基于高阶Σ-Δ调制的任意波形发生器

Arbitrary Signal Generator Based on High Order Σ-Δ Modulation

高信噪比、高精度的校准激励信号源是设备自校准、电子测量及系统辨识等应用中所必须具备的。结合过采样技术,设计并实际研制了一种新型的任意波形发生器。该架构采用高阶Σ-Δ调制技术,能有效降低实现系统工作频段内高信噪比性能所需的转换器位数及过采样率,改善硬件电路设计的复杂度。实际测量结果表明:当任意波形发生器中的调制后信号的数据字长与数模转换器组件的实际使用位数仅为8位时,即可以在有用频带内产生理想14位精度的高准确度的校准或测试信号。

Since stimulus signals with high signal-to-noise ratio and high resolution are necessarily needed in device self-calibration,electronic measurement and system identification applications.This paper designed and developed a novel arbitrary signal generator with the help of over-sampling technique.The architecture adopted high order Σ-Δ modulation method that could efficiently reduce the number of bits used in the converter and the over-sampling-rate required for achieving high signal-to-noise ratio in the system operation bandwidth,which would turn out to release the difficulty in circuits design.Experimental results show that,when both data length of the modulated signal and actual used digits of the DAC component are only 8 bits,the arbitrary signal generator can produce high accuracy calibration or testing signals at the useful frequency band with ideal 14 bits resolution.