一种程控宽频带多波形信号发生器的研制

针对目前专门的函数信号发生器IC功能简单、精度不高、调节方式不灵活等缺点和DDS芯片外围电路设计复杂、成本较高等问题,设计研制了一种程控宽频带多波形信号发生器。该信号发生器采用单片机STC89C52控制专用函数发生器MAX038实现,通过键盘设置输出波形类型、频率、占空比和幅度等各种参数,采用闭环控制方法对输出频率自动反馈控制以提高频率精度,并由八位LED显示器实时显示状态信息。实际运行结果表明:该系统可以产生频率范围在1Hz~20MHz、幅度在2~10V(VPP)连续可调、占空比在10%~90%变化的三角波、锯齿波、方波、正弦波和PWM波,输出频率精度小于0.01%。该仪器具有电路结构简单、性能优良、成本低廉、功能多样、使用方便等优点,在生产实践和科技研究领域中具有广泛的应用前景。

Development of a Program-Controlled and Wide-Frequency Multi-Waveform Signal Generator

The present special function signal generator integrated circuits （IC） have disadvantages of simple function, low accuracy, inflexible adjustment operation, and so on. Meanwhile the direct digital synthesizers （DDS） have im- perfections such as complex design of peripheral circuit, high cost and so forth. For this reason, a program-controlled and wide-frequency multi-waveform signal generator is designed and developed in this paper. It is implemented by employing a STC89C52 single-chip microcomputer to control the specific function generator MAX038. The various parameters of generated signals, such as the waveform type, the frequency, the duty cycle and the amplitude, are set by using the keyboard. In order to improve the frequency precision of produced signals, a closed loop control method is adopted to automatically feed back and control the output frequency. In addition, the status information is shown in the 8-bit LED display in real time. The actual running results show that this system can produce triangle, saw- tooth, square, sine and PWM waveforms, which frequency can range from 1Hz to 20MHz and amplitude can be con- tinuously adjusted between 2V and 10V（Vee） and duty cycle can vary from 10 to 90 percent; moreover the output frequency accuracy value is less than 0.01%. This instrument has many advantages such as simple circuit structure, excellent performance, low cost, diverse function, easy to operate, etc. Therefore it has a broad application prospect in the fields of productive practice and science and technology research.