针对传统手工校准频谱分析仪存在校准时间久、效率低、容易引入人为误差等问题。
For the problem of the traditional manual calibration spectrum analyzer calibration need long time, low efficiency, easy to introduce human error.
联合时频分布方法把整体频谱推广到局部频率，根据频率随着时间的变化情况，对信号进行有效的分析。
Generalized into local frequency from integral frequency, the method of joint time-frequency distribution effectively analyzes the signal based on the variation of frequency with time.
该方法通过频谱分析，可以计算出全局性的主要周期，从而反映出水文时间序列的整体特性。
By spectral analyzing, the overall period can be calculated, thus the holistic characteristics of hydrological time series can be reflected.
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