ABSTRACT

Direct digital frequency synthesize(DDFS) is a recently and rapidly developed technology which features high frequency resolution．This paper briefly introduces the basic principle of DDS. The basic principle and performance of CPLD chip．Then it mainly describes how to use CPLD chip to design a function generator of high accuracy．The principle of three-phase multi-signal generator based on CPLD and DDS technology is introduced．Based on these，the modules of CPLD design are given．

The multi-wave signal generator is designed based on program-mable logical component CPLD．The VHDL programming realization and the MAX+ plus II development platform. Besides the crystal oscillator and the A/D transformation，the entire system completely integrates on the CPLD chip．The multi-wave signal generator may output the sine-wave，the triangle-wave，the square-wave．Then downloaded under the situation which the entire system hardware connects do not change，and finally output the special profile which user needs．The multi-wave signal generator generates wave which the conventional function signal generators can’t make．Moreover because of the programmable reset feature of the CPLD，the generator can change the wave data conveniently and practice easily．The whole design realizes by the VHDL programmer．Its design process has simple feature，easy modification and high transportation．

Keywords：Signal Generator Design；Three-phase；VHDL；CPLD；MAX+ plus II