Generics and the greatly
expanded collection libraries have tremendously increased the power of
Java 5 and Java 6. But they have also confused many developers who
haven t known how to take advantage of these new features.
Generics and the greatly
expanded collection libraries have tremendously increased the power of
Java 5 and Java 6. But they have also confused many developers who
haven t known how to take advantage of these new features.
As the Hardware Description Language (HDL) enhancement activities have increased over the past year, so too has the complexity in determining which language(s) are the best tools for designers and organizations to continue using or to adopt. Many designers and organizations are contemplating whether they should switch from one HDL to another.
As the Hardware Description Language (HDL) enhancement activities have increased over the past year, so too has the complexity in determining which language(s) are the best tools for designers and organizations to continue using or to adopt. Many designers and organizations are contemplating whether they should switch from one HDL to another.
Abstract: A laser module designer can use a fixed resistor, mechanical pot, digital pot, or a digital-to-analogconverter (DAC) to control the laser driver's modulation and bias currents. The advantages of a programmablemethod (POT or DAC) are that the manufacturing process can be automated and digital control can be applied(e.g., to compensate for temperature). Using POTs can be a more simple approach than a DAC. There can be aslight cost advantage to using a POT, but this is usually not significant relative to other pieces of the design.Using a DAC can offer advantages, including improved linearity (translating to ease of software implementationand ability to hit the required accuracy), increased board density, a wider range of resolutions, a betteroptimization range, ease of use with a negative voltage laser driver, and unit-to-unit consistency
Most circuit designers are familiar with diode dynamiccharacteristics such as charge storage, voltage dependentcapacitance and reverse recovery time. Less commonlyacknowledged and manufacturer specifi ed is diode forwardturn-on time. This parameter describes the timerequired for a diode to turn on and clamp at its forwardvoltage drop. Historically, this extremely short time, unitsof nanoseconds, has been so small that user and vendoralike have essentially ignored it. It is rarely discussed andalmost never specifi ed. Recently, switching regulator clockrate and transition time have become faster, making diodeturn-on time a critical issue. increased clock rates aremandated to achieve smaller magnetics size; decreasedtransition times somewhat aid overall effi ciency but areprincipally needed to minimize IC heat rise. At clock speedsbeyond about 1MHz, transition time losses are the primarysource of die heating.
Highlights the LTC1062 as a lowpass filter in a phase lock loop. Describes how the loop's bandwidth can be increased and the VCO output jitter reduced when the LTC1062 is the loop filter. Compares it with a passive RC loop filter. Also discussed is the use of LTC1062 as simple bandpass and bandstop filter.
提出一種基于凌陽單片機(jī)的步進(jìn)電機(jī)加減速的控制方法。采用凌陽科技推出的16位結(jié)構(gòu)工控單片機(jī)SPMC75F2413A為控制器，由Allegro公司生產(chǎn)的兩相步進(jìn)電機(jī)專用驅(qū)動(dòng)器件SLA7042M構(gòu)成步進(jìn)電機(jī)的驅(qū)動(dòng)電路，在傳統(tǒng)的3段直線加減速控制算法基礎(chǔ)上增加至7段S形曲線加減速過程，控制步進(jìn)電機(jī)的啟動(dòng)和停止。實(shí)驗(yàn)結(jié)果表明，該控制方法克服了直線加減速中不連續(xù)、易造成系統(tǒng)沖擊的問題，整個(gè)系統(tǒng)實(shí)現(xiàn)柔性控制，電機(jī)啟動(dòng)、停止連續(xù)性能提高30%。
Abstract:
The method of controlled stepping motor is referred based on SPMC75F2413A MCU， which adopts the 16 knots SPMC75F2413A MCU as the controller. The special-purpose actuation chip SLA7042M of two stepping motor produced by Allegro Corporation constituted to actuation electric circuit. The purpose of increasing to seven section of S shape curve based on the traditional three sections of straight line is to control the start and stop process of stepping motor. The experimental results show that the control method solves easy to pull-out and overshot problems. The overall system realizes flexible control， and the performance of motor start or stop continuity is increased 30%
在深入了解Flash存儲(chǔ)器的基礎(chǔ)上，采用單片機(jī)自動(dòng)檢測存儲(chǔ)器無效塊。主要通過讀取每一塊的第1、第2頁內(nèi)容，判斷該塊的好壞，并給出具體的實(shí)現(xiàn)過程，以及部分關(guān)鍵的電路原理圖和C語言程序代碼。該設(shè)計(jì)最終實(shí)現(xiàn)單片機(jī)自動(dòng)檢測Flash壞塊的功能，并通過讀取ID號(hào)檢測Flash的性能，同時(shí)該設(shè)計(jì)能夠存儲(chǔ)和讀取1GB數(shù)據(jù)。
Abstract:
On the basis of in-depth understanding the Flash chips，this paper designs a new program which using the SCM to detect the invalid block.Mainly through reading the data of the first and second page to detect the invalid block.Specific implementation procedure was given,and the key circuit schematic diagram and C language program code was introduced.This design achieved the function of using the MCU checks the invalid block finally，and increased the function by reading the ID number of Flash to get the performance of the memory.And the design also can write and read1GB data
