256 qam

Function Openjpgfile (FileName) Dim Ascii, Lasthex, Currenthex, Sosfound Dim FSO, File, I If Not FileName = "" Then If InStr (1, FileName, ": \") = 0 Then filename = Server.MapPath (filename) End If Set FSO = Server.CreateObject ("Scripting.FileSystemObject") If FSO. FileExists (FileName) Then Set File = FSO. OpenTextFile (FileName, ForReading, False, Tristatefalse) i = 0 While not file.atendofstream and Sosfound = False Ascii = ASC (File.read (1)) Lasthex = Currenthex Currenthex = Right ("

is the modulation method, because the frequency and bandwidth requirements for different applications are different. The DVB-S of high-frequency carrier is used to use the PSK modulation method, the DVB-C of low-frequency carrier is used to use the QAM-64 modulation method, and the DVB-T of high frequency carrier and ultra-high frequency carrier is used to use the coofdm modulation method. In addition to audio and video transmission, DVB also define

communication receiving and sending machine, because the result of using the Sinc Function orthogonal is the best spectrum efficiency (although the method of suppressing bandwidth can suppress the out-of-band sides of each sub-band, it will lead to the continuation of time domain signals, which causes inter-symbol interference ). Orthogonal Frequency Division Multiplexing (OFDM) builds a high-performance, low-complexity transceiver based on orthogonal characteristics between discrete frequency

the 249 MHz band and is divided into 25 uplink channels and downlink channels in a 4 kHz width. The input data is transmitted to the subchannel after being encoded by TCM and modulated by QAM, therefore, theoretically, the uplink speed can reach 1.5 Mbps and the downlink speed can reach 14.9 Mbps. Considering interference, the actual transmission rate is generally 640 Kbps and 8 Mbps. We usually download about 250 Kbyte at the actual rate of 2 m ADSL

a waveform (high-order modulation). So there is a question that I do not know 0 corresponds to what waveform, 1 corresponds to what waveform, is because did not understand the modulation process.after using such as QAM64 modulation, the symbol that comes out is plural., which is also the origin of the plural signal. The general article treats a symbol as an input and discusses the following steps, and I'm going to talk about orthogonality from sin and cos, so I see a symbol as two real numbers

supports multiple European languages and hybrid display of simple images and texts. Chapter 2 Composition of the DVB System[This article does not describe the hardware structure of the DVB system in detail, but explains in detail the format and Reuse Principle of the TS code stream according to the description in iso13818. (Enough, Enough)]Classification of DVBAccording to the application of different DVB, mainly divided into DVB-S, DVB-C, DVB-T, DVB-H and other specifications. Different Specif

construction include class style, functional requirements for value-based Student Management, class honors, student works, student centers, etc. Xinyi aojiashi Electronics Co., Ltd. was established in 2012. It specializes in the production of Cable Digital TV front-end products and undertakes cable TV iptv system smart interactive TV solution design and digital TV transformation project.I. okasi digital TV front-end products include the following four categories:1. Analog Front-end: modulated d

Cable technology and RF technology, therefore, analog TV signals and digital signals are transmitted simultaneously between 5-MHz, and 64QAM (orthogonal Amplitude Modulation) technology with commercial efficiency is used, the downstream channel speed can be up to 30 Mbit/d. The transmission rate of Cable Modem has nothing to do with the distance of transmission, but it is related to the noise of the optical fiber and the number of users of simultaneous broadband access technology. ADSL divides

experience, the disadvantages of these technologies always affect the implementation of the broadband access network technology. For example, although the unit cost of Ethernet technology is low, the cost of Ethernet technology is quite high and the initial investment is too large when there are few users, other problems, such as network management and IDC environment, are also very serious restrictions. According to the characteristics of China, at present, Heli Jinqiao Company in China launch

the application of analog and digital transmission technology, fiber-optic coaxial Cable technology and RF technology, therefore, analog TV signals and digital signals are transmitted simultaneously between 5-MHz, and 64QAM (orthogonal Amplitude Modulation) technology with commercial efficiency is used, the downstream channel speed can be up to 30 Mbit/d. The transmission rate of Cable Modem is independent of the transmission distance, and is related to the noise of the optical fiber and the nu

Wireless network technology is becoming more and more powerful. to master the RF communication technology, we will give you a detailed description of the wireless technology, suppliers are attempting to use "easy to install", "seamless connection" and other commitments to mask abnormal Wi-Fi physical layer signals. However, you need to use RF technology to manage a large wireless network, just as you must know that if the connection is used to build an effective lan. Knowledge of RF communicatio

This paper examines the principles of Nyquist and Shannon's theorem, which is the theory of communication engineering. Nyquist: In the absence of noise, the relationship between the code element rate limit B and the channel bandwidth: b=2*h (Baud) Nyquist formula----Noise-free channel transmission capacity formula:c=2*h*log2n (bps)H is the channel bandwidth, in the subject h=3khz n is the number of discrete values obtained for a code element, in which the n=16 (4 phases, the amplitude of each ph

the tuning demodulator constitutes a different digital set-top box, for example, the satellite set-top box (dvb-s) for QPSK demodulation, A wired digital set-top box (dvb-c) for QAM demodulation and a terrestrial transmission digital set-top box (DVB-T) for OFDM demodulation. At present, the market is more popular tuning demodulator manufacturers have Thomson, Sharp, and so on, although some manufacturers in the domestic production of tuning demodula

fill. DirectoryChapter One physical layerChapter II Data Link LayerChapter III Network layerFourth transmission layerFifth application layer (temporary space)The sixth chapter related nounThe seventh chapter of the computer network in lifeThe eighth chapter analysis Chapter One physical layerPhysical Layer Overview: Each layer has a responsibility for each layer, the physical layer of the overview is: How to send? How to collect? 2 The primary task of the physical layer is descr

testThe significance test of the so-called regression coefficient is the test hypothesis H0:bj=0, ...,m). under the conditions of the establishment of H0, there are:tj= b~j/(cjja~) ^ (a) ~ T (n-m-1)which CJJ is the first J+1 element on the main diagonal of the c= (xTx) 1 . For a given significance level, the value of Tj is computed and the table is judged to accept or reject H0. 2. the significance of regression equation testthe significance test of regression equation is about H0:b0=b1= ... =

Problem:1. Resource particle Re, used (k,l) to identify the coordinates of the time domain in the frequency domain, how to understand. A: K is the number of the sub-carrier of the resource raster, L is the SC-FDMA ordinal in the time slot 2. A RB has n time-domain continuous SC-FDMA symbols and a continuous sub-carrier composition in the frequency domain. What a SC-FDMA symbol refers to. is the number 0 or 1. or a modulator (for example, 8-in modulation, 8-frequency shift keying, this symbol is

Shanghai Bell Company's Cablelink Cable modem system provides high-speed asymmetric data communication services to users through the fiber coaxial hybrid network. The asymmetry of its connections requires high-speed communications in one direction, such as network browsing, Internet file transfer, and ideally in the opposite direction with a lower-rate delivery service. The TDMA access method used in Cablelink 2000 system can make the system more flexible when it is enlarged. On the front end, t

like this:0.299=299/1000=1224/4096So D = (R * 1224)/4096Y= (r*1224)/4096+ (g*2404)/4096+ (b*467)/4096Then simplify to:y= (r*1224+g*2404+b*467)/4096Here the /4096 division, because it is 2 of the N-square , so can be replaced with a shift operation, to the right shift 12bit is to divide a number divided by 4096.void Calc_lum (){int i;for (i = 0; i {int r,g,b,y;R = 1224 * IN[I].R;g = 2404 * IN[I].G;b = 467 * IN[I].B;y = r + G + B;y = y >> 12;//This removes the division operationOut[i] = y;}}This

Transferred from: http://netsecurity.51cto.com/art/201301/378513.htm1. IntroductionOpenSSL is a powerful cryptographic toolkit. Many of us already use OpenSSL to create RSA private keys or certificate signing requests (CSRs). But have you ever known that you can use OpenSSL to test your computer's speed? Or can you use it to encrypt a file or a message? This article will show you a few easy-to-learn tips on how to encrypt messages and files using OpenSSL."Related recommendations": network Securi

of the texture must be a power of 2. Format: Specifies the formatting of the pixel data and must be the same as the internal format. Type: Specifies the data type of the pixel data, in this case, using the RGB565 (16-bit) format. Pixels: A pointer to an in-memory image data that must be encoded using RGR656. Note: The size of the texture must be a power of 2, such as 256, 512, 1024, and so on. However, the size of the video image to be displayed can