任意函数发生器的相位截断对数字合成信号影响的分析

在任意函数发生器中，相位累加器的相位截断效应使合成信号中含有寄生噪声，降低了合成信号的信噪比，本文利用非均匀取样模型的数字频谱分析方法研究了相位截断对数字合成任意信号的影响。给出了合成信号的数字频谱及信噪比的一般表达式。并讨论了存在相位截断时的相位累加器位数，波形存储器容量及频率控制字与合成信号序列输出信噪比之间的关系。

Analysis of the Effects on Digitally Synthesized Signals of Arbitary Function Generator due to Phase-accumulator Truncation

This paper presents an analysis of output spectra of arbitrary function generator in the presence of phase-accumulator truncation. With digital spectrum analysis technology, a closed form expression is derived which relates the magnitude, number and position of the spu-rious noise lines in the output spectra to the waveform memory size, the amount of phase accu-mulator truncation and frequency control word. Furthermore, we derive the signaLto-noise ra-tio of digitally synthesized signals due to the truncation. This investigation is helpful to the de-sign and the analysis of arbitrary function generator and digital frequency synthesizer.