Reference signal
WARNING: This page is about a different car, the 2010 Suzuki Kizashi. However, it is still accessible from the selected car via links, so may be relevant.
The CKP sensor generates 30 pulses of signals each of which has a different waveform length while the crankshaft makes one full rotation, see Inspection of ECM and Its Circuits .
Based on CMP sensor signal and CKP sensor signal, ECM judges which cylinder piston is in the compression stroke.
Also, ECM judge engine speed based on CKP sensor signal.