Abstract
1990's , the international have mounted the electron and the more advanced country of computer art , have been probing new electronic circuit design procedures actively , have carried out thorough transforming , have got the enormous success and in the field of design procedures , implement etc.The technology designs a field in the electron, programming logic component (if CPLD , the FPGA) application, already get broad popularizing , these components have brought extremely large flexibility to extremely large flexibility. These components can pass the software programming but the design carrying out the heavy structure , thereby feasible hardware's on whose hardware structure and mechanics can go to the lavatory like that like software design rapid. All these has changed the tradition digital system design procedures , has designed process and has designed concept tremendously, have boosted EDA technology promptness developing.
EDA is the abbreviation of electron design automation (Electronic Design Automation) , concept complying with computer-aid design (CAD) , computer-aid manufacturing (CAM) , computer-aid testing (CAT) and computer-aid project (CAE) in the beginning of 1990's develops but comes. The EDA technology is to take computer as implement , the designer goes ahead in EDA software platform , uses hardware describe that language HDL to be completed designing a document , accomplishes logic compiling voluntarily from the computer , melts letter , division , synthesis , optimization , layout , arrangement of wire and simulates and then, Until marrying to specially appointed target chip matches compiling , logic, mapping and programming time be loaded with etc. works. EDA technology turn up , extremely large have improved the wiring design efficiency and may * nature , the labour intensity having lightened a designer.
Circuit designing that QUARTUS| | developing platform in EDA makes use of VHDL language design numerical control frequency division implement on 6.0 originally time, the principle making use of numerical control frequency division designs that music hardware performs a circuit , LPM-ROM being custom-made stores and the music data , take that "Liang Zhu " and "moon represent my two heart " music as example , the music data memory has been reached right away to LPM-ROM, to realize music's coming pure hardware means perform effect. As long as revising music data stored by LPM-ROM, with the person if it were the music music data, makes LPM-ROM customarily other again again , link up to performance being able to realize other music right away in procedure.
Keywords: FPGA/CPLD , music hardware perform circuit , VHDL language design , QUARTUS| | 6.0
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电子琴既可以演奏不同的曲调，又可以发出强弱不同的声音，还可以模仿二胡、笛子、钢琴、黑管以及锣鼓等不同乐器的声音。那么，电子琴的发音原理是怎样的？
大家知道，当物体振动时，能够发出声音。振动的频率不同，声音的音调就不同。在电子琴里，虽然没有振动的弦、簧、管等物体，却有许多特殊的电装置，每个电装置一工作，就会使喇叭发出一定频率的声音。当按动某个琴键时，就会使与它对应的电装置工作，从而使喇叭发出某种音调的声音。
电子琴的音量控制器，实质上是一个可调电阻器。当转动音量控制器旋扭时，可调电阻器的电阻就随着变化。电阻大小的变化，又会引起喇叭声音强弱的变化。所以转动音量控制旋扭时，电子琴发声的响度就随之变化。
当乐器发声时，除了发出某一频率的声音──基音以外，还会发出响度较小、频率加倍的辅助音──谐音。我们听到的乐器的声音是它发出的基音和谐音混合而成的。不同的乐器发出同一基音时，不仅谐音的数目不同，而且各谐音的响度也不同。因而使不同的乐器具有不同的音品。在电子琴里，除了有与基音对应的电装置外，还有与许多谐音对应的电装置，适当地选择不同的谐音电装置，就可以模仿出不同乐器的声音来。
