FFT系数问题 [英] FFT coefficients question

问题描述

我是第一次从事DSP的软件工程师.

I'm a software engineer working on DSP for the first time.

我成功地使用了产生频谱的FFT库.我也了解FFT在输入和输出方面的工作原理，尤其是两个输出数组的内容:

I'm successfully using an FFT library that produces frequency spectrums. I also understand how the FFT works in terms of its inputs and outputs, in particular the contents of the two output arrays:

现在，我的问题是我正在阅读一些新的研究报告，这些报告建议我提取:"FFT系数的能量，方差和总和" .

Now, my problem is that I'm reading some new research reports that suggest that I extract: "the energy, variance, and sum of FFT coefficients".

1. 什么是"FFT系数"?上面显示的实和虚数组的值(根据我的理解)是否与构成余弦和正弦波的振幅相对应?

1. What are the 'FFT coefficients'? Are those the values of the Real and Imaginary arrays shown above, which (from my understanding) correspond to the amplitudes of the constituent cosine and sine waves?

FFT系数的能量"是多少?该术语是来自统计数据还是来自DSP?

What is the 'energy' of the FFT coefficients? Is that terminology from statistics or from DSP?

推荐答案

1. 您是正确的. FFT系数是频域中的信号值.
2. 能量"是系数的平方模.时域或频域中的总能量(所有值的平方模数之和)相同(请参见 Parseval定理).

1. You are correct. FFT coefficients are the signal values in the frequency domain.
2. "Energy" is the square modulus of the coefficients. The total energy (sum of square modulus of all values) in either time or frequency domain is the same (see Parseval's Theorem).

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