[sdiy] Harmonics Question

[Veronica Merryfield]

Kyle et al

This is a definition thing. "A harmonic of a wave is a component frequency of the signal that is an integer multiple of the fundamental frequency, i.e. if the fundamental frequency is f, the harmonics have frequencies 2f, 3f, 4f, . . . etc" - wikipeadia, other definitions follow a very similar vein. 

String and columns of air, at a cursory glance, seem to follow this definition, but one closer inspection there are other physical effects occurring which tend to produce sharpening effects, but the wave is still an integer multiple (string length is changing for instance).

Transistors tend to square signals and tubes tend to triangle the signals. Over driven transistors tend to hit the rails hard where as tubes tend to limit dv/dt. I recently got my self a copy of Electronic Devices and Circuits by Millman and Halkias, 1967 for the express reason of the covering of the physics of devices including tubes pre digital world - I highly recommend it. 


On 2011-11-02, at 8:51 PM, Kyle Stephens wrote:

> This has always been rather unclear to me: are harmonics measured in integers because that's an "easy" metric to employ, or do they occur naturally in integer multiples? Did the phenomenon or its measurement come first?
> 
> For some reason that seems overly "convenient" to me, or is it just a lucky happenstance? Though obviously other things in nature occur in whole numbers (at least I think I have "2" arms).
> 
> Follow up question: just how do vacuum tubes tend to produce predominantly even harmonics, and likewise why do transistors rock the odd harmonics?
> 
> 
> _Kyle
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