Is something like this possible with the er-301?
So you could achieve quite a bit of that with the sample scanner unit. It is essentially a transfer function. You give it a sample and based on the incoming voltage it references a location on the sample. If you input 0v it outputs the value in the middle of the sample. If you give it -5 v it outputs the value at the start of the sample. 5v outputs at the end. If you give it more than 5v it wraps and references the start again. I believe what is happening in that module is that if the input goes over a certain threshold it will wrap back around.
You should be able to achieve this by loading a ramp wave sample into the sample scanner. Try increasing the gain into the sample scanner to get more reflections. Also try mixing an offset voltage with the input signal to get those pwm effects
I think that module is doing some other stuff too but I’m not sure what. In general the sample scanner is a great tool for waveshaping.