download the audio file 4.wav.gz

hints :

• Setup baudline to be a Netscape helper application as described in the FAQ.
• Turn on the 60 Hz notch filter in the play deck.
• Try playing the mystery signal at different speeds, slow it down or drop it an octave.
• Loop on the transitional points, play it again and again until you start to hear things.
• Use baudline's harmonic helper bars and delta measurement bars to determine the harmonic relationships.
• What is the folding frequency?  What direction are the ramps going?   What does it mean?

What is it?

Click here for the answer.