示波器fft后频域的幅度与原时域信号幅度的对应关系

示波器fft后频域的幅度与原时域信号幅度
的对应关系
The amplitude of the frequency domain after FFT in an oscilloscope corresponds to the amplitude of the original time-domain signal.
When performing a Fast Fourier Transform (FFT) on a time-domain signal using an oscilloscope, it converts the signal from the time domain to the frequency domain. The frequency domain representation shows the different frequencies present in the original signal and their respective amplitudes.
In the frequency domain, each point represents a specific frequency component. The magnitude of each point indicates how much of that particular frequency component is present in the original signal. In other words, it represents the amplitude of that frequency component.
The relationship between the original time-domain signal's amplitude and its corresponding amplitude in the frequency
domain can be understood through basic principles of
Fourier analysis. According to Fourier theory, any periodic waveform can be represented as a sum of sine and cosine waves with different frequencies and amplitudes.
When we perform FFT on a time-domain waveform, it decomposes this waveform into its constituent sine and cosine waves, each representing a different frequency component. The magnitude spectrum obtained from FFT
reflects these individual components' amplitudes.
Therefore, when you observe the amplitude values in the frequency domain after conducting an FFT on an oscilloscope, they correspond to the amplitudes of specific frequency components present in the original time-domain signal.
To summarize, by performing FFT on a time-domain waveform, an oscilloscope reveals various frequency components and their corresponding magnitudes (amplitude) in the resulting frequency spectrum—the larger magnitude indicates higher contribution or presence of that particular sinusoidal component.
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示波器进行FFT后，频域的幅度与原时域信号的幅度有对应关系。

在示波器上对时域信号进行快速傅里叶变换（FFT）时，它将该信号从时域转换为频域。

频域表示显示了原始信号中存在的不同频率和它们的幅度。

在频域中，每个点代表一个特定的频率分量。

每个点的大小表示该特定频率分量在原始信号中的存在程度，也就是代表该频率分量的幅度。

原时域信号的幅度与其在频域中对应幅度之间的关系可以通过傅里叶分析的基本原理来理解。

根据傅里叶理论，任何周期性波形都可以表示为具有不同频率和振幅的正弦和余弦波之和。

当我们对时域波形进行FFT时，它会将该波形分解为其组成部分——各个正弦和余弦波——它们代表着不同的频率成分。

从FFT获得的幅度谱反映了这些单独成分的振幅。

因此，在示波器上进行FFT后观察到的频域幅度值与原始时域信号中出现的具体频率成分的振幅相对应。

总结一下，通过对时域波形进行FFT变换，示波器揭示了各种不同频率成分及其在生成频谱上所呈现出来（大小决定了某一正弦波成分的出现程度）的幅度。