Listen to each of the signals again by clicking on the waveform.

Click on the names below to display a larger version of the spectrograms. Linear Frequency Modulated (LFM) Chirp, Up-Down Chirp , Sine-Wave Modulated Chirp, Birds Chirping .

The time signal for the LFM chirp can also be viewed by plotting LFM Chirp in the Time Domain

Can you point to features in the spectrograms that correspond to the changing tones (or pitch) in the sounds your hear?

Challenge: write the mathematical formula for the sine-wave modulated chirp. Use the concept of instantaneous frequency.

How would you model the bird songs with mathematically generated synthetic chirps?

MATLAB

These were generated with MATLAB. Click here to see the code that computes and displays the spectrograms.


McClellan, Schafer, and Yoder, Signal Processing First, ISBN 0-13-065562-7.
Prentice Hall, Upper Saddle River, NJ 07458. © 2003 Pearson Education, Inc.