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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.
標簽：
Next-Generation
Technologies
Wireless
上傳時間：
2020-05-31
上傳用戶：shancjb
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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.
標簽：
Measurements
Cellular
Phones
for
RF
上傳時間：
2020-06-01
上傳用戶：shancjb
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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.
標簽：
Telecommunications
Essentials
上傳時間：
2020-06-01
上傳用戶：shancjb
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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.
標簽：
Switch-Mode
Simulation
Supply
Power
上傳時間：
2020-06-07
上傳用戶：shancjb
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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.
標簽：
Feedback
Control
Theory
上傳時間：
2020-06-10
上傳用戶：shancjb
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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!
標簽：
開關電源
上傳時間：
2021-11-23
上傳用戶：
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本系統采用電動機電樞供電回路串接采樣電阻的方式來實現對小型直流有刷電動機的轉速測量。該系統主要由二階低通濾波電路,小信號放大電路、單片機測量顯示電路、開關穩壓電源電路等組成。同時自制電機測速裝置,用高頻磁環作為載體,用線圈繞制磁環,利用電磁感應原理檢測電機運行時的漏磁,將變化的磁場信號轉化為磁環上的感應電流。用信號處理單元電路將微弱電信號轉化為脈沖信號,送由單片機檢測,從而達到準確測量電機的速度的要求。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.
標簽：
直流電動機
上傳時間：
2022-03-26
上傳用戶：
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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.
標簽：
單片機
adpcm
編碼
解碼
上傳時間：
2022-06-20
上傳用戶：
