases, the Fourier transform must exist. Gonzalez Fourier transforms have many excellent properties. such as linearity, symmetry (which can be used in the Fourier transform of the computed signal);Time-shift: The time shift of function in time do

Dense wavelength division multiplexing (DWDM) technology provides a huge transmission capacity for communication networks, and gradually becomes the mainstream transmission technology. With the maturation of DWDM technology and the rapid growth of transmission capacity, the pressure of traditional electronic switching system is increasing, and the introduction of optical switching technology is urgent. cor

user is serialized/transformed into multiple low-rate bitstreams, and each bitstream is sent using one subcarrier. OFDM does not use a band-pass filter to separate subcarriers, but uses the Fast Fourier Transform (FFT) to select waveforms that can maintain orthogonal even if they are overlapped. OFDM is a high-speed transmission technology in wireless environments. The frequency response curves of wireless channels are mostly non-flat, and the main idea of OFDM technology is to divide a given c

130 degrees, but only a central view of the 6~7度 in a small area to more clearly see the details of the object.In addition, the eye resolution ability and lighting environment has a great relationship, in the night when the lighting conditions are poor, the ability of the eyes to resolve greatly reduced, the minimum resolution angle of up to 1 degrees.There are about 100 different colors that people can tell. This single-wavelength shade is very vivid and is known as a solid color. Most of the

, it is not suitable for matrix switches because complex systems need to change the frequency to control switches. In addition, the table consumption of such switches varies greatly with the wavelength, and the driving circuit is also expensive. Another interesting switch uses MEM technology to adjust the beam in idle space. A variety of MEM switches have been developed that use different types of special low-light level devices activated by miniaturized mechanical systems. The worry of MEM swit