利用直接数字频率合成技术设计信号源

Using the direct digital frequency synthesis technology to design the signal source

采用模拟电路设计的信号源存在频率精度不高、调试与维修不方便、工作不够稳定以及直接升级困难等缺点。文章提出了利用直接数字频率合成技术(Direction Digital Frequency Synthesis Technology简称DDS)设计信号源,分别介绍了基于CPLD、单片机、DDS芯片和简单数字电路等4种信号源设计方法。4种方法都包含了信号数据表、读取数据表的电路、D/A电路和低通滤波器电路。更改数据表的数据就可以改变信号类型,用不同速率读取数据表中的数据就可以得到不同的信号频率。这2种值的改变都可以通过软件实现,实现了信号源设计的软件化。改进设计后的信号源不仅有很高的频率精度,而且电路结构简单、电路工作稳定、维修方便。

The signal source that was designed by using the analogue circuit has some disadvantages,such as not enough frequency precision,inconveniency for adjustments and maintenances,unstable performance and difficult to upgrade.To improve the traditional signal source circuit,the paper provides the direction digital frequency synthesis technology(for short:DDS)to design the signal source circuit.It can solve the problem in existence as well as realize the source circuit design by software.