Introduction to Audio Spectrum Analysis

Spectrum analysis of real-world signals typically occurs over short time segments. We are therefore most interested in short-time spectrum analysis:

• Spectral content typically varies over time.
• The human ear uses less than one second of past sound to form a spectrum.
• There is a limit to the length of signal we can analyze at once.

To extract and analyze a sound segment, it is necessary to apply a window function. An unmodified segment extraction corresponds to a ``rectangular window''.

Everything we `look at' will be through a `window', hence it is important to realize what the window is doing to our underlying signal.

Applications we'll discuss first:

• Spectral Analysis for Display
• FIR Filter Design by Window Method