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With the rapid growth of the wireless mobile applications, wireless voice has
begun to challenge wireline voice, whereas the desire to access e-mail, surf the
Web or download music (e.g., MP3) wirelessly is increasing for wireless data.
While second generation (2G) cellular wireless systems, such as cdmaOne1,
GSM2 and TDMA3, introduced digital technology to wireless cellular systems
to deal with the increasing demand for wireless applications, there is still the
need for more spectrally efficient technologies for two reasons. First, wireless
voice capacity is expected to continue to grow. Second, the introduction of
high-speed wireless data will require more bandwidth.
標簽:
Wireless
Systems
Mobile
Beyond
and
3G
上傳時間:
2020-05-30
上傳用戶:shancjb
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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
-
Radio frequency spectrum is a scarce and critical natural resource that is utilized for
many services including surveillance, navigation, communication, and broadcast-
ing. Recent years have seen tremendous growth in the use of spectrum especially by
commercial cellular operators. Ubiquitous use of smartphones and tablets is one
of the reasons behind an all-time high utilization of spectrum. As a result, cellular
operators are experiencing a shortage of radio spectrum to meet bandwidth
demands of users. On the other hand, spectrum measurements have shown that
much spectrum not held by cellular operators is underutilized even in dense urban
areas. This has motivated shared access to spectrum by secondary systems with no
or minimal impact on incumbent systems. Spectrum sharing is a promising
approach to solve the problem of spectrum congestion as it allows cellular operators
access to more spectrum in order to satisfy the ever-growing bandwidth demands of
commercial users.
標簽:
Spectrum
Sharing
Between
Radars
上傳時間:
2020-06-01
上傳用戶:shancjb
-
Recent advances in wireless communication technologies have had a transforma-
tive impact on society and have directly contributed to several economic and social
aspects of daily life. Increasingly, the untethered exchange of information between
devices is becoming a prime requirement for further progress, which is placing an
ever greater demand on wireless bandwidth. The ultra wideband (UWB) system
marks a major milestone in this progress. Since 2002, when the FCC allowed the
unlicensed use of low-power, UWB radio signals in the 3.1–10.6GHz frequency
band, there has been significant synergistic advance in this technology at the cir-
cuits, architectural and communication systems levels. This technology allows for
devices to communicate wirelessly, while coexisting with other users by ensuring
that its power density is sufficiently low so that it is perceived as noise to other
users.
標簽:
Circuits
Wideband
Ultra
上傳時間:
2020-06-01
上傳用戶:shancjb
-
The use of optical free-space emissions to provide indoor wireless commu-
nications has been studied extensively since the pioneering work of Gfeller
and Bapst in 1979 [1]. These studies have been invariably interdisciplinary in-
volving such far flung areas such as optics design? indoor propagation studies?
electronics design? communications systems design among others. The focus
of this text is on the design of communications systems for indoor wireless
optical channels. Signalling techniques developed for wired fibre optic net-
works are seldom efficient since they do not consider the bandwidth restricted
nature of the wireless optical channel.
標簽:
Communication
Wireless
Optical
Systems
上傳時間:
2020-06-01
上傳用戶:shancjb
-
It has been said that the move from narrowband to broadband access is the second
revolution for the Internet — ‘broadband is more bandwidth than you can use’.
Once users have experienced broadband access there is no turning back. A whole
new world of applications and services becomes possible. No longer is it the ‘world-
wide wait’. The speed of response and visual quality enabled by broadband finally
allows the Internet to reach its true potential.
標簽:
Digital
Home
上傳時間:
2020-06-06
上傳用戶:shancjb
-
In the present era, low observability is one of the critical requirements in aerospace
sector, especially related to defense. The stealth technology essentially relates to
shaping and usage of radar absorbing materials (RAM) or radar absorbing struc-
tures (RAS). The performance of such radar cross section (RCS) reduction tech-
niques is limited by the bandwidth constraints, payload requirements, and other
structural issues. Moreover, with advancement of materials science, the structure
geometry no longer remains key decisive factor toward stealth.
標簽:
Fundamentals
Design
Radar
of
EM
上傳時間:
2020-06-06
上傳用戶:shancjb
-
Wherever possible the overall technique used for this series will be "definition by example" withgeneric formulae included for use in other applications. To make stability analysis easy we will usemore than one tool from our toolbox with data sheet information, tricks, rules-of-thumb, SPICESimulation, and real-world testing all accelerating our design of stable operational amplifier (op amp)circuits. These tools are specifically targeted at voltage feedback op amps with unity-gain bandwidths<20 MHz, although many of the techniques are applicable to any voltage feedback op amp. 20 MHz ischosen because as we increase to higher bandwidth circuits there are other major factors in closing theloop: such as parasitic capacitances on PCBs, parasitic inductances in capacitors, parasitic inductancesand capacitances in resistors, etc. Most of the rules-of-thumb and techniques were developed not justfrom theory but from the actual building of real-world circuits with op amps <20 MHz.
標簽:
運算放大器
上傳時間:
2021-11-01
上傳用戶:
-
Texas instruments MIPI DSI to eDP converter. Input supports 2 channel, 4 lanes each, up to 1.5GBit/s. Total input bandwidth is 12Gbit/s. Output eDP 1.4 1,2 or 4 lanes up to 5.4Gbit/s. output up to 4096x2304 60fps.
標簽:
mipi
dsi
上傳時間:
2021-12-22
上傳用戶:
-
Precision, Low Noise, CMOS, Rail-to-Rail,
Input/Output Operational Amplifiers
Data Sheet AD8605/AD8606/AD8608The AD8605, AD8606, and AD86081 are single, dual, and quad rail-to-rail input and output, single-supply amplifiers. They feature very low offset voltage, low input voltage and current noise, and wide signal bandwidth. They use the Analog Devices, Inc. patented DigiTrim? trimming technique, which achieves
標簽:
運算放大器
上傳時間:
2022-02-02
上傳用戶: