# Damped wave harmonics

• posted

Can anyone tell me if damped waves (ringing), by their nature, incorporate harmonics of the fundamental frequency?

Bob Stern

• posted

I'm no math genius nor do I claim I'm correct but I'll guess yes..A damped wave "'ping, boing, pong, thump" contains harmonics. In order for amplitude to change..there must be distortion and distortion is composed of harmonics and these harmonics are above and related to the fundamental frequency. I think everything has harmonics with the exception of a pure continuous tone..and no signal..

D from BC

• posted

oops pure continuous sine wave not tone..

1:22am in BC...zzzzzz :P D from BC
• posted

No, not harmonics. But it will contain extra frequencies in a narrow band around the "fundamental". The width of the band is determined by the decay time, i.e. a longer decay time results in a narrower frequency band than a shorter decay time.

Harmonics appear when you are dealing with a periodic signal, which this example isn't.

Regards,

Mark

• posted

That last bit is a little over simplified. A decaying squarewave has the harmonics. There is a band around each that is the sidebands for its decay. When you have a signal that you would describe as a modulated version of some periodic function, the frequency content can be described as having harmonics and side bands around them.

• posted

Well, yeah, but that's because it is a square wave. The harmonics don't come about as a result of the decaying.

I interpreted the OP's question as to whether decaying of a wave will generate harmonics. The answer is no.

Mark

• posted

Yes, that is one way to take his question. Another would be to take it as "do the other frequencies no longer land on multiples of the fundamental". This is more along the line I took it.