pam4 modulation

technology in the OSI 7-layer model. The complexity of this technology lies in that you must first establish the electrical characteristics of the transmission media, generally, different transmission media have different processing capabilities for signals in different frequency segments. The ethernet cable processes the baseband signal, and the wide area network light emits high-frequency modulation signals. Mobile Communication, 2G and 3G require

characteristics of high voltage regulation precision, no use of power transformers, etc, it is an ideal regulated power supply. Because of this, switching type regulated power supply has been widely used in a variety of electronic equipment, this paper describes the working principle of various types of switching power supply.I. basic working principle of On/Off regulated power supplySwitch-type regulated power supply control methods are divided into two types: Width Adjustment and frequency

of the satellite Main Station and the satellite forwarder after the frequency division or time division modulation, the user receives data through the satellite antenna and satellite Modem, and the receiving antenna is generally 0.53 m or m in diameter. Because the digital satellite system has high reliability, it does not require much signal correction for analog phones using twisted pair wires in the PSTN network. Therefore, the download rate can r

. Compared with single-carrier technology with the same data rate, OFDM signals have a longer symbol period, this technology has a strong performance against multi-path fading. In addition, the modulation methods used on the carrier are BPSK, PSK, 16QAM, and 64QAM. Various Modulation Algorithms are automatically switched according to the transmission rate requirements. Compared with WLan, WiMAX signal bandw

that the generated waveform occupies the bandwidth of several GHz. The wireless UWB technology is essentially different from the existing wireless communication technology. The current wireless communication technology uses a continuous radio wave, which is like a person watering the lawn with a pipe, the water in the pipe fluctuates continuously with the movement of manpower. Almost all wireless communications, including mobile phones and wireless LAN communications, are like this: using a cer

802.11ac has made great strides in improving Wi-Fi performance by using a wider channel, a more efficient modulation mode (by transmitting data in RF waves), and multi-user connections (so-called multi-user MIMO. In fact, this kind of progress will come in a wave in the future. However, the new 2nd wave chip is different from the 1st wave device (please read the hardware upgrade) Remember that not all 802.11ac access points are the same. Many access p

Introduction and comparison of common audio protocols for conference TV white PaperFirst, the digital audio principle: The sound is actually a kind of energy wave, therefore also has the frequency and the amplitude characteristic, the frequency corresponds to the time axis, the amplitude corresponds to the level axis. Usually the ear can be heard in the frequency of 20Hz to 20KHz of sound waves known as audible, less than 20Hz to become infrasound, higher than 20KHz for ultrasound, multimedia te

seven layer model of the physical layer technology, the complexity of the first is that you must establish the transmission medium electrical characteristics, usually different transmission media for different frequency segments of the signal has different processing capacity. Ethernet wire processing baseband signal, WAN light out of high-frequency modulation signals, mobile communications, 2G and 3G respectively need to have different carrier frequ

to realize and other notable advantages, many electronic equipment, especially household appliances widely adopted, and more and more applications to computer systems.Second, features:The spectrum is outside the red light, the wavelength is 0.76~1.5μm, and the wavelength of the red light is longer, so the light is called infrared. Infrared remote control is the use of infrared to transmit information of a controlling system, infrared remote control (advantages) have anti-jamming, circuit simpl

includes: Auto identification systems, aids;application interface, api;middleware; application software. The automatic recognition system can be divided into data collection technology and feature collection technology according to the characteristics of recognition object. RFID Chinese is generally translated into radio frequency identification technology, non-contact identification technology. The typical RFID system consists of the tag electronic tag (transponder) Reader Reader (reading head

Android FM module learning-4 source code analysis (5) In the previous chapters, we analyzed several main class files of the FM module. What we want to analyze today is: FMTransceiver. java Public class FmTransceiver {/* Primary FM States: * FM will be in one of the 4 states at any point of time * '0'-FMState_Turned_Off * '1'-FMState_Rx_Turned_On * '2'-FMState_Tx_Turned_On * '3'-Timeout */ public static final int FMState_Turned_Off = 0; public static final int FMState_Rx_Turned_On = 1;

not both (and certainly not simultaneously). Two-way simultaneous communication (full-duplex communication)-both sides of the communication can send and receive information at the same time. Baseband signals (i.e. basic band signals)-signals from sources. Data signals such as computer output that represent a variety of text or image files belong to the baseband signal. Baseband signals often contain more low-frequency components, even DC components, and many channels do not transmit

: If your username and password input error, it is likely to cause 629 errors, we can re-enter the user name and password, enter the time to see if your key is open to enter the user name error, enter the completion of the user name, to see if there are more than a space. 2, the replacement line: Connecting the network line aging or crystal head failure may cause us to connect network failure, there are 629 errors, at this time we just replace the aging line or the fault of the crys

sharp weapon to solve the problem of communication network access ｡ 　　Wireless access technology type 6 DBS star access Technology DBS technology is also known as Digital live satellite access technology, which utilizes communications satellites located in geosynchronous orbit to send high speed broadcast data to the user's receiving antenna, so it is also known as high orbit satellite communications ｡ Its characteristic is the communication distance, the cost is independent from the distance

, ultra-five-class run Gigabit encoding method is relatively complex, equipment is relatively expensive. (Super Five class line running 1000Mbps, the flow of distribution to 8 copper wire, each copper also bear 125Mbps, but its frequency range only to 100MHz, which means 1Hz to produce 1.25bit, code modulation is more complex.) and six line with 1 to achieve 500Mbps, each line to assume 250Mbps, and its frequency range to 250mhz,1hz on the production

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