基于CPLD的多用信号发生器的研究与设计

The Study and Design of a CPLD-based All-purpose Signal Generator

以AT89C51系列单片机和CPLD芯片为核心,由运算放大器LM318等器件构成多用信号发生器。该信号发生器利用晶振产生的振荡信号展开设计,运用软件计算出所需波形的频率、相位,再利用RAM读出技术将数据从CPLD的内部读出,并经过高速A/D转换器后输出脉冲信号。该信号经外部滤波放大,产生稳定的方波信号。经过进一步的处理,方波信号转化为三角波和正弦波信号,然后再利用软件部分对该系统的控制,使信号发生器能够产生幅值可调的正弦波、三角波和方波信号,且其输出频率能够在10HZ～100KHZ范围内连续可调。

Centering on the series of AT89C51 single chip computer and the CPLD chip, a type of allpurpose signal generator is made with the LM318 amplifier and other elements. This signal generator utilizes the oscillator signal produced by the crystal to be launched into design. Using the software movement, the frequency and phase of the needed waveform are obtained. Furthermore, using the RAM read-out technology, the signal is readout from the CPLD interior, and at the same time, it is converted into pulse signal by the high speed A/D converter. This pulse signal is magnified when it passes through the exterior filter, and then the stable square-wave signal is produced. Besides, this signal can be changed as the triangular wave and the sine wave signals. Then, by utilizing the software part to control the system, the signals of sine, triangle and square-wave with adjustable-magnitude are obtained, and the output frequency of these signals are also adjustable continuously between 10HZ and 100KHZ.