You lost me a bit. The laser sensor creates the sawtooth and you are trying discern attributes from it by generating and comparing against a know reference? Remember that you can generate a ramp for the sawtooth by charging or discharging a capacitor from a constant current source then restart with the opposite voltage through a low impedance pulsed switch. Here again the good old 555 timer IC works great for that.

As has been stated there are a great many ways to do the same thing and analog is a great way to keep things simple, circuit wise, but a bear to calibrate. Digital is definitely the way to go. Depending on the actual process rates then either a micro controller for rather slow rates or accelerate it with an FPGA. Obviously we generally interface to an analog world so A/D and D/A converters or PWMs are hard to live without.