Based on DFT algorithm in the syn-chronous fixed sampling condition,the phase of the capacitor voltage is gained and the tracing of the system resonant fre-quency is realized.

• 采用基于定点同步采样的离散傅里叶变换(DiscreteFourierTransform,简称DFT)得到了电容电压的相位,利用软件锁相环(SoftwarePhaselockedLoop,简称SPLL)实现了试验系统谐振频率的自动跟踪。