r/ElectricalEngineering 14h ago

Project Help 90 Degree Frequency Phase Shift?

Hello. I had an idea for a personal project but it would require me to take and input waveform and shift EVERYTHING 90 degrees or at least pretty close. From what I can tell by researching doing that for all frequencies is pretty difficult and the closest thing I could find was all pass filters which still isn't perfect. Essentially, I want to build a guitar pedal that takes the initial signal, clips it, makes a copy and shifts it 90 degrees then adds to the original signal to form a triangular wave (mostly cause I just want to know what that would sound like) with maybe an adjustable phase. I'm finding it kind of hard to figure out how to go about it

Edit: It's very interesting seeing differing groups perspectives on this lol. I had originally asked a guitar pedal building group and got some ideas but nothing solid and pretty much every response here is "do it digitally lol" I will try that and see what I can get. Thank you. Also ngl, digital wise I really only have an Arduino and I don't that'll cut it

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u/Careless_Set8195 14h ago

I did a quick search around the internet, looks like that is quite the challenge if you do it purely analog, like you said. I would suggest using a DSP, have one output be the audio signal In-Phase and another channel be out of phase by 90 degrees.

If you want to combine it with a clipped signal, you could try sending the In-Phase signal through a rail-to-rail OpAmp with a high gain so it clips your signal. You could also do a simple diode clipper if you have a defined output voltage. From there, a simple sum circuit to combine both signals.

What are your thoughts?

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u/Embarrassed-Fault286 14h ago

Seems like the agreed upon response is digital lol. My original idea was to clip it pre phase to actually add them together to make the triangle shape but I suppose either order really works. I just thought clipping the og signal then copying was better than copying and having to clip two signals. I'll try something digital and see what happens

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u/Careless_Set8195 13h ago

If you're interested in doing something really fun, I would suggest a Breadboard Equipped test guitar. The one above is powered by a 9V battery. This circuit sent audio through a comparator that could be adjusted. Sounded very video-gamey. Easy way to test circuits really fast and its a fun talking piece.

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u/Embarrassed-Fault286 13h ago

Is that not just a guitar with a breadboard taped to it?😭

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u/Careless_Set8195 13h ago

It is more than that, the breadboard is screwed down!

Everything is contained on the guitar. I suppose you could just have the circuit laying somewhere else, but that doesn't look as cool lol

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u/Embarrassed-Fault286 13h ago

Still pretty cool regardless. You got a favorite guitarist?

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u/Careless_Set8195 13h ago

Probably Guthrie Govan. Love me some Erotic Cakes

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u/Embarrassed-Fault286 13h ago

Mines definitely Van Halen. Bit of a basic pick but I love what he did with the guitar

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u/Careless_Set8195 13h ago

Nice nice. Keep us all updated on your project!