Page 29 - Vibrations

This is sweep up and sweep down as shown on the

previous page.

When representing information in the frequency

domain there are two types of spectrum

The Magnitude Spectrum, defined as,

2
2
|()| = √[()] + [()]

When you perform the Fourier Transform, the

spectrum H( f ) is complex - with real and imaginary

parts.

The Phase Spectrum, defined as,

[()]

() = tan −1 [ ]
[()]

The value of, -π/2 < φ( f ) <π/2

You have already been looking at the magnitude

spectrum when investigating the harmonics of a

square wave.

The phase spectrum comes in useful when looking

at audio applications where phase information is

important for stereo and surround sound.

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