afaik triangle is created with odd harmonics. with alternating sign, and with squared attenuation.
Yes, you are correct. I was mistaken. More than once I have heard audiophiles praise old-fashioned tubes, on the premise that their distortion is more listenable because it contains even harmonics, creating triangle waves. (I guess one of these premises is right, the other wrong.)
Solid state components, OTOH, distort by creating square waves, containing harsh-sounding odd harmonics.
Wikipedia refreshed my memory about a triangle wave being created by the combining of odd harmonics.
https://en.wikipedia.org/wiki/Triangle_wave
Nevertheless I found it has this statement, regarding a triangle wave being the integral of a square wave.
btw.
Filtering (in the meaning of lowpass, highpas...) will never add any frequencies. but it can attenuate or amplify the given amplitudes of the existing frequencies.
Yes.
However I continue to juggle two ways of looking at these frequencies: (1) Are they really and truly present in the square wave, or (2) are they a mathematical construct for building the square wave in a theoretical sense?
Looking at post #1, I interpret the square wave as a sudden transition in DC levels... more as a transient, an instigator.
Now, to an experienced eye, the scope trace is telling us there are components attenuating the highs. The net effect is that of a low-pass filter...
However the waveform in post #1 illustrates chiefly a shaping effect, more so than it illustrates a low-pass filter. I imagine the OP discerned this. Hence the question.
From my experience:
I find it hard to analyse the signals frequency components just by a view of a graph. It looks so different when a phase shift is added to the frequency components.
Klaus
Yes, the triangle wave has some of the harmonics phase-inverted. These same harmonics are of the same phase in the square wave.
Therefore what harmonics should we say are present when the waveform is partially a square wave and partially a triangle? Perhaps two same-frequency components cancel, due to one being in phase, the other phase-inverted?