This book was born from the perception that there is much more to spectrum use
and sharing than one sees reflected in publications, whether academic, commercial
or political. the former – in good research style – tend towards reductionism and
concentrate on specific, detailed aspects. commercial publications tend to empha-
size the positive aspects and they tend to put promise above practice. Given the ever
increasing pace of technology development and recent successes of new wireless
technologies, some pundits predict large-scale spectrum scarcity, potentially lead-
ing to economic catastrophe. Although economic theory has a hard time explaining
recent events that shook the world economy, the notion of spectrum scarcity is intui-
tively acceptable, even if not correct or immediately relevant.
The radio spectrum is one of the most precious resources which must be managed
to ensure efficient access for the wireless communication services which use it. The
allocation and management of spectrum are administered by the regulatory
authorities. Traditionally, spectrum allocation is carried out exclusively of its use in
large geographic areas and assigning frequency bands to specific users or service
providers is proved to be inefficient. Recently, substantial knowledge about
dynamic spectrum access scheme has been accumulated to enable efficient spectrum
sharing.
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.
A light-emitting diode (LED) is a semiconductor device that emits narrow-spectrum incoherent light when forward-biased.The color of the emitted light depends on the chemical composition of the semiconductor material used, and can benear-ultraviolet, visible or infrared. LEDs are more prevalent today than ever before, replacing traditional incandescent andfluorescent bulbs in many lighting applications. Incandescents use a heated filament, are subject to breakage and burnoutand operate at a luminous efficiency of 2% to 4%. Fluorescents are more efficient, at 7% to 12%, but require highdrive voltage and contain mercury, a toxic substance that may be eventually banned in certain countries. LEDs, however,produce light directly through electroluminescence, operate at low voltage and can deliver over 20% luminous efficiency.
為了使音頻信號分析儀小巧可靠，成本低廉，設計了以2片MSP430F1611單片機為核心的系統(tǒng)。該系統(tǒng)將音頻信號送入八階巴特沃茲低通濾波器，對信號進行限幅放大、衰減、電平位移、緩沖，并利用一單片機負責對前級處理后的模擬信號進行采樣，將采集得到的音頻信號進行4 096點基2的FFT計算，并對信號加窗函數(shù)提高分辨率，另一單片機負責對信號的分析及控制顯示設備。此設計精確的測量了音頻信號的功率譜、周期性、失真度指標，達到較高的頻率分辨率，并能將測量結(jié)果通過紅外遙控器顯示在液晶屏上。
Abstract:
o make the audio signal analyzer cheaper， smaller and more reliable， this system sends the audio signal to the eight-order butterworth filter， and then amplifies， attenuates， buffers it in a limiting range， transfers the voltage level of the signal before utilizing two MSP430F1611 MCU to realize the audio analysis. One is charged for sampling and dealing with the processed audio signal collected by the 4096 point radix-2 FFT calculation and imposes the window function to improve the frequency resolution. The other one controls the display and realizes the spectrum， periodicity， power distortion analysis in high resolution which is displayed in the LCD screen through the infrared remote control.
This application report discusses the design of non-invasive optical plethysmographyalso called as pulsoximeter using the MSP430FG437 Microcontroller (MCU). Thepulsoximeter consists of a peripheral probe combined with the MCU displaying theoxygen saturation and pulse rate on a LCD glass. The same sensor is used for bothheart-rate detection and pulsoximetering in this application. The probe is placed on aperipheral point of the body such as a finger tip, ear lobe or the nose. The probeincludes two light emitting diodes (LEDs), one in the visible red spectrum (660nm) andthe other in the infrared spectrum (940nm). The percentage of oxygen in the body isworked by measuring the intensity from each frequency of light after it transmitsthrough the body and then calculating the ratio between these two intensities.
為提升虛擬儀器傳輸速率與實時性能，擴展監(jiān)測范圍，在VC的軟件平臺上設計了一種全功能虛擬示波器。與傳統(tǒng)虛擬示波器相比，該系統(tǒng)采用嵌入式系統(tǒng)完成信號采集，采用工業(yè)以太網(wǎng)為傳輸介質(zhì)，通過線性插值算法和多線程編程思想，實現(xiàn)波形顯示、參數(shù)計算、頻譜分析以及波形存儲及回放功能。實驗結(jié)果表明，該虛擬示波器可以實現(xiàn)20 kHz采樣頻率下的波形精確顯示，達到預期的各項指標。
Abstract:
o enhance the transfer rate and real-time of virtual instrument performance， expand scope of monitoring， this paper uses the VCs software platform to design a fully functional virtual oscilloscope. Compared with traditional virtual oscilloscope， this system adopts the embedded system to complete the data acquisition， industrial Ethernet as the transmission medium used by the linear interpolation algorithm and multi-threaded programming ideas， namely to achieve waveform display， parameter calculation， spectrum analysis and waveform storage and playback. Experimental results show that the virtual oscilloscope can accurately display the waveform with 20kHz sampling frequency， and achieve the desired targets.
THIS M-FILE USES THE TRANFER MATRIX METHOD TO EVALUATE THE COUPLED-MODE
％EQUATIONS. THE REFLECTION SPECTRUM OF THE GRATING AND THE TRANSMISSION
％SPECTRUM, DELAY AND DISPERSION OF THE FABRY-PEROT FILTER ARE SIMULATED
The Engineering Vibration Toolbox is a set of educational programs
written in Octave by Joseph C. Slater. Also included are a number of help files,
demonstration examples, and data files containing raw experimental data. The
codes include single degree of freedom response, response spectrum, finite
elements, numerical integration, and phase plane analysis.
％WAVETEST Example Matlab script for WAVELET, using NINO3 SST dataset
％
％ See "http://paos.colorado.edu/research/wavelets/"
％ Written January 1998 by C. Torrence
％
％ Modified Oct 1999, changed Global Wavelet Spectrum (GWS) to be sideways,
％ changed all "log" to "log2", changed logarithmic axis on GWS to
％ a normal axis.
