In the past few decades, a technological revolution has occurred that has Changed the way we live in dramatic ways. This technological revolution is the result of the emergence and evolution of a wide variety of new wireless networking tech- nologies. Now people using these technologies are able to access the network and control many applications at will with their handheld devices anywhere, anytime. Although these technologies have made a long lasting impact in the revolution, it has also opened up various challenging issues which are yet to be resolved to make them more efficient and cost-effective.
標(biāo)簽： Next-Generation Technologies Wireless
上傳時(shí)間： 2020-05-31
上傳用戶：shancjb
The market for cellular phones and wireless data transmission equipment has Changed dramatically since the late 1970s when cellular phones were first introduced and the late 1980s when wireless data equipment became available. As would be expected, duringthistime RF test requirements and RF test equipment has Changed dramatically.
標(biāo)簽： Measurements Cellular Phones for RF
上傳時(shí)間： 2020-06-01
上傳用戶：shancjb
I love telecommunications. It is powerful and it empowers, with far-reaching consequences. It has demonstrated the potential to transform society and business, and the revolution has only just begun. With the invention of the telephone, human communications and commerce were forever Changed: Time and distance began to melt away as a barrier to doing business, keeping in touch with loved ones, and being able to immediately respond to major world events. Through the use of computers and telecommunications networks, humans have been able to extend their powers of thinking, influence, and productivity, just as those in the Industrial Age were able to extend the power of their muscles, or physical self, through use of heavy machinery.
標(biāo)簽： Telecommunications Essentials
上傳時(shí)間： 2020-06-01
上傳用戶：shancjb
Thepredecessorvolumeofthisbookwaspublishedin1996.Intheyears since then, some things have Changed and some have not. Two of the things that have not Changed are the desire for better models and faster simulations. I performed the original simulations on my “hyperfast” 133-MHz computer! At the time, I thought if I could just getafastercomputer,allofourSPICEproblemswouldbehistory,right? TodayIamsimulatingonacomputerthathasa2.6-GHzprocessorwith 512 MB of RAM, and I would still say that simulations run too slow. The computer technology has evolved, but so have the models. In 1996 wewereperformingsimulationson100-kHzpowerconverters,whereas today I routinely see 1- and 2-MHz power converters.
標(biāo)簽： Switch-Mode Simulation Supply Power
上傳時(shí)間： 2020-06-07
上傳用戶：shancjb
Striking developments have taken place since 1980 in feedback control theory. The subject has be- come both more rigorous and more applicable. The rigor is not for its own sake, but rather that even in an engineering discipline rigor can lead to clarity and to methodical solutions to problems. The applicability is a consequence both of new problem formulations and new mathematical solutions to these problems. Moreover, computers and software have Changed the way engineering design is done. These developments suggest a fresh presentation of the subject, one that exploits these new developments while emphasizing their connection with classical control.
標(biāo)簽： Feedback Control Theory
上傳時(shí)間： 2020-06-10
上傳用戶：shancjb
It all started rather innocuously. I walked into Dr GT Murthy’s office one fine day, andChanged my life. “Doc” was then the General Manager, Central R&D, of a very largeelectrical company headquartered in Bombay. In his new state-of-the-art electronics center,he had hand-picked some of India’s best engineers (over a hundred already) ever assembledunder one roof. Luckily, he too was originally a Physicist, and that certainly helped me gainsome empathy. Nowadays he is in retirement, but I will always remember him as athoroughly fair, honest and facts-oriented person, who led by example. There were severalthings I absorbed from him that are very much part of my basic engineering persona today.You can certainly look upon this book as an extension of what Doc started many years agoin India … because that’s what it really is! I certainly wouldn’t be here today if I hadn’t metDoc. And in fact, several of the brash, high-flying managers I’ve met in recent years,desperately need some sort of crash course in technology and human values from Doc!
標(biāo)簽： 開(kāi)關(guān)電源
上傳時(shí)間： 2021-11-23
上傳用戶：
本系統(tǒng)采用電動(dòng)機(jī)電樞供電回路串接采樣電阻的方式來(lái)實(shí)現(xiàn)對(duì)小型直流有刷電動(dòng)機(jī)的轉(zhuǎn)速測(cè)量。該系統(tǒng)主要由二階低通濾波電路,小信號(hào)放大電路、單片機(jī)測(cè)量顯示電路、開(kāi)關(guān)穩(wěn)壓電源電路等組成。同時(shí)自制電機(jī)測(cè)速裝置,用高頻磁環(huán)作為載體,用線圈繞制磁環(huán),利用電磁感應(yīng)原理檢測(cè)電機(jī)運(yùn)行時(shí)的漏磁,將變化的磁場(chǎng)信號(hào)轉(zhuǎn)化為磁環(huán)上的感應(yīng)電流。用信號(hào)處理單元電路將微弱電信號(hào)轉(zhuǎn)化為脈沖信號(hào),送由單片機(jī)檢測(cè),從而達(dá)到準(zhǔn)確測(cè)量電機(jī)的速度的要求。In this system, the sampling resistance of armature power supply circuit is connected in series to measure the speed of small DC brush motor. The system is mainly composed of second-order low-pass filter circuit, small signal amplifier circuit, single-chip measurement and display circuit, switching regulated power supply circuit and so on. At the same time, the self-made motor speed measuring device uses high frequency magnetic ring as the carrier, coil winding magnetic ring, and electromagnetic induction principle to detect the leakage of magnetic field during the operation of the motor, which converts the Changed magnetic field signal into the induced current on the magnetic ring. The weak electric signal is transformed into pulse signal by signal processing unit circuit, which is sent to single chip computer for detection, so as to meet the requirement of accurate measurement of motor speed.
標(biāo)簽： 直流電動(dòng)機(jī)
上傳時(shí)間： 2022-03-26
上傳用戶：
INTRODUCTION In the past, adding speech recording and playback capability to a product meant using a digital signal processor or a specialized audio chip. Now, using a simplified Adaptive Differential Pulse Code Modulation(ADPCM) algorithm, these audio capabilities can be added to any PICmicro device. This application note will cover the ADPCM compression and decompression algorithms, performance comparison of all PICmicro devices, and an application using a PIC16C72 micro-controller.DEFINITION OF TERMS step size -value of the step used for quantization of ana-log signals and inverse quantization of a number of steps.quantization -the digital form of an analog input signal is represented by a finite number of steps.adaptive quantization -the step size of a quantizer is dramatically Changed with time in order to adapt to a changing input signal.inverse quantizer -a finite number of steps is converted into a digital representation of an analog signal.
上傳時(shí)間： 2022-06-20
上傳用戶：
蟲(chóng)蟲(chóng)下載站版權(quán)所有 京ICP備2021023401號(hào)-1
