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Radio frequency (RF) power amplifiers are used in everyday life for many applica-
tions including cellular phones, magnetic resonance imaging, semiconductor wafer
processing for chip manufacturing, etc. Therefore, the design and performance of
RF amplifiers carry great importance for the proper functionality of these devices.
Furthermore, several industrial and military applications require low-profile yet
high-powered and efficient power amplifiers.
標簽：
Introduction
Amplifier
Design
Power
to
RF
上傳時間：
2020-05-27
上傳用戶：shancjb
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With the rapid expansion of wireless consumer products,there has been a con-
siderable increase in the need for radio-frequency (RF) planning, link plan-
ning, and propagation modeling.A network designer with no RF background
may find himself/herself designing a wireless network. A wide array of RF
planning software packages can provide some support, but there is no substi-
tute for a fundamental understanding of the propagation process and the lim-
itations of the models employed. Blind use of computer-aided design (CAD)
programs with no understanding of the physical fundamentals underlying the
process can be a recipe for disaster. Having witnessed the results of this
approach, I hope to spare others this frustration.
標簽：
Introduction
Propagation
to
RF
上傳時間：
2020-05-27
上傳用戶：shancjb
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Nature is seldom kind. One of the most appealing uses for radio-
telephone systems—communication with people on the move—must over-
come radio transmission problems so difficult they challenge the imagina-
tion. A microwave radio signal transmitted between a fixed base station
and a moving vehicle in a typical urban environment exhibits extreme
variations in both amplitude and apparent frequency.
標簽：
Communications
Microwave
Mobile
上傳時間：
2020-05-28
上傳用戶：shancjb
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Multi-carrier modulation? Orthogonal Frequency Division Multi-
plexing (OFDM) particularly? has been successfully applied to
a wide variety of digital communications applications over the past
several years. Although OFDM has been chosen as the physical layer
standard for a diversity of important systems? the theory? algorithms?
and implementation techniques remain subjects of current interest.
This is clear from the high volume of papers appearing in technical
journals and conferences.
標簽：
COMMUNICATIONS
MULTI-CARRIER
DIGITAL
上傳時間：
2020-05-31
上傳用戶：shancjb
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his research aims at creating broadband tunable, fully integrated filters for the application of
cognitive radio and signal classification receivers. The approach under study is the N-path filter
technique which is capable of translating a baseband impedance to a reference frequency creating
a tunable filter. The traditional N-path filter suffers from fundamental architectural limitations,
namely : a trade-off between insertion loss and out-of-band rejection, reference clock feed-
through, and jammer power handling limitations. In the first approach, the fundamental trade-
off of the traditional N-path filter between insertion loss and out-of-band rejection is improved by
a transmission line (T-line) N-path filter technique.
標簽：
Filtering
N-path
上傳時間：
2020-05-31
上傳用戶：shancjb
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All wireless communication standards, existing and under development, adopt or
consider adopting orthogonal Frequency-division multiplexing (OFDM) as the
modulation technique. It is clear that OFDM has become the definitive modulation
scheme in current and future wireless communication systems.
標簽：
Baseband
Receiver
Design
OFDM
上傳時間：
2020-05-31
上傳用戶：shancjb
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Before delving into the details of orthogonal frequency division multiplexing (OFDM), relevant
background material must be presented first. The purpose of this chapter is to provide the necessary
building blocks for the development of OFDM principles. Included in this chapter are reviews of stochastic
and random process, discrete-time signals and systems, and the Discrete Fourier Transform (DFT). Tooled
with the necessary mathematical foundation, we proceed with an overview of digital communication
systems and OFDM communication systems. We conclude the chapter with summaries of the OFDM
wireless LAN standards currently in existence and a high-level comparison of single carrier systems versus
OFDM.
標簽：
Wireless
OFDM
LANS
上傳時間：
2020-05-31
上傳用戶：shancjb
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Emerging technologies such as WiFi and WiMAX are profoundly changing the
landscape of wireless broadband. As we evolve into future generation wireless
networks, a primary challenge is the support of high data rate, integrated multi-
media type traffic over a unified platform. Due to its inherent advantages in
high-speed communication, orthogonal frequency division multiplexing (OFDM)
has become the modem of choice for a number of high profile wireless systems
(e.g., DVB-T, WiFi, WiMAX, Ultra-wideband).
標簽：
OFDM-Based
Broadband
Networks
Wireless
上傳時間：
2020-05-31
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Radio propagation measurements and channel modelling continue to be of fundamental importance
to radio system design. As new technology enables dynamic spectrum access and higher data rates,
radio propagation effects such as shadowing, the presence of multipath and frequency dispersion
are the limiting factors in the design of wireless communication systems. While there are several
books covering the topic of radio propagation in various frequency bands, there appears to be no
books on radio propagation measurements, which this book addresses at length.
標簽：
Propagation
Measurement
Radio
上傳時間：
2020-06-01
上傳用戶：shancjb
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One of the prerequisites for the development of telecommunication services is the
understanding of the propagation of the waves, either acoustic, electromagnetic,
radio or light waves, which are used for the transmission of information.
In this work, we shall limit ourselves to the study of radio waves: this term
apply to the electromagnetic waves used in radio communications. Their
frequency spectrum is very broad, and is divided into the following frequency
bands : ELF waves (f < 3 kHz), VLF (3-30 kHz), LF waves (30-300 kHz), MF
waves (300-3000 kHz), HF (3-30 MHz), VHF waves (30-300 MHz), UHF waves
(300-3000 MHz), SHF waves (3-30 GHz), EHF waves (30-300 GHz) and sub-
EHF waves (300-3000 GHz).
標簽：
Propagation
Radio
Wave
上傳時間：
2020-06-01
上傳用戶：shancjb
