The Design And Implement Of Digital Signal Function Generator

The Direct Digital Frequency Synthesis (DDFS) is a kind of new frequency synthesis method and also a revolution in the frequency synthesis techniques. With the development of digital integrated circuits and microelectronic techniques, DDS exhibits its advantages day by day.This paper introduces a high resolution and high stability signal generator design based on CPLD, MCU control technology and direct digital synthesis (DDS). This paper describes several aspects of signal generators based on AD9834 DDS chip. Firstly, the paper introduces many kinds of signal generators that usually used, and then makes some comparison. And the paper describes the project of the signal generator based on AD9834 DDS chip in detail. It contains: basic theory, architecture, function module diagram, hardware schematic diagram and the solution of problems which occurred in system debug is also offered. Method of CPLD' s communication with MCU is utilized in the design to generate high accuracy and wide frequency range signal.In the overall system design, the DDS signal generators would be classified into 6 units: keyboard unit, single chip unit, CPLD unit, DDS unit, analog signal modulator unit, and power unit, where both software and hardware design are accomplished according to each unit.In the design of system hardware, specific analysis and design for how to realize the electric circuits had been carried out.In the design of system software, their main functions were introduced according to units.Finally, on the basis of the main functions of this signal generator, the system functions had been tested, and basing on the specific testing waveform and testing data the result had been analyzed.Both the experiment and experimental result indicated that the designed system is a simple-structured, user-friendly, multi-compatible, very stable and reliable design presenting a great value for practical applications.