相位噪声对误差向量幅度的影响

Effect of Phase Noise on Error Vector Magnitude

对本振源相位噪声与直接变频发射机误差向量(EVM)之间的关系进行了分析,综合考虑了测试电路中升余弦滤波器的影响,在锁相环路(PLL)建模方面引入了峰值相噪以及噪声底的因素。通过Matlab仿真,给出了部分典型情况下本振源相位噪声与EVM之间的对应关系曲线,仿真结果表明峰值噪声和升余弦滤波器的确对直接变频发射机的误差向量有不可忽略的较大影响,从而大大提高了EVM估算的精度。

Error Vector Magnitude （EVM） is a key parameter for the transmitter evaluation. To study the effects of phase noise of local oscillator on Error Vector Magnitude （EVM） of direct frequency converter, a set of equations including the phase noise peaks at the loop bandwidth and the noise bottom is deduced considering the effect of the raised cosine filter in the measurement circuits. Finally, simulation results through Matlab indicate the above considerations do be critical for an accurate calculation.