Looking for tips on implementing phase distortion

So I have been learning about different types of synthesis and watched a video about how phase distortion works, and it seems like a quite powerful waveshaping method. Essentially the goal is to have a base waveform, and read through parts of it at different speeds. For instance reading through the first half of a cosine wave quite fast, and then the rest slower, to produce a saw like wave.

In the video he represents this with a graph that would be somewhat familiar to us using the sample scanner. A straight line from the bottom left to the top right represents playing back the sample unaltered, like inputing a sawtooth wave into a samplescanner. The playback speed of different segments of the wave are controlled by placing a point on the graph and drawing a new wave that goes from -1 to 1 but goes through the point you placed. The key to the filter like sounds of phase distortion was moving that point (or multiple) around, so you could morph between a saw like wave and a sine wave.

Ideally I could have a unit that takes an input sample, like the sample scanner, and has controls to move the x and y position of a single point to shape the sample. Any good ideas on how to make an oscillator that always starts at -1, goes through a point, and ends at 1?

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I believe this is just phase modulation. All of the oscillator units allow phase modulation. You will want to set f0 to 0Hz and then experiment with different modulations for the phase input.

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I guess my question is how to make a specific modulating oscillator. One which is formed by two lines. One goes from -1 to a node, and one that goes from that node to 1 in such a time that the overall wave created by these two lines would have a constant frequency. The node would have positional control on the x axis, which would be a ratio of the oscillating frequency, and on the y axis from -1 to 1.

Or generally a way to play the first section of a sample at one rate, and the rest of the sample at another rate such that the sample always loops at a constant rate. And so that you have control over the position where the rate change happens.

Hope that makes sense.

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one possible way:
-use whatever app to design custom waveforms which have the characteristics you want (half linear half accelerating etc…)
-load it (or them) into a single cycle oscillator
-use the single cycle oscillator to phase modulate a sine

To make that particular modulation, play around with the feedback control on the sine oscillator and see if you like it. It is essentially a smooth version of what you described.

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Have to try this asap, not sure why I didn’t go there before🤔

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its super cool even with just a sine oscillator , but with the single cycle its just WOW! super customizable waveshaper with scanning options!!! fire