基于Simulink的数控振荡器性能仿真研究

在FPGA中用查找表技术实现数控振荡器是软件无线电研究的重要内容。累加器步长、累加器控制字等参数决定NCOs的性能，频谱纯度是衡量NCOs的关键指标。借助Simulink仿真平台分析得出相位截断对频谱纯度的影响远大于幅度值的量化。提出相位加抖技术及三种实现提高无杂散动态范围的方法。由仿真分析看出，通过恰当的相位加抖可以极大地提高SFDR。

Simulation and Study of Numerically Controlled Oscillators Performance Based on Simulink

Designing Numerically Controlled Oscillators（NCOs） of Lookup Tables（LUTs） in FPGA is important issues of software radio. Performance of accumulator is decided by step size and word length, spectrum purity is the key design parameter. The phase truncation impacting on the spectrum purity of NCOs is more than amplitude quantization in Simulink Workbench. Phase - dithering is put forward to improve the Spurious Free Dynamic Range（SFDR） of NCOs＇ output. The conclusion is derived from simulation ：phase-dithering is a favoured method of increasing the SFDR performance.