为了设计高分辨率、频率切换相位连续、频率覆盖系数达到106的超低频函数信号发生器,提出了直接数字频率合成DDFS技术,可以合成频率可控的任意波形;以SOPC实现系统设计,利用FPGA实现数字逻辑功能,在LPM_ROM中放入波形数据表,用NIOSII嵌入式软核微处理器实现波形选择、数据处理,输出正弦波、方波、三角波、锯齿波并显示其频率、幅度和相位;测试表明,系统稳定,具有输出波形任意化、低频范围宽和频率精度高的特点.%In order to design Ultra - Low- frequency Signal Generator. There are advantages of high resolution, phase continuous upon frequency switching and coefficient of frequency coverage to 106. The strategy for designing signal generator based on DDFS is proposed. Arbitrary waveform can be synthesised and its frequency can be controlled. System design is achieved based on SOPC. It achieves digital logic functions using FPGA. Waveform data table is put into LPM _ ROM. It achieves waveform selection. Data processing using NIOSII embedded soft-core microprocessor. It outputs sine wave, square wave, triangle wave, sawtooth wave and displays frequency, amplitude and phase. Testing show, its advantages is stable system, arbitrary waveform wide low-frequency range, and high frequency accuracy.
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