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During the past decade, many wireless communication techniques have been
developedto achievevariousgoals suchas higherdata rate,morerobustlink quality,
and higher number of users in a given bandwidth. For wireless communication
systems, depending on the availability of a feedback link, two approaches can be
considered: namely open and closed loop. Open loop communication system that
does not exploit the channel knowledge at the transmitter is now well understood
from both a theoretical and practical point of view.
標(biāo)簽：
Communication
Strategies
Feedback
Wireless
for
上傳時(shí)間：
2020-05-27
上傳用戶：shancjb
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OSCILLATORS are key building blocks in integrated transceivers. In wired and
wireless communication terminals, the receiver front-end selects, amplifies and
converts the desired high-frequency signal to baseband. At baseband the signal can
then be converted into the digital domain for further data processing and demodula-
tion. The transmitter front-end converts an analog baseband signal to a suitable high-
frequency signal that can be transmitted over the wired or wireless channel.
標(biāo)簽：
High-Frequency
Oscillator
Design
上傳時(shí)間：
2020-05-27
上傳用戶：shancjb
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In order to improve the spectral efficiency in wireless communications, multiple
antennas are employed at both transmitter and receiver sides, where the resulting
system is referred to as the multiple-input multiple-output (MIMO) system. In
MIMO systems, it is usually requiredto detect signals jointly as multiple signals are
transmitted through multiple signal paths between the transmitter and the receiver.
This joint detection becomes the MIMO detection.
標(biāo)簽：
Complexity
Detection
MIMO
Low
上傳時(shí)間：
2020-05-27
上傳用戶：shancjb
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Many wireless communications channels consist of multiple signal paths from the
transmitter to receiver. This multiplicity of paths leads to a phenomenon known
as multipath fading. The multiple paths are caused by the presence of objects in the
physical environment that, through the mechanisms of propagation, alter the path of
radiated energy. These objects are referred to as scatterers. In the past, researchers
often looked at ways to mitigate multipath scattering, such as in diversity systems.
Multiple-input, multiple-output (MIMO) systems, on the other hand, use multipath
diversity to their advantage; a MIMO system has the ability to translate increased
spatial diversity into increased channel capacity.
標(biāo)簽：
Multiple-Output
Multiple-Input
Channel
Models
上傳時(shí)間：
2020-05-31
上傳用戶：shancjb
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By inventing the wireless transmitter or radio in 1897, the Italian physicist Tomaso
Guglielmo Marconi added a new dimension to the world of communications. This
enabled the transmission of the human voice through space without wires. For this
epoch-making invention, this illustrious scientist was honored with the Nobel Prize
for Physics in 1909. Even today, students of wireless or radio technology remember
this distinguished physicist with reverence. A new era began in Radio
Communications.
標(biāo)簽：
Radio
Frequency
Modulation
上傳時(shí)間：
2020-06-01
上傳用戶：shancjb
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A wireless communication network can be viewed as a collection of nodes, located in some domain, which
can in turn be transmitters or receivers (depending on the network considered, nodes may be mobile users,
base stations in a cellular network, access points of a WiFi mesh etc.). At a given time, several nodes
transmit simultaneously, each toward its own receiver. Each transmitter–receiver pair requires its own
wireless link. The signal received from the link transmitter may be jammed by the signals received from
the other transmitters. Even in the simplest model where the signal power radiated from a point decays in
an isotropic way with Euclidean distance, the geometry of the locations of the nodes plays a key role since
it determines the signal to interference and noise ratio (SINR) at each receiver and hence the possibility of
establishing simultaneously this collection of links at a given bit rate. The interference seen by a receiver is
the sum of the signal powers received from all transmitters, except its own transmitter.
標(biāo)簽：
Stochastic
Geometry
Networks
Wireless
Volume
and
II
上傳時(shí)間：
2020-06-01
上傳用戶：shancjb
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Wavelength division multiplexing (WDM) refers to a multiplexing and transmission
scheme in optical telecommunications fibers where different wavelengths, typically
emitted by several lasers, are modulated independently (i.e., they carry independent
information from the transmitters to the receivers). These wavelengths are then
multiplexed in the transmitter by means of passive WDM filters, and likewise they
are separated or demultiplexed in the receiver by means of the same filters or
coherent detection that usually involves a tunable local oscillator (laser).
標(biāo)簽：
Multiplexing
Wavelength
Division
上傳時(shí)間：
2020-06-01
上傳用戶：shancjb
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Universival Asychronous Receiver/transmitter（通用異步串行口），UART 是一種較為通用的數(shù)據(jù)傳輸?shù)姆椒ǎ碨tart Bit＋Data＋Check＋StopBit），而COM 口中Rx、Tx 的數(shù)據(jù)格式即為UART。UART 和RS232是兩種異步數(shù)據(jù)傳輸標(biāo)準(zhǔn).計(jì)算機(jī)中的COM1和COM2都是RS232串行通信標(biāo)準(zhǔn)接口。當(dāng)Uart 接口連到PC 機(jī)上時(shí)，需要接RS232電平轉(zhuǎn)換電路。
標(biāo)簽：
spi
uart
i2c
上傳時(shí)間：
2021-11-30
上傳用戶：
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近距電能傳輸——高效安全近距電能傳輸一般基于電磁感應(yīng)原理進(jìn)行。在此技術(shù)基礎(chǔ)上，當(dāng)接收器鄰近發(fā)射器時(shí)才會進(jìn)行電能傳輸。電磁感應(yīng)技術(shù)的歷史長達(dá)百年，多年米一直應(yīng)用于各類電子產(chǎn)品中—如此普及全因其簡單、高效以及安全技術(shù)概覽以下將為你簡要介紹無線電能傳輸技術(shù)。System Overview(Communication)Receiver sends messagesTo provide control information to the transmitterBy load modulation on the power signatransmitter receives messagesTo receive control information frorn the recelverBy de-modulation of the reflected loadPower Pick Up( Receiver)Secondary coil (L Serial resonance capacitor (C) for efficient power transfer Parallel resonance capacitor(C, )for detection purposes Rectifier: full bridge(diode, or switched)+ capacitor Output switch for(dis)connecting the loadReceiver modulates load by Switching modulation resistor(R,n),or Switching modulation capacitor(Ca)transmitter de-modulates reflected load by Sensing pnmary coil curent (p)and/o Sensing primary coil voltage (V,
標(biāo)簽：
qi
無線充電
上傳時(shí)間：
2022-03-31
上傳用戶：
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基于TMS320F28335的超聲波流量計(jì)硬件原理圖+軟件源碼本文以TMS320F28335 處理器為核心，設(shè)計(jì)一種用于管道流量測量的超聲波流量計(jì)。系統(tǒng)硬件由核心板，超聲波發(fā)射和接收電路，切換電路，超聲換能器，基于ADS805 的高速信號采集電路，人機(jī)交互以及電源等模塊構(gòu)成。采用時(shí)差法進(jìn)行管道流量測量，時(shí)差測量采用SCOT 加權(quán)的廣義互相關(guān)時(shí)延估計(jì)算法。本論文設(shè)計(jì)的超聲波流量計(jì)具有測量速度快、準(zhǔn)確性好、成本低等優(yōu)點(diǎn)。關(guān)鍵字：C2000，超聲波，流量，廣義互相關(guān)算法AbstractA kind of ultrasonic flowmeter using for the pipe flow measurement is designed based onTMS320F28335 in this paper. The system hardware consists of the following parts: the core board,ultrasonic signal transmitter and receiver circuits, switch circuit, ultrasonic transducer, signalacquisition circuit based on ADS805, human-computer interaction module and power supplymodule, etc. The system use the method of time difference for pipeline flow measurement and thetime difference is calculated by the time-delay algorithm of SCOT weighted generalizedcross-correlation. The ultrasonic flowmeter has the features of high testing speed, high precisionand low cost, etc.Keywords: C2000,Ultrasonic, Flow, Generalized Cross-Correlation Algorithm
標(biāo)簽：
tms320f28335
超聲波流量計(jì)
上傳時(shí)間：
2022-05-06
上傳用戶：
