摘要:本课题是采用低成本的MCS-51系列单片机构成具有高可靠性的函数信号发生器的应用设计。本设计通过单片机运算产生二进制控制信号去控制AD9850进而实现函数波形的产生。基于单片机的函数信号发生器抗干扰性强、功耗低、成本低、易实现，具有很高的实用价值。     本系统以51单片机为控制核心，由电源模块、单片机AT89S52最小系统模块、中断键盘模块、函数信号发生模块、MAX7219显示模块组成。采用中断键盘扫描方式计算所需频率，用数控的方法控制DDS芯片AD9850产生100Hz－40MHz正弦信号，100Hz－5MHz方波信号，波形输出较稳定，且精度较高。采用MAX7219驱动两个四位一体的八段LED数码管，显示出当前波形的频率。系统用C语言编写模块化程序，增强可读性，便于AT89S52对各模块的控制，实现各功能的设置。

关键词：单片机 直接数字频率合成（DDS） AD9850 函数信号 正弦波 方波

Abstract:This issue is low-cost microcontroller MCS-51 family of highly reliable functions constitute a signal generator applications. This design generates a binary control signal MCU operation to control the AD9850 to realize the function of waveform generation. Function Generator based on single chip and strong anti-interference, low power consumption, low cost, easy to implement, has high practical value.      The system control microcontroller core 51 by the power supply module, MCU AT89S52 minimum system module, the keyboard interrupt module, function signal generator module, MAX7219 display module. Calculated by scanning the keyboard interrupt the required frequency, using numerical methods to control DDS chip AD9850 produced 100Hz-40MHz sinusoidal signal, 100Hz-5MHz square wave signal, the waveform output is stable and high precision. Use of MAX7219 drives four in one of eight out of two LED digital tube, showing the frequency of the current waveform. Modular system with C language programs to enhance readability, ease of AT89S52 on the module controlRealize the function of setting.

Key words：Singlechip  Direct Digital Synthesizer(DDS)  AD9850  Function Signal  Sine wave  Square Wave