This book gives a comprehensive overview of the technologies for the advances of
mobile radio access networks. The topics covered include linear transmitters,
superconducting filters and cryogenic radio frequency (RF) front head, radio over
fiber, software radio base stations, mobile TERMINAL positioning, high speed
downlink packet access (HSDPA), multiple antenna systems such as smart
antennas and multiple input and multiple output (MIMO) systems, orthogonal
frequency division multiplexing (OFDM) systems, IP-based radio access networks
(RAN), autonomic networks, and ubiquitous networks.
By definition, the term “mobile-radio communications” describes any
radio communication link between two TERMINALs of which one or both
are in motion or halted at unspecified locations and of which one may
actually be a fixed TERMINAL such as a base station. This definition
applies to both mobile-to-mobile and mobile-to-fixed radio communica-
tion links. The mobile-to-mobile link could in fact consist of a mobile-
to-fixed-to-mobile radio communication link.The term “mobile” applies
to land vehicles, ships at sea, aircraft, and communications satellites.
In tactical situations, mobile-radio systems may include any or all of
these types of mobile TERMINALs.
The single-carrier frequency division multiple access (SC-FDMA)
system is a well-known system that has recently become a preferred
choice for mobile uplink channels. This is attributed to its advantages
such as the low peak-to-average power ratio (PAPR) and the use of
frequency domain equalizers. Low PAPR allows the system to relax
the specifications of linearity in the power amplifier of the mobile
TERMINAL, which reduces cost and power consumption.
設(shè)計(jì)了農(nóng)業(yè)溫濕度智能控制系統(tǒng),該系統(tǒng)采用DHT11溫濕度傳感器作為溫濕度采集模塊,單片機(jī)選用AT89C52代替并調(diào)用Virtual TERMINAL模擬串口通信,LCD1604液晶顯示器實(shí)時(shí)顯示溫濕度,實(shí)現(xiàn)了溫濕度的測(cè)量、顯示,可自動(dòng)控制加熱、降溫、加濕、通風(fēng),實(shí)現(xiàn)溫濕度控制以及超限報(bào)警處理,并利用Proteus與Keil進(jìn)行實(shí)際電路的仿真。試驗(yàn)表明,該系統(tǒng)實(shí)現(xiàn)了可靠的溫濕度監(jiān)控。We described the design of an intelligent control system of agriculture temperature and humidity.The system uses DHT11 temperature and humidity sensor as the temperature and humidity acquisition module.The SCM adopts AT89C52 to replace and call the virtual TERMINAL for simulating serial communication.LCD1604 displays temperature and humidity in real time,which implements the measurement and display of temperature and humidity.The system is able to automatically control heating,cooling,humidification and ventilation,to achieve temperature and humidity control and over-limit alarm processing.The system also uses Proteus and Keil for actual circuit simulation.The experiment shows that the system is capable of reliable temperature and humidity monitoring.
摘要：本系統(tǒng)以ICL8038集成塊為核心器件，制作一種函數(shù)信號(hào)發(fā)生器，制作成本較低。適合學(xué)生學(xué)習(xí)電子技術(shù)測(cè)量使用。ICL8038是一種具有多種波形輸出的精密振蕩集成電路，只需要個(gè)別的外部元件就能產(chǎn)生從0.001Hz~30KlHz的低失真正弦波、三角波、矩形波等脈沖信號(hào)。輸出波形的頻率和占空比還可以由電流或電阻控制。另外由于該芯片具有調(diào)制信號(hào)輸入端，所以可以用來對(duì)低頻信號(hào)進(jìn)行頻率調(diào)制。關(guān)鍵詞：函數(shù)信號(hào)發(fā)生器頻率調(diào)制Abstract：The system ICL8038 integrated block as the core device，producing a kind of function signal generator，producing low cost.Suitable for students to learn the use of electronic technology measurement.ICL8038 is a kind of multi-precision oscillator waveform output integrated circuits，a separate external components only need to be able to generate from the 0.001Hz ~30KHz low-distortion sine wave，triangle wave，square wave pulse signal，etc..Output waveform of the frequency and duty cycle can also be controlled by a currentor resistance.In addition，as the chip has a modulated signal input TERMINAL，it can be used to low-frequency signal is frequency modulation.
