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Since the advent of optical communications, a great technological effort has
been devoted to the exploitation of the huge bandwidth of optical fibers. Start-
ing from a few Mb/s single channel systems, a fast and constant technological
development has led to the actual 10 Gb/s per channel dense wavelength di-
vision multiplexing (DWDM) systems, with dozens of channels on a single
fiber. Transmitters and receivers are now ready for 40 Gb/s, whereas hundreds
of channels can be simultaneously amplified by optical amplifiers.
標簽：
Communication
Techniques
Optical
Theory
and
上傳時間：
2020-05-31
上傳用戶：shancjb
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The idea for this book was born during one of my project-related trips to the beautiful city
of Hangzhou in China, where in the role of Chief Architect I had to guide a team of very
young, very smart and extremely dedicated software developers and verification engineers.
Soon it became clear that as eager as the team was to jump into the coding, it did not have
any experience in system architecture and design and if I did not want to spend all my time in
constant travel between San Francisco and Hangzhou, the only option was to groom a number
of local junior architects. Logically, one of the first questions being asked by these carefully
selected future architects was whether I could recommend a book or other learning material
that could speed up the learning cycle. I could not. Of course, there were many books on
various related topics, but many of them were too old and most of the updated information
was either somewhere on the Internet dispersed between many sites and online magazines, or
buried in my brain along with many years of experience of system architecture.
標簽：
Telecommunication
Gateways
System
Design
for
上傳時間：
2020-06-01
上傳用戶：shancjb
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Wireless communications has become a field of enormous scientific and economic interest. Recent
success stories include 2G and 3G cellular voice and data services (e.g., GSM and UMTS), wireless
local area networks (WiFi/IEEE 802.11x), wireless broadband access (WiMAX/IEEE 802.16x), and
digital broadcast systems (DVB, DAB, DRM). On the physical layer side, traditional designs typically
assume that the radio channel remains constant for the duration of a data block. However, researchers
and system designers are increasingly shifting their attention to channels that may vary within a block.
In addition to time dispersion caused by multipath propagation, these rapidly time-varying channels
feature frequency dispersion resulting from the Doppler effect. They are, thus, often referred to as
being “doubly dispersive.”
標簽：
Time-Varying
Channels
上傳時間：
2020-06-01
上傳用戶：shancjb
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Sound is simply an airborne version of vibration. The air which carries sound is a mixture
of gases. In gases, the molecules contain so much energy that they break free from
their neighbors and rush around at high speed. As Figure 1.1(a) shows, the innumerable
elastic collisions of these high-speed molecules produce pressure on the walls of any
gas container. If left undisturbed in a container at a constant temperature, eventually the
pressure throughout would be constant and uniform.
標簽：
Engineering
Audio
上傳時間：
2020-06-09
上傳用戶：shancjb
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This design uses Common-Emitter Amplifier (Class A) with 2N3904 Bipolar Junction Transistor.
Use “Voltage Divider Biasing” to reduce the effects of varying β (= ic / ib) (by holding the Base voltage constant)
Base Voltage (Vb) = Vcc * [R2 / (R1 + R2)]
Use Coupling Capacitors to separate the AC signals from the DC biasing voltage (which only pass AC signals and block any DC component).
Use Bypass Capacitor to maintain the Q-point stability.
To determine the value of each component, first set Q-point close to the center position of the load line. (RL is the resistance of the speaker.)
標簽：
音頻放大器設計
電路圖
英文
上傳時間：
2020-11-27
上傳用戶：
-
基于TMS320F2812 光伏并網發(fā)電模擬裝置PROTEL設計原理圖+PCB+軟件源碼+WORD論文文檔,硬件采用2層板設計，PROTEL99SE 設計的工程文件，包括完整的原理圖和PCB文件，可以做為你的學習設計參考。 摘要：本文實現了一個基于TMS320F2812 DSP芯片的光伏并網發(fā)電模擬裝置，采用直流穩(wěn)壓源和滑動變阻器來模擬光伏電池。通過TMS320F2812 DSP芯片ADC模塊實時采樣模擬電網電壓的正弦參考信號、光伏電池輸出電壓、負載電壓電流反饋信號等。經過數據處理后，用PWM模塊產生實時的SPWM 波，控制MOSFET逆變全橋輸出正弦波。本文用PI控制算法實現了輸出信號對給定模擬電網電壓的正弦參考信號的頻率和相位跟蹤，用恒定電壓法實現了光伏電池最大功率點跟蹤（MPPT），從而達到模擬并網的效果。另外本裝置還實現了光伏電池輸出欠壓、負載過流保護功能以及光伏電池輸出欠壓、過流保護自恢復功能、聲光報警功能、孤島效應的檢測、保護與自恢復功能。系統(tǒng)測試結果表明本設計完全滿定設計要求。關鍵詞：光伏并網，MPPT，DSP Photovoltaic Grid-connected generation simulator Zhangyuxin，Tantiancheng，Xiewuyang(College of Electrical Engineering, Chongqing University)Abstract: This paper presents a photovoltaic grid-connected generation simulator which is based on TMS320F2812 DSP, with a DC voltage source and a variable resistor to simulate the characteristic of photovoltaic cells. We use the internal AD converter to real-time sampling the referenced grid voltage signal, outputting voltage of photovoltaic, feedback outputting voltage and current signal. The PWM module generates SVPWM according to the calculation of the real-time sampling data, to control the full MOSFET inverter bridge output sine wave. We realized that the output voltage of the simulator can track the frequency and phase of the referenced grid voltage with PI regulation, and the maximum photovoltaic power tracking with constant voltage regulation, thereby achieved the purpose of grid-connected simulation. Additionally, this device has the over-voltage and over-current protection, audible and visual alarm, islanding detecting and protection, and it can recover automatically. The testing shows that our design is feasible.Keywords: Photovoltaic Grid-connected，MPPT，DSP 目錄引言 11. 方案論證 11.1. 總體介紹 11.2. 光伏電池模擬裝置 11.3. DC-AC逆變橋 11.4. MOSFET驅動電路方案 21.5. 逆變電路的變頻控制方案 22. 理論分析與計算 22.1. SPWM產生 22.1.1. 規(guī)則采樣法 22.1.2. SPWM 脈沖的計算公式 32.1.3. SPWM 脈沖計算公式中的參數計算 32.1.4. TMS320F2812 DSP控制器的事件管理單元 42.1.5. 軟件設計方法 62.2. MPPT的控制方法與參數計算 72.3. 同頻、同相的控制方法和參數計算 8
標簽：
tms320f2812
光伏
并網發(fā)電
模擬
protel
pcb
上傳時間：
2021-11-02
上傳用戶：
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The PW5410B is a low noise, constant frequency (1.2MHz) switched capacitor voltage doubler. Itproduces a regulated output voltage from 1.8V to 5V input with up to 100mA of output current. Lowexternal parts count (one flying capacitor and two small bypass capacitors at VIN and VOUT) makethe PW5410B ideally suited for small, battery-powered applications
標簽：
pw5410
上傳時間：
2022-02-11
上傳用戶：wangshoupeng199
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The PW5410A is a low noise, constant frequency (1.2MHz) switched capacitor voltage doubler. Itproduces a regulated output voltage from 2.7V to 5V input with up to 250mA of output current. Lowexternal parts count (one flying capacitor and two small bypass capacitors at VIN and VOUT) makethe PW5410A ideally suited for small, battery-powered applications
標簽：
pw5410
上傳時間：
2022-02-11
上傳用戶：
-
The PW4556 series of devices are highly integrated Li-Ion and Li-Pol linear chargers targetedat small capacity battery for portable applications. It is a complete constant-current/ constantvoltage linear charger. No external sense resistor is needed, and no blocking diode is required dueto the internal MOSFET architecture. It can deliver up to 300mA of charge current (using a goodthermal PCB layout) with a final float voltage accuracy of ±1%. The charge voltage is fixed at 4.2V or4.35V, and the charge current can be programmed externally with a single resistor. The chargerfunction has high accuracy current and voltage regulation loops and charge termination
標簽：
pw4556
上傳時間：
2022-02-11
上傳用戶：1208020161
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The PW4055 is a complete constant-current /constant-voltage linear charger for single cell lithiumion batteries.Its ThinSOT package and low external component count make the PW4055 ideallysuited for portable applications.Furthermore, the PW4055 is specifically designed to work within USBpower specifications.The PW4055 No external sense resistor is needed, and no blocking diode is required due to theinternal MOSFET architecture.Thermal feedback regulates the charge current to limit the dietemperature during high power operation or high ambient temperature. The charge voltage is fixedat 4.2V, and the charge current can be programmed externally with a single resistor. The PW4055automatically terminates the charge cycle when the charge current drops to 1/10th the programmedvalue after the final float voltage is reached. When the input supply (wall adapter or USB supply) isremoved, the PW4055 automatically enters a low current state, dropping the battery drain currentto less than 2μA. The PW4055 can be put into shutdown mode, reducing the supply current to 25μA.The BAT pin has a 7KV ESD(HBM) capability. Other features include charge current monitor, undervoltage lockout, automatic recharge and a status pin to indicate charge termination and the presenceof an input voltage
標簽：
pw4055
上傳時間：
2022-02-11
上傳用戶：jason_vip1
