SDP Search and Record generator
OVERVIEW:
Recognizing the difficulty in creating an SDP service description and search
from scratch, Microsoft is providing a sample utility in bthnscreate.cxx to
automatically create a service or record. This utility can be run to create
an SDP record or to setup an SDP Service, Attribute, or ServiceAttribute
search based on information stored in a human readable file.
針對傳統(tǒng)集成電路（ASIC）功能固定、升級困難等缺點，利用FPGA實現(xiàn)了擴頻通信芯片STEL-2000A的核心功能。使用ISE提供的DDS IP核實現(xiàn)NCO模塊，在下變頻模塊調用了硬核乘法器并引入CIC濾波器進行低通濾波，給出了DQPSK解調的原理和實現(xiàn)方法，推導出一種簡便的引入?仔/4固定相移的實現(xiàn)方法。采用模塊化的設計方法使用VHDL語言編寫出源程序，在Virtex-II Pro 開發(fā)板上成功實現(xiàn)了整個系統(tǒng)。測試結果表明該系統(tǒng)正確實現(xiàn)了STEL-2000A的核心功能。
Abstract:
To overcome drawbacks of ASIC such as fixed functionality and upgrade difficulty, FPGA was used to realize the core functions of STEL-2000A. This paper used the DDS IP core provided by ISE to realize the NCO module, called hard core multiplier and implemented CIC filter in the down converter, described the principle and implementation detail of the demodulation of DQPSK, and derived a simple method to introduce a fixed phase shift of ?仔/4. The VHDL source code was designed by modularity method , and the complete system was successfully implemented on Virtex-II Pro development board. Test results indicate that this system successfully realize the core function of the STEL-2000A.
通過比較各種隔離數(shù)字通信的特點和應用范圍，指出塑料光纖在隔離數(shù)字通信中的優(yōu)勢。使用已經標準化的TOSLINK接口，有利于節(jié)省硬件開發(fā)成本和簡化設計難度。給出了塑料光纖的硬件驅動電路，說明設計過程中的注意事項，對光收發(fā)模塊的電壓特性和頻率特性進行全面試驗，并給出SPI口使用塑料光纖隔離通信的典型應用電路圖。試驗結果表明，該設計可為電力現(xiàn)場、電力電子及儀器儀表的設計提供參考。
Abstract:
y comparing characteristics and applications area of various isolated digital communications， this article indicates advantages of plastic optical fiber in isolated digital communications. Using the standardized TOSLINK interface， it helps to control costs and difficulty in hardware development and design. Then it gives the hardware driver circuit of plastic optical fiber module， explains the noticed details in design process， gives results on the basis of the optical transceiver module voltage characteristics and frequency characteristics tests. Finally，it gives typical application circuit of the SPI communication port by using plastic optical fiber isolation .The results show that this design can be referenced for the power field， power electronics and instrumentation design.
同步技術是跳頻通信系統(tǒng)的關鍵技術之一，尤其是在快速跳頻通信系統(tǒng)中，常規(guī)跳頻通信通過同步字頭攜帶相關碼的方法來實現(xiàn)同步，但對于快跳頻來說，由于是一跳或者多跳傳輸一個調制符號，難以攜帶相關碼。對此引入雙跳頻圖案方法，提出了一種適用于快速跳頻通信系統(tǒng)的同步方案。采用短碼攜帶同步信息，克服了快速跳頻難以攜帶相關碼的困難。分析了同步性能，仿真結果表明該方案同步時間短、虛警概率低、捕獲概率高，同步性能可靠。
Abstract:
Synchronization is one of the key techniques to frequency-hopping communication system， especially in the fast frequency hopping communication system. In conventional frequency hopping communication systems， synchronization can be achieved by synchronization-head which can be used to carry the synchronization information， but for the fast frequency hopping， Because modulation symbol is transmitted by per hop or multi-hop， it is difficult to carry the correlation code. For the limitation of fast frequency hopping in carrying correlation code， a fast frequency-hopping synchronization scheme with two hopping patterns is proposed. The synchronization information is carried by short code， which overcomes the difficulty of correlation code transmission in fast frequency-hopping. The performance of the scheme is analyzed， and simulation results show that the scheme has the advantages of shorter synchronization time， lower probability of false alarm， higher probability of capture and more reliable of synchronization.
針對傳統(tǒng)集成電路（ASIC）功能固定、升級困難等缺點，利用FPGA實現(xiàn)了擴頻通信芯片STEL-2000A的核心功能。使用ISE提供的DDS IP核實現(xiàn)NCO模塊，在下變頻模塊調用了硬核乘法器并引入CIC濾波器進行低通濾波，給出了DQPSK解調的原理和實現(xiàn)方法，推導出一種簡便的引入?仔/4固定相移的實現(xiàn)方法。采用模塊化的設計方法使用VHDL語言編寫出源程序，在Virtex-II Pro 開發(fā)板上成功實現(xiàn)了整個系統(tǒng)。測試結果表明該系統(tǒng)正確實現(xiàn)了STEL-2000A的核心功能。
Abstract:
To overcome drawbacks of ASIC such as fixed functionality and upgrade difficulty, FPGA was used to realize the core functions of STEL-2000A. This paper used the DDS IP core provided by ISE to realize the NCO module, called hard core multiplier and implemented CIC filter in the down converter, described the principle and implementation detail of the demodulation of DQPSK, and derived a simple method to introduce a fixed phase shift of ?仔/4. The VHDL source code was designed by modularity method , and the complete system was successfully implemented on Virtex-II Pro development board. Test results indicate that this system successfully realize the core function of the STEL-2000A.
he AVRcam source files were built using the WinAVR distribution
(version 3.3.1 of GCC). I haven t tested other versions of GCC,
but they should compile without too much difficulty. The makefile
used to build the source is included
This approach addresses two difficulties simultaneously: 1)
the range limitation of mobile robot sensors and 2) the difficulty of detecting buildings in
monocular aerial images. With the suggested method building outlines can be detected
faster than the mobile robot can explore the area by itself, giving the robot an ability to
“see” around corners. At the same time, the approach can compensate for the absence
of elevation data in segmentation of aerial images. Our experiments demonstrate that
ground-level semantic information (wall estimates) allows to focus the segmentation of
the aerial image to find buildings and produce a ground-level semantic map that covers
a larger area than can be built using the onboard sensors.
The AVRcam source files were built using the WinAVR distribution
(version 3.3.1 of GCC). I haven t tested other versions of GCC,
but they should compile without too much difficulty.
* The source files for the AVRcam had the author name and copyright
information added back into them after the judging of the project,
since it states in the competition rules that the author s name
can not be present during their inspection.
* The included source files are the ones that were submitted for
the entry into the Circuit Cellar contest. I have continued to
develop the AVRcam, and have added several new features (such as
ignoring objects that aren t larger than a minimum size, removing
tracked objects that overlap with each, and some general
optimizations). If you are interested in the latest source,
email me at john@jrobot.net
* For more info about the AVRcam, check out http://www.jrobot.net
John Orlando
August 20, 2004
Regardless of the branch of science or engineering, theoreticians have always
been enamored with the notion of expressing their results in the form of
closed-form expressions. Quite often, the elegance of the closed-form solution
is overshadowed by the complexity of its form and the difficulty in evaluating
it numerically. In such instances, one becomes motivated to search instead for
a solution that is simple in form and simple to evaluate.
