針對(duì)目前使用的RS232接口數(shù)字化B超鍵盤存在PC主機(jī)啟動(dòng)時(shí)不能設(shè)置BIOS，提出一種PS2鍵盤的設(shè)計(jì)方法。基于W78E052D單片機(jī)，采用8通道串行A/D轉(zhuǎn)換器設(shè)計(jì)了8個(gè)TGC電位器信息采集電路，電位器位置信息以鍵盤掃描碼序列形式發(fā)送，正交編碼器信號(hào)通過XC9536XL轉(zhuǎn)換為單片機(jī)可接收的中斷信號(hào)，軟件接收到中斷信息后等效處理成按鍵。結(jié)果表明，在滿足開機(jī)可設(shè)置BIOS同時(shí)，又可實(shí)現(xiàn)超聲特有功能，不需要專門設(shè)計(jì)驅(qū)動(dòng)程序，接口簡(jiǎn)單，成本低。
Abstract: Aiming at the problem of the digital ultrasonic diagnostic imaging system keyboard with RS232 interface currently used couldn?蒺t set the BIOS when the PC boot， this paper proposed a design method of PS2 keyboards. Based on W78E052D microcontroller，designed eight TGC potentiometers information acquisition circuit with 8-channel serial A/D converter， potentiometer position information sent out with keyboard scan code sequentially.The control circuit based on XC9536 CPLD is used for converting the mechanical actions of the encoders into the signals that can be identified by the MCU， software received interrupt information and equivalently treatmented as key. The results show that the BIOS can be set to meet the boot， ultrasound specific functionality can be achieved at the same time， it does not require specially designed driver，the interface is simple and low cost.
Bing is a point-to-point bandwidth measurement tool (hence the b ), based on ping. Bing determines the real (raw, as opposed to available or average) throughput on a link by measuring ICMP echo requests roundtrip times for different packet sizes for each end of the link
本書提供用J B u i l d e r開發(fā)數(shù)據(jù)庫(kù)應(yīng)用程序、創(chuàng)建分布式應(yīng)用程序以及編寫J a v a B e a n
組件的高級(jí)資料。它包括下列幾個(gè)部分：
• 第一部分是“開發(fā)數(shù)據(jù)庫(kù)應(yīng)用程序”，它提供關(guān)于使用J b u i l d e r的D a t a E x p r e s s數(shù)據(jù)
庫(kù)體系結(jié)構(gòu)的信息，并解釋原始數(shù)據(jù)組件和類之間的相互關(guān)系，以及怎樣使用它
們來創(chuàng)建你的數(shù)據(jù)庫(kù)應(yīng)用程序。它還解釋怎樣使用Data Modeler(數(shù)據(jù)模型器)和
Application Generator（應(yīng)用程序生成器）創(chuàng)建數(shù)據(jù)驅(qū)動(dòng)的客戶機(jī)/服務(wù)器應(yīng)用程
序。
• 第二部分是“開發(fā)分布式應(yīng)用程序”，它提供關(guān)于使用ORB Explorer、用J B u i l d e r
創(chuàng)建多級(jí)的分布應(yīng)用程序、調(diào)試分布式應(yīng)用程序、用J a v a定義C O R B A接口以及
使用s e r v l e t等的信息。
• 第三部分是“創(chuàng)建J a v a B e a n”，它解釋怎樣開發(fā)新的J a v a B e a n組件，描述在組件
開發(fā)中涉及的任務(wù), 怎樣使用B e a n s E x p r e s s創(chuàng)建新的J a v a B e a n，以及關(guān)于屬性、
事件、B e a nIn f o類和其他方面的詳細(xì)情況。
實(shí)現(xiàn)最優(yōu)二叉樹的構(gòu)造；在此基礎(chǔ)上完成哈夫曼編碼器與譯碼器。 假設(shè)報(bào)文中只會(huì)出現(xiàn)如下表所示的字符：
字符 A B C D E F G H I J K L M N
頻度 186 64 13 22 32 103 21 15 47 57 1 5 32 20 57
字符 O P Q R S T U V W X Y Z ， ．
頻度 63 15 1 48 51 80 23 8 18 1 16 1 6 2
要求完成的系統(tǒng)應(yīng)具備如下的功能：
1．初始化。從終端（文件）讀入字符集的數(shù)據(jù)信息，。建立哈夫曼樹。
2．編碼：利用已建好的哈夫曼樹對(duì)明文文件進(jìn)行編碼，并存入目標(biāo)文件（哈夫曼碼文件）。
3．譯碼：利用已建好的哈夫曼樹對(duì)目標(biāo)文件（哈夫曼碼文件）進(jìn)行編碼，并存入指定的明文文件。
4．輸出哈夫曼編碼文件：輸出每一個(gè)字符的哈夫曼編碼。
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隨著光伏發(fā)電系統(tǒng)快速發(fā)展,以及電動(dòng)汽車充電樁的普及,傳統(tǒng)的剩余電流保護(hù)器無法滿足實(shí)際需求。介紹了一款B型剩余電流保護(hù)器,采用磁調(diào)制剩余電流互感器和零序電流互感器采集剩余電流。根據(jù)GB/T 22794—2017標(biāo)準(zhǔn)要求,可識(shí)別1 kHz及以下的正弦交流、帶和不帶直流分量的脈動(dòng)直流、平滑直流等剩余電流信號(hào)。經(jīng)信號(hào)調(diào)理電路將電壓信號(hào)送到單片機(jī)進(jìn)行采集和判斷。通過試驗(yàn)測(cè)試,該樣機(jī)在測(cè)試精度和速度上均符合國(guó)家標(biāo)準(zhǔn)的相關(guān)要求。The rapid development of photovoltaic power generation systems and the popularity of electric vehicle charging piles make the traditional residual current protective devices unable to meet the actual demand.This paper proposed a type B residual current protective device,which uses the magnetically modulated residual current transformer and the zero sequence current transformer to acquire the residual current.According to the requirements of GB/T 22794—2017,the type B residual current protective device can detect sinusoidal AC residual current of 1kHz and below 1kHz,pulsating DC residual current with and without DC component,smooth DC residual current and so on.The signal processing circuit sends the voltage signal to the MCU for acquisition and judgment.Through experimental tests,the device meets the relevant requirements of national standards in terms of test accuracy and speed.
