dqpsk modulation

Ps:http://www.telecomhall.com/what-is-ecio-and-ebno.aspxIf someone asks "which Signal level for good call quality: -80 dbm or-90 dbm?"Beware, if you respond quickly, you might end up missing. This was because the correct answer is ... it depends! The Signal strength is a very important and essential measure for any technology (GSM, CDMA, UMTS, LTE, etc). However, it isn't the only One:let's talk a little today about another magnitude, equally important:the Signal Noise Ra Tio.Although this ratio

Forum post Serial-The principle of communication is relatively good technology paste, address http://bbs.c114.net/forum.php?mod=viewthreadtid=394879page=0Excerpt a few of the more rewarding parts.1 The author proves that convolution actually represents the coefficients after the multiplication of two polynomial, if the signal can be expressed in the form of a polynomial, then the multiplication of the signal can actually be expressed as the coefficient convolution of the polynomial. Can you do t

The training and 2015 National Electronic Design competition is over.Many things were learned during the training period.Just started to use 2sc3355 to do 1.4GHz RF amplifier, using Microstrip line to do transmission line, on the Vector Network Analyzer to observe the parameters such as S11,S12,S21,S22. The amplifier effect is not very good. This and the circuit layout and general capacitance inductance in the high-frequency characteristics of the changes have a great relationship.Next, the FM t

values and engineering achievable values for modulation, demodulation, error correction, reception sensitivity and spectral efficiency. Different modulation methods generally correspond to different error correction methods, in the wireless communication system, the error correction performance will directly affect the overall performance of the system, especially in the organization of multi-sector more t

the configurations has similar responses to input levels, and that the 2N3904 Have a bit less offset, as you would expect Fromfigure 2. The output can drive a signal level meter or following electronics as part of an Automatic-level-control or Automatic-gain -control Loop. the transfer function Infigure 1also shows a sudden increase in inverted current at app Roximately 7.6V, which occurs at the reverse breakdown voltage for the emitter-to-base junction. Because you know in the "the" the base i

: frame, ether frame, Ethernet frame Network layer: IP datagram Transport Layer: TCP segment, TCP message segment Unidirectional communication (simplex) [can only be sent], bi-directional alternating communication (half-duplex communication) [cannot simultaneously receive \ Send], two-way simultaneous communication (full-duplex communication) [may simultaneously receive, send] Baseband signal: Data signals such as text and images are baseband signals Band-Pass signa

standard bluetooth technology uses 79 data channels ). Another reason for requiring the Bluetooth Low-energy technology to enable wireless connection for the shortest time is that it has 1 Mbps of original data bandwidth-a larger bandwidth allows more information to be sent in a shorter period of time. For example, another wireless technology with kbps bandwidth needs to be enabled eight times (consuming more battery energy) to send the same information ). Bluetooth Low-energy technology "Compl

); % calculates the new coordinates generated by the Gabor function rotationX=tpx*cos (theta) +tpy*sin (theta);Y=-tpx*sin (theta) +tpy*cos (theta); % calculation Gauss functionz=1/(2*pi*sigmax*sigmay) *exp ( -0.5* (X/sigmax). ^2+ (Y/sigmay). ^2)); % calculated modulation factorExptab=exp (-j2*pi* (TPX*MU+TPY*MV)/n); %gauss function modulated by modulation factorHp=z.*exptab; % matrix transpose to generate X

I. The concept of PWM and duty-free ratio ①PWM: Also known as pulse width modulation technology, is an analog control mode, the PWM waveform as shown below. ② duty cycle: refers to the proportion of the high level in a period. For example, a duty cycle of 50% means that the high level accounts for half of the period. Two, PWM fixed frequency speed regulation principle In the PWM speed regulation system, it is generally possible to change the dut

Cable Modem is developed in recent years, mainly for CATV network data transmission. Most new cable networks now use fiber-optic coaxial hybrid (HFC) networks, and their huge bandwidth and relative economics make them attractive to cable companies and newly established telecoms companies. Because cable modem is a kind of equipment that provides data service on HFC network, it is usually equated with HFC broadband access technology. Using 64QAM technology, Cable Modem can provide 30mbit/s downli

receiver can be from all other signals from the background to restore the original information code (this process is called the extension). CDMA can be divided into direct sequence spread spectrum (DS), FH (FH) and Hop Time (TH) According to the modulation method of obtaining bandwidth signal, as shown in Figure 2 below: 2 Rake Receiver Rake receiver is also known as Multipath receiver, that is, mobile Taichung has multiple rake receivers, because

junction unit, ceramic head connection should ensure that each connection point attenuation is not less than 0.4dB. The connector of the plastic head has a attenuation of less than 0.5dB for each connection point. Integrated wiring system should adopt optical fiber diameter 62.5μm fiber cladding diameter 125μm of slow-change enhanced multimode fiber optic cable, nominal wavelength of 850nm or 1300nm, also can use nominal wavelength of 1310nm or 1550nm single-mode optical cable. The digital se

WiMAX can be considered as an alternative to some DSL or cable access modes; For some temporary gatherings, such as exhibitions and sports venues, WiMAX has the flexibility to deploy quickly, which is especially suitable for future applications in Olympic projects, and the WiMAX deployment cycle features a shorter and more flexible approach than DSL or cable access. Point to point Wireless broadband access Point-to-Point wireless broadband access is mainly used in point-to-point mode for wire

After reasonable management, two kinds of distortion factors (dispersion and self phase modulation) in optical fiber can cancel each other, so that the optical soliton can play its role. The color closing causes the pulse signal containing a group of wavelengths to diverge gradually with the increase of the transmission distance. Self-phase modulation (SPM) spreads the spectrum of light pulses horizontally.

the development of CDMA2000 standards, has been fully considered to protect the operator's investment, many wireless indicators in the 2G and 3G are the same. For BTS, RF parts such as antennas, RF filters and power amplifiers can be the same, while baseband signal processing must be replaced. Second, the main characteristics of CDMA2000 1X The main difference between the CDMA2000 and the IS-95 system is that the channel type and the modulation of

Electrical signals (that is, the full-TV signal we need to modulate) it is a fixed frequency that is set by the state, that is, the total source of the signal we want to modulate. From electrical signals to light signals: the popular understanding is to be modulated by the signal loaded into the light-emitting diode, with its strong and weak changes to control the luminous intensity of the light-emitting diode changes, and then by the same module of the photosensitive transistor received by some

networkThe input of a double-tuned merge network must be a double-tone sequence. If you want to turn it into a sort network for any input sequence, you first need to convert the input sequence to a double-tone sequence. The main idea is: the sequence of length 2n is regarded as an ordered sequence of n 2 elements, and any two ordered sequence can be composed of a 4-element double-modulation sequence, then a double-

each channel (8 MHz) is time-division multiplexing transmission, the channels are still transmitted in frequency-division multiplexing mode. 1.2 orthogonal frequency division multiplexing Orthogonal Frequency Division Multiplexing is a multi-carrier digital modulation technique. All OFDM carrier frequencies have equal frequency intervals, which are an integer multiple of the basic oscillation frequencies. Orthogonal means that the signal spectrum of

volume is small or there is no business. Multi-line rate bundling is supported, it can achieve a higher data rate. It is worth noting that although the new-generation ADSL technology has introduced the ADSL2 and ADSL2 + standards, the ADSL2 standard only paves the way for the final launch of the ADSL2 + standard, the new-generation ADSL technology will be promoted and applied in the form of ADSL2 + technology. VDSL technology has always been a controversial technology. Its standard trend and it

audio and data transmission standards. LMDS work in millimeter bands, 20 GHz ~ For 40 GHz frequencies, the licensed frequencies are 24 GHz, 28 GHz, 31 GHz, and 38 GHz. Among them, 28 GHz has more licenses, and the frequency band has a relatively loose spectrum range, it has the potential to provide multiple services. Currently, the fixed broadband wireless access system uses three types of air interfaces: IP address-based, ATM cell-based, and TDMA-based time slot allocation. It has a theoretica