Superposition of sinusoids: frequency domain

The superposition of two signals is just a fancy term for adding them. When we add two sinusoids of the same frequency, we get a new sinusoid with that same frequency, but with a different amplitude and phase. When we add two sinusoids with different frequencies, we get a more complicated looking signal.

Example: Superposition of two sinusoids with the same frequency

Example: Superposition of two sinusoids with different frequencies

Frequency domain: Plot of amplitude and phase vs. frequency

Example: Amplitude modulation in the frequency domain

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