Fourier transform of the magnitude of the fourier transformed signal

1. What is the magnitude of a Fourier transform?
2. How do you find the magnitude of a Fourier series?

What is the magnitude of a Fourier transform?

For each frequency, the magnitude (absolute value) of the complex value represents the amplitude of a constituent complex sinusoid with that frequency, and the argument of the complex value represents that complex sinusoid's phase offset. If a frequency is not present, the transform has a value of 0 for that frequency.

How do you find the magnitude of a Fourier series?

Alternatively, the signal y(t) may be described by the magnitudes D_n and the phase angles φ_n: where the magnitude and the phase angle can be calculated from the Fourier coefficients as follows: φ_n = tan^-1 (B_n/A_n). The following interactive example shows you how to combine sines and cosines to form a signal y(t).