alt.sci.physics.acoustics

"Richard Crowley" wrote in message
news:13hk17fagdclv42@corp.supernews.com...
> "Chronic Philharmonic" wrote ...
>> "Green Xenon [Radium]" wrote ...
>>> Benj wrote :
>>> > Radium wrote:
>>> > > Could a similar process be done in acoustics? IOW, something like
>>> > > using four 1 KHz sine-wave tones to produce 4 KHz sine-wave tone? If
>>> > > so, how would this be done?
>>>
>>> > Yes, it can but you have to send them through the appropriate non-
>>> > linear devices!
>>>
>>> Just what are these "appropriate non-linear devices"?
>>
>> Something with strong fourth harmonic distortion.
>
> That will take a *single* 1KHz waveform and produce 4KHz.
>
> However, "adding" the frequency of multiple waveforms is a
> different function. I'm not sure such a device actually exists.

Yes, I know. Summing the waveforms in the usual, linear sense, if they are
all the same frequency, 1KHz, will only result in a new 1KHz waveform whose
amplitude depends on the amplitude and relative phase of the inputs.

The only way I know of to get new frequencies is to use some non-linear
device (e.g., modulator). I gave one example, and you only need one waveform
to do it.