This paper proposes a method by translating the series from time domain to frequency domain, then to a string sequence.

采用变换法则对时间序列进行从时域到频域的转换，再将转换后的数据按照一定的规则变换成字符序列；

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In fact, the FFT spectrum is the convolution between read time series and window function in domain of frequency, the dominant frequency position influence on leakage should not be ignored.

由于实际信号和窗函数在频域为卷积关系，所以应该考虑实际频率在FFT谱上所处的位置。

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This paper describes the need to transform the continuous periodic signal in time domain to the discrete signal in frequency domain by using Fourier Series (FS).

讨论了利用傅里叶级数把连续周期时域信号转换成离散的频域信号的必要性。

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