This is a book on wireless communication. That usually means communica- tion by radio, though ultrasound and infrared light are also used occasion- ally. The term “wireless” has come to mean nonbroadcast communication, usually between individuals who very often use portable or mobile equip- ment. The term is rather vague, of course, and there are certainly borderline applications that are called wireless without falling exactly into the above definition.
標(biāo)簽： Communication Technology Wireless
上傳時(shí)間： 2020-06-01
上傳用戶(hù)：shancjb
Artificial Intelligence (AI) has undoubtedly been one of the most important buz- zwords over the past years. The goal in AI is to design algorithms that transform com- puters into “intelligent” agents. By intelligence here we do not necessarily mean an extraordinary level of smartness shown by superhuman; it rather often involves very basic problems that humans solve very frequently in their day-to-day life. This can be as simple as recognizing faces in an image, driving a car, playing a board game, or reading (and understanding) an article in a newspaper. The intelligent behaviour ex- hibited by humans when “reading” is one of the main goals for a subfield of AI called Natural Language Processing (NLP). Natural language 1 is one of the most complex tools used by humans for a wide range of reasons, for instance to communicate with others, to express thoughts, feelings and ideas, to ask questions, or to give instruc- tions. Therefore, it is crucial for computers to possess the ability to use the same tool in order to effectively interact with humans.
標(biāo)簽： Embeddings Processing Language Natural in
上傳時(shí)間： 2020-06-10
上傳用戶(hù)：shancjb
Machine learning is about designing algorithms that automatically extract valuable information from data. The emphasis here is on “automatic”, i.e., machine learning is concerned about general-purpose methodologies that can be applied to many datasets, while producing something that is mean- ingful. There are three concepts that are at the core of machine learning: data, a model, and learning.
上傳時(shí)間： 2020-06-10
上傳用戶(hù)：shancjb
mosfet并聯(lián)使用介紹了并聯(lián)使用的注意事項(xiàng)，特別注意避開(kāi)Vgsth zero thermal coefficient以下的正溫特性設(shè)計(jì)
上傳時(shí)間： 2022-03-01
上傳用戶(hù)：bluedrops
華為AI安全白皮書(shū)2018-cn近年來(lái)，隨著海量數(shù)據(jù)的積累、計(jì)算能力的發(fā)展、機(jī)器學(xué)習(xí)方法與系統(tǒng)的持續(xù)創(chuàng)新與演進(jìn)，諸如圖像識(shí)別、語(yǔ)音識(shí) 別、自然語(yǔ)言翻譯等人工智能技術(shù)得到普遍部署和廣泛應(yīng)用。越來(lái)越多公司都將增大在AI的投入，將其作為業(yè)務(wù)發(fā)展 的重心。華為全球產(chǎn)業(yè)愿景預(yù)測(cè)：到2025年，全球?qū)?shí)現(xiàn)1000億聯(lián)接，覆蓋77%的人口；85%的企業(yè)應(yīng)用將部署到 云上；智能家庭機(jī)器人將進(jìn)入12%的家庭，形成千億美元的市場(chǎng)。 人工智能技術(shù)的發(fā)展和廣泛的商業(yè)應(yīng)用充分預(yù)示著一個(gè)萬(wàn)物智能的社會(huì)正在快速到來(lái)。1956年，麥卡錫、明斯基、 香農(nóng)等人提出“人工智能”概念。60年后的今天，伴隨著谷歌DeepMind開(kāi)發(fā)的圍棋程序AlphaGo戰(zhàn)勝人類(lèi)圍棋冠 軍，人工智能技術(shù)開(kāi)始全面爆發(fā)。如今，芯片和傳感器的發(fā)展使“+智能”成為大勢(shì)所趨：交通+智能，最懂你的 路；醫(yī)療+智能，最懂你的痛；制造+智能，最懂你所需。加州大學(xué)伯克利分校的學(xué)者們認(rèn)為人工智能在過(guò)去二十年 快速崛起主要?dú)w結(jié)于如下三點(diǎn)原因[1]：1）海量數(shù)據(jù)：隨著互聯(lián)網(wǎng)的興起，數(shù)據(jù)以語(yǔ)音、視頻和文字等形式快速增 長(zhǎng)；海量數(shù)據(jù)為機(jī)器學(xué)習(xí)算法提供了充足的營(yíng)養(yǎng)，促使人工智能技術(shù)快速發(fā)展。2）高擴(kuò)展計(jì)算機(jī)和軟件系統(tǒng)：近 年來(lái)深度學(xué)習(xí)成功主要?dú)w功于新一波的CPU集群、GPU和TPU等專(zhuān)用硬件和相關(guān)的軟件平臺(tái)。3）已有資源的可獲得 性：大量的開(kāi)源軟件協(xié)助處理數(shù)據(jù)和支持AI相關(guān)工作，節(jié)省了大量的開(kāi)發(fā)時(shí)間和費(fèi)用；同時(shí)許多云服務(wù)為開(kāi)發(fā)者提供 了隨時(shí)可獲取的計(jì)算和存儲(chǔ)資源。 在機(jī)器人、虛擬助手、自動(dòng)駕駛、智能交通、智能制造、智慧城市等各個(gè)行業(yè)，人工智能正朝著歷史性時(shí)刻邁進(jìn)。谷 歌、微軟、亞馬遜等大公司紛紛將AI作為引領(lǐng)未來(lái)的核心發(fā)展戰(zhàn)略。2017年谷歌DeepMind升級(jí)版的AlphaGo Zero橫 空出世；它不再需要人類(lèi)棋譜數(shù)據(jù)，而是進(jìn)行自我博弈，經(jīng)過(guò)短短3天的自我訓(xùn)練就強(qiáng)勢(shì)打敗了AlphaGo。AlphaGo Zero能夠發(fā)現(xiàn)新知識(shí)并發(fā)展出打破常規(guī)的新策略，讓我們看到了利用人工智能技術(shù)改變?nèi)祟?lèi)命運(yùn)的巨大潛能。 我們現(xiàn)在看到的只是一個(gè)開(kāi)始；未來(lái)，將會(huì)是一個(gè)全聯(lián)接、超智能的世界。人工智能將為人們帶來(lái)極致的體驗(yàn)，將 積極影響人們的工作和生活，帶來(lái)經(jīng)濟(jì)的繁榮與發(fā)展。
上傳時(shí)間： 2022-03-06
上傳用戶(hù)：
隨著光伏發(fā)電系統(tǒng)快速發(fā)展,以及電動(dòng)汽車(chē)充電樁的普及,傳統(tǒng)的剩余電流保護(hù)器無(wú)法滿足實(shí)際需求。介紹了一款B型剩余電流保護(hù)器,采用磁調(diào)制剩余電流互感器和零序電流互感器采集剩余電流。根據(jù)GB/T 22794—2017標(biāo)準(zhǔn)要求,可識(shí)別1 kHz及以下的正弦交流、帶和不帶直流分量的脈動(dòng)直流、平滑直流等剩余電流信號(hào)。經(jīng)信號(hào)調(diào)理電路將電壓信號(hào)送到單片機(jī)進(jìn)行采集和判斷。通過(guò)試驗(yàn)測(cè)試,該樣機(jī)在測(cè)試精度和速度上均符合國(guó)家標(biāo)準(zhǔn)的相關(guān)要求。The rapid development of photovoltaic power generation systems and the popularity of electric vehicle charging piles make the traditional residual current protective devices unable to meet the actual demand.This paper proposed a type B residual current protective device,which uses the magnetically modulated residual current transformer and the zero sequence current transformer to acquire the residual current.According to the requirements of GB/T 22794—2017,the type B residual current protective device can detect sinusoidal AC residual current of 1kHz and below 1kHz,pulsating DC residual current with and without DC component,smooth DC residual current and so on.The signal processing circuit sends the voltage signal to the MCU for acquisition and judgment.Through experimental tests,the device meets the relevant requirements of national standards in terms of test accuracy and speed.
標(biāo)簽： 電流保護(hù)器
上傳時(shí)間： 2022-03-27
上傳用戶(hù)：
針對(duì)交流電路過(guò)零檢測(cè)電路存在結(jié)構(gòu)復(fù)雜、過(guò)零點(diǎn)檢測(cè)不準(zhǔn)確、編程繁瑣等問(wèn)題，設(shè)計(jì)了一種基于LM339的硬件結(jié)構(gòu)簡(jiǎn)單的過(guò)零檢測(cè)電路。通過(guò)仿真軟件Mulisim對(duì)該設(shè)計(jì)電路進(jìn)行了仿真，實(shí)驗(yàn)證明了該方案過(guò)零檢測(cè)的可行性、穩(wěn)定性和可靠性，可直接作為交流電路中CPU的過(guò)零信號(hào)。Aiming at the problems of AC cilsuit zero crossing detection circuit such as complex structure, zero crossing detection and cumbersome programming, a zero crossing detection circuit with simple hardware structure based on LM339 was designed. The design circuit was simulated by simulation software Mulisim, and the feasibility, stability and reliability of zero crossing detection were proved by experiments, which can be used as zero crossing signal of CPU in AC circuit directly.
上傳時(shí)間： 2022-05-03
上傳用戶(hù)：
The JW? 7805 is a low noise low-dropout (LDO) voltage regulator with enable function that operates from 1.8V to 5.5V. It provides up to 300mA of output current and offers low-power operation in miniaturized packaging. JW7805 supports fixed output voltage 0.9V, 1.0V, 1.05V, 1.1V,1.2V, 1.3V, 1.35V, 1.5V, 1.8V, 1.85V, 2.1V, 2.2V, 2.3V, 2.5V, 2.6V, 2.7V, 2.8V, 2.85V, 2.9V, 3.0V,3.1V, 3.3V, 3.6V, 4.2V, 4.4V and 5.0V. The features of low quiescent current as low as 6uA and almost zero disable current are ideal for powering the battery equipment. JW7805’s low output noise and high PSRR are also friendly to RF systems.
標(biāo)簽： JW7805
上傳時(shí)間： 2022-05-06
上傳用戶(hù)：slq1234567890
本文以感應(yīng)加熱電源為研究對(duì)象，闡述了感應(yīng)加熱電源的基本原理及其發(fā)展趨勢(shì)。對(duì)感應(yīng)加熱電源常用的兩種拓?fù)浣Y(jié)構(gòu)-電流型逆變器和電壓型逆變器做了比較分析，并分析了感應(yīng)加熱電源的各種調(diào)功方式。在對(duì)比幾種功率調(diào)節(jié)方式的基礎(chǔ)上，得出在整流側(cè)調(diào)功有利于高頻感應(yīng)加熱電源頻率和功率的提高的結(jié)論，選擇了不控整流加軟斬波器調(diào)功的感應(yīng)加熱電源作為研究對(duì)象，針對(duì)傳統(tǒng)硬斬波調(diào)功式感應(yīng)加熱電源功率損耗大的缺點(diǎn)，采用軟斬波調(diào)功方式，設(shè)計(jì)了一種零電流開(kāi)關(guān)準(zhǔn)諾振變換器ZCS-QRCs（Zero-current-switching-Quasi-resonant）倍頻式串聯(lián) 振高頻感應(yīng)加熱電源。介紹了該軟斬波調(diào)功器的組成結(jié)構(gòu)及其工作原理，通過(guò)仿真和實(shí)驗(yàn)的方法研究了該軟斬波器的性能，從而得出該軟斬波器非常適合大功率高頻感應(yīng)加熱電源應(yīng)用場(chǎng)合的結(jié)論。同時(shí)設(shè)計(jì)了功率閉環(huán)控制系統(tǒng)和PI功率調(diào)節(jié)器，將感應(yīng)加熱電源的功率控制問(wèn)題轉(zhuǎn)化為Buck斬波器的電壓控制問(wèn)題。針對(duì)目前IGBT器件頻率較低的實(shí)際情況，本文提出了一種新的逆變拓?fù)?通過(guò)IGBT的并聯(lián)來(lái)實(shí)現(xiàn)倍頻，從而在保證感應(yīng)加熱電源大功率的前提下提高了其工作頻率，并在分析其工作原理的基礎(chǔ)上進(jìn)行了仿真，驗(yàn)證了理論分析的正確性，達(dá)到了預(yù)期的效果。另外，本文還設(shè)計(jì)了數(shù)字鎖相環(huán)（DPLL），使逆變器始終保持在功率因數(shù)近似為1的狀態(tài)下工作，實(shí)現(xiàn)電源的高效運(yùn)行。最后，分析并設(shè)計(jì)了1GBT的緩沖吸收電路。本文第五章設(shè)計(jì)了一臺(tái)150kHz，10KW的倍頻式感應(yīng)加熱電源實(shí)驗(yàn)樣機(jī)，其中斬波器頻率為20kHz，逆變器工作頻率為150kHz（每個(gè)IGBT工作頻率為75kHz），控制孩心采用TI公司的TMS320F2812 DSP控制芯片，簡(jiǎn)化了系統(tǒng)結(jié)構(gòu)。實(shí)驗(yàn)結(jié)果表明，該倍頻式感應(yīng)加熱電源實(shí)現(xiàn)了斬波器和逆變器功率器件的軟開(kāi)關(guān)，有效的減小了開(kāi)關(guān)損耗，并實(shí)現(xiàn)了數(shù)字化，提高了整機(jī)效率。文章給出了整機(jī)的結(jié)構(gòu)設(shè)計(jì)，直流斬波部分控制框圖，逆變控制框圖，驅(qū)動(dòng)電路的設(shè)計(jì)和保護(hù)電路的設(shè)計(jì)。同時(shí)，給出了關(guān)鍵電路的仿真和實(shí)驗(yàn)波形。
上傳時(shí)間： 2022-06-22
上傳用戶(hù)：
The GD32F103xx device is a 32-bit general-purpose microcontroller based on the ARM?Cortex?-M3 RISC core with best ratio in terms of processing power, reduced power consumption and peripheral set. The Cortex?-M3 is a next generation processor core whichis tightly coupled with a Nested Vectored Interrupt Controller (NVIC), SysTick timer and advanced debug support.The GD32F103xx device incorporates the ARM ' Cortex?-M3 32-bit processor core operating at 108 MHz frequency with Flash accesses zero wait states to obtain maximumefficiency. It provides up to 3 MB on-chip Flash memory and up to 96 KB SRAM memory. An extensive range of enhanced I/Os and peripherals connected to two APB buses. The devices offer up to three 12-bit ADCs, up to two 12-bit DACs, up to ten general-purpose
標(biāo)簽： gd32f103
上傳時(shí)間： 2022-07-23
上傳用戶(hù)：aben
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