基于线性调频信号的ADC时钟抖动误差分析

模数转换器的时钟抖动引起输出信号的误差,该误差会影响后继的数字信号处理.分析了输入为线性调频信号时,模数转换器中由时钟抖动引起的误差.在给出误差平均功率表达式的基础上,推导出信噪比的近似计算公式.并利用该计算公式,对影响信噪比的各种因素依次进行讨论,其中信号带宽和时钟抖动参数的增大都会降低输出信噪比,而信号时宽和采样频率的变化对信噪比影响非常小.仿真结果验证了信噪比计算公式的正确性.

Analysis of clock shaking error in ADC based on linear frequency modulated signal

The error of output signal is caused by clock shaking in the analog-to-digital converter,which can affect the succeeding signal processing.The error caused by clock shaking in the analog-to-digital converter is analyzed when the input signal is in linear frequency modulated mode.An approximate formula of the signal-to-noise ratio is obtained based on the expression of the average error power.Various factors that affect the signal-to-noise ratio are discussed successively.The signal-to-noise ratio in output signals is reduced with the increase of signal bandwidth and the parameter of clock shaking,and the change of the duration of signal and sampling frequency makes little effect for signal-tonoise ratio.Simulation results demonstrate the correctness of the proposed formula.