Wave forms

So to understand this video correctly;

1) ECU inputs are in the form of alternating sin/cos waves (or any other alternating waveform like the one at 1:30) and outputs are PWM signals (always square waves) ?

2) Different sensors feedback different kind of AC wave forms back to the ECU (one kind of waveform is the one at 1:30)?

3) Can cycle times be increased/decreased?

4) Is there any way waveforms can be analyzed other than using an oscilloscope? for example, via the tuning software?

1. Inputs to the ECU may be a straight voltage such as what you'd see from a TPS or MAP sensor. The signals from the likes of the crank and cam sensors will be a waveform.

2. Yes, the waveform could be a square wave as you'd expect from a digital sensor (hall or optical), or a sine wave form which you'd expect from a magnetic sensor (very common for rpm sensors).

3. Yes, but this is very dependent on the out put you're controlling and the setup.

4. Some ECUs have a built in scope function for analysing the inputs.

understood. so engine mechanicals that follow a sinusoidal operation (rotating cams and crank from 0-2pi radians) would follow a (AC) wave form?

what about the throttle position sensor or MAP sensor operation causes it to have a straight voltage output signal?

is there any quality that classifies these sensors differently or did manufacturers just choose to have them interact in this way for convenience from an engineering perspective?